basic helix-loop-helix (bHLH) domain found in twist-related protein 1 (TWIST1) and similar proteins; TWIST1, also termed Class A basic helix-loop-helix protein 38 (bHLHa38), or H-twist, is a bHLH transcriptional regulator that inhibits myogenesis by sequestrating E proteins, inhibiting trans-activation by MEF2, and inhibiting DNA-binding by MYOD1 through physical interaction. It also represses expression of proinflammatory cytokines such as TNFA and IL1B. In addition, TWIST1 is involved in cancer development and progression.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 4507741   98 GSPQSYEELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQSDELDSKMAS 174
Cdd:cd11412   1 GSPQSFEELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQSDELDSKMAS 77

basic helix-loop-helix (bHLH) domain found in twist-related protein 1 (TWIST1) and similar proteins; TWIST1, also termed Class A basic helix-loop-helix protein 38 (bHLHa38), or H-twist, is a bHLH transcriptional regulator that inhibits myogenesis by sequestrating E proteins, inhibiting trans-activation by MEF2, and inhibiting DNA-binding by MYOD1 through physical interaction. It also represses expression of proinflammatory cytokines such as TNFA and IL1B. In addition, TWIST1 is involved in cancer development and progression.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 4507741   98 GSPQSYEELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQSDELDSKMAS 174
Cdd:cd11412   1 GSPQSFEELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQSDELDSKMAS 77

helix loop helix domain;

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|...
gi 4507741     114 NVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQS 165
Cdd:smart00353   1 NARERRRRRKINEAFDELRSLLPTLPKNkKLSKAEILRLAIEYIKSLQEELQK 53

basic helix-loop-helix (bHLH) domain found in twist-related protein 1 (TWIST1) and similar proteins; TWIST1, also termed Class A basic helix-loop-helix protein 38 (bHLHa38), or H-twist, is a bHLH transcriptional regulator that inhibits myogenesis by sequestrating E proteins, inhibiting trans-activation by MEF2, and inhibiting DNA-binding by MYOD1 through physical interaction. It also represses expression of proinflammatory cytokines such as TNFA and IL1B. In addition, TWIST1 is involved in cancer development and progression.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 4507741   98 GSPQSYEELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQSDELDSKMAS 174
Cdd:cd11412   1 GSPQSFEELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQSDELDSKMAS 77

basic helix-loop-helix (bHLH) domain found in twist-related protein (TWIST) family; The TWIST family includes TWIST1 and TWIST2, which are highly homologous bHLH transcription factors that promote epithelial-mesenchymal transition (EMT) during development and tumor metastasis. They are involved in the negative regulation of cellular determination and in the differentiation of several lineages, including myogenesis, osteogenesis, and neurogenesis. TWIST factors express in broad partially-overlapping patterns during embryo development and dimerize with a broad sets of dimer partners that form numerous unique transcriptional complexes to regulate embryonic development.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQSDE 167
Cdd:cd11464   1 QRVLANVRERQRTQSLNEAFTSLRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLRSDE 59

basic helix-loop-helix (bHLH) domain found in heart- and neural crest derivatives-expressed protein (HAND) family; The HAND family includes two bHLH transcription factors, HAND1 and HAND2. HAND1, also termed Class A basic helix-loop-helix protein 27 (bHLHa27), or extraembryonic tissues, heart, autonomic nervous system and neural crest derivatives-expressed protein 1 (eHAND), plays an essential role in both trophoblast-giant cells differentiation and in cardiac morphogenesis. HAND2, also termed Class A basic helix-loop-helix protein 26 (bHLHa26), or deciduum, heart, autonomic nervous system and neural crest derivatives-expressed protein 2 (dHAND), is essential for cardiac morphogenesis, particularly for the formation of the right ventricle and of the aortic arch arteries.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 4507741  110 RVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd11466   2 RGSANKKERRRTQSINSAFADLRECIPNVPADtKLSKIKTLRLATSYIAYLMDVL 56

basic helix-loop-helix (bHLH) domain found in Fer3-like protein (FERD3L), pancreas transcription factor 1 subunit alpha (PTF1A) and similar proteins; The family corresponds to a group of bHLH transcription factors, including FERD3L and PTF1A. FERD3L, also termed basic helix-loop-helix protein N-twist, or Class A basic helix-loop-helix protein 31 (bHLHa31), or nephew of atonal 3 (NATO3), or Neuronal twist (NTWIST), is expressed in the developing central nervous system (CNS). It regulates floor plate (FP) cells development. FP is a critical organizing center located at the ventral-most midline of the neural tube. FERD3L binds to the E-box and functions as inhibitor of transcription. PTF1A, also termed Class A basic helix-loop-helix protein 29 (bHLHa29), or pancreas-specific transcription factor 1a, or bHLH transcription factor p48, or p48 DNA-binding subunit of transcription factor PTF1 (PTF1-p48), is implicated in the cell fate determination in various organs. It binds to the E-box consensus sequence 5'-CANNTG-3' and plays a role in early and late pancreas development and differentiation.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSDK-LSKIQTLKLAARYIDFLYQVL 163
Cdd:cd19686   1 QRQAANIRERKRMRSINDAFDGLRRHIPTFPYEKrLSKVDTLRLAIQYINFLTELL 56

basic helix-loop-helix (bHLH) domain found in T-cell acute lymphocytic leukemia protein 2 (TAL-2) and similar proteins; TAL-2, also termed Class A basic helix-loop-helix protein 19 (bHLHa19), is a bHLH transcription factor essential for the normal brain development. It has been implicated in T-cell acute lymphoblastic leukemia.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 4507741  108 TQRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQSDE 167
Cdd:cd19707   1 TRKIFTNTRERWRQQNVNSAFAELRKLIPTHPPDkKLSKNEILRLAMKYINFLVKLLGDQG 61

basic helix-loop-helix (bHLH) domain found in pancreas transcription factor 1 subunit alpha (PTF1A) and similar proteins; PTF1A, also termed Class A basic helix-loop-helix protein 29 (bHLHa29), or pancreas-specific transcription factor 1a, or bHLH transcription factor p48, or p48 DNA-binding subunit of transcription factor PTF1 (PTF1-p48), is a bHLH transcription factor implicated in the cell fate determination in various organs. It binds to the E-box consensus sequence 5'-CANNTG-3' and plays a role in early and late pancreas development and differentiation.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSDK-LSKIQTLKLAARYIDFLYQVL 163
Cdd:cd11417   1 QRQAANLRERRRMQSINDAFEGLRSHIPTLPYEKrLSKVDTLRLAIGYINFLSELV 56

basic helix-loop-helix (bHLH) domain found in T-cell acute lymphocytic leukemia protein/ lymphoblastic leukemia-derived sequence (TAL/LYL) family; The TAL/LYL family includes a group of bHLH transcription factors (TAL1, TAL2 and LYL1) implicated in T cell acute leukaemia. They act as mediators of T cell leukaemogenesis. TAL-1, also termed Class A basic helix-loop-helix protein 17 (bHLHa17), or stem cell protein (SCL), or T-cell leukemia/lymphoma protein 5, is a hematopoietic-specific bHLH transcription factor that functions in embryonic and adult hematopoiesis in vertebrates. It is also required for embryonic vascular remodeling. It acts as a regulator of erythroid differentiation and binds to regulatory regions of a large cohort of erythroid genes as part of a complex with GATA-1, LMO2 and Ldb1. TAL-2, also termed Class A basic helix-loop-helix protein 19 (bHLHa19), is a bHLH transcription factor essential for the normal brain development. Lyl-1, also termed Class A basic helix-loop-helix protein 18 (bHLHa18), or lymphoblastic leukemia-derived sequence 1, is a proto-oncogenic bHLH transcription factor that plays an important role in hematopoietic stem cell function and is required for the late stages of postnatal angiogenesis to limit the formation of new blood vessels, notably by regulating the activity of the small GTPase Rap1. LYL-1 deficiency induces a stress erythropoiesis.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQSDE 167
Cdd:cd11413   1 RRIFTNTRERWRQQNVNGAFAELRKLIPTHPPDkKLSKNEILRLAMKYIKFLEKILEDQE 60

basic helix-loop-helix (bHLH) domain found in factor in the germline alpha (FIGLA) and similar proteins; FIGLA, also termed FIGalpha, or Class C basic helix-loop-helix protein 8 (bHLHc8), or folliculogenesis-specific basic helix-loop-helix protein, or transcription factor FIGa, is a germ-cell-specific bHLH transcription factor expressed abundantly in female and less so in male germ cells. It is essential for primordial follicle formation and expression of many genes required for folliculogenesis, fertilization and early embryonic survival. FIGLA knockout mice cannot form primordial follicles and lose oocytes rapidly after birth, whereas male gonads are unaffected.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4507741  110 RVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd11422   1 RRVANARERERVRNLNSGFSKLRRIVPLIPRDrKPSKVDTLKGATEYIRLLQRILE 56

basic helix-loop-helix (bHLH) domain found in achaete-scute complex-like (ASCL) family; The achaete-scute complex-like (ASCL, also known as achaete-scute complex homolog or ASH) family of bHLH transcription factors, ASCL1-5, have been implicated in cell fate specification and differentiation. They are critical for proper development of the nervous system. The deregulation of ASCL plays a key role in psychiatric and neurological disorders. ASCL-1, also termed Class A basic helix-loop-helix protein 46 (bHLHa46), or achaete-scute homolog 1 (ASH-1), or mammalian achaete-scute homolog 1 (Mash1), is a neural-specific bHLH transcription factor that is expressed in subsets of neural progenitors in both the central and peripheral nervous system. It plays a key role in neuronal differentiation and specification in the nervous system. ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete-scute homolog 2 (Mash2), is a bHLH transcription factor that is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves. ASCL-3, also termed Class A basic helix-loop-helix protein 42 (bHLHa42), or bHLH transcriptional regulator Sgn-1, or achaete-scute homolog 3 (ASH-3), is a bHLH transcription factor specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis. The family also includes Drosophila melanogaster achaete-scute complex (AS-C) proteins, which consists of lethal of scute (also known as achaete-scute complex protein T3 or AST3), scute (also known as achaete-scute complex protein T4 or AST4), achaete (also known as achaete-scute complex protein T5 or AST5), and asense (also known as achaete-scute complex protein T8 or AST8). They are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system, as well as in sex determination and dosage compensation.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 4507741  114 NVRERQRTQSLNEAFAALRKIIPTLPSDK-LSKIQTLKLAARYIDFLYQVL 163
Cdd:cd11418   6 NERERRRVQAVNDAFDRLRQHVPYLKRRKkLSKVKTLRRAIEYIRHLQKLL 56

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster protein taxi and similar proteins; Protein taxi, also termed protein delilah (Dei), is a bHLH transcription factor that is involved in regulation of cell adhesion and attachment that is expressed in specialized cells that provide anchoring sites to either muscles (tendon cells), or proprioceptors (chordotonal attachment cells) during embryonic development. It probably plays an important role in the differentiation of epidermal cells into the tendon cells that form the attachment sites for all muscles.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 4507741  110 RVMANVRERQRTQSLNEAFAALRKIIPTLP----SDKLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd11431   2 RKTANARERDRMREINDAFEALRRAVPEYPvagkDGKLTKITTLRLAMNYIKALTDLL 59

basic helix-loop-helix (bHLH) domain found in scleraxis and similar proteins; Scleraxis, also termed SCX, or Class A basic helix-loop-helix protein 41 (bHLHa41), or Class A basic helix-loop-helix protein 48 (bHLHa48), is a bHLH transcription factor that is expressed in sclerotome limb bud cranial and body wall mesenchyme, pericardium and heart valves, ligaments and tendons. It is required for tendon formation ligaments, connective tissue, the diaphragm, and testis development. Scleraxis plays a central role in promoting fibroblast proliferation and matrix synthesis during the embryonic development of tendons.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd18951   4 QRHTANARERDRTNSVNTAFTALRTLIPTEPADrKLSKIETLRLASSYISHLGNVL 59

basic helix-loop-helix (bHLH) domain found in neurogenin (NGN) family; The NGN family includes three neural-specific bHLH transcription factors, NGN1-3, which may function at neuroblast selection genes during the development of several neuronal lineages. NGN-1, also termed Class A basic helix-loop-helix protein 6 (bHLHa6), or neurogenic basic-helix-loop-helix protein, or neurogenic differentiation factor 3 (NeuroD3), is a neural-specific bHLH transcription factor involved in the initiation of neuronal differentiation. NGN-2, also termed Class A basic helix-loop-helix protein 8 (bHLHa8), or protein atonal homolog 4 (ATOH4), is a neural-specific bHLH transcription factor required for sensory neurogenesis. NGN-3, also termed Class A basic helix-loop-helix protein 7 (bHLHa7), or protein atonal homolog 5 (ATOH5), is a neural-specific bHLH transcription factor expressed in the developing central nervous system and the embryonic pancreas. It is involved in neurogenesis and plays an important role in spermatogenesis.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd11428   1 RRLKANDRERNRMHNLNDALDALREVLPSFPDEtKLTKIETLRFAHNYIWALSETLK 57

basic helix-loop-helix (bHLH) domain found in neurogenin-2 (NGN-2) and similar proteins; NGN-2, also termed Class A basic helix-loop-helix protein 8 (bHLHa8), or protein atonal homolog 4 (ATOH4), is a neural-specific bHLH transcription factor required for sensory neurogenesis. It activates transcription by binding to the E box (5'-CANNTG-3').

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 4507741  107 QTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd19717   8 KTRRVKANNRERNRMHNLNAALDSLREVLPTFPEDaKLTKIETLRFAHNYIWALSETLR 66

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster helix loop helix protein 3B (dHLH3B) and similar proteins; Drosophila HLH3B is an uncharacterized bHLH transcription factor that belongs to the T-cell acute lymphocytic leukemia protein/ lymphoblastic leukemia-derived sequence (TAL/LYL) family.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd19708   1 RRMFTNSRERWRQQNVNGAFAELRKLVPTHPPDkKLSKNEILRLAIKYIRLLSNVLE 57

basic helix-loop-helix (bHLH) domain found in muscle, intestine and stomach expression 1 (MIST-1) and similar proteins; MIST-1, also termed Class A basic helix-loop-helix protein 15 (bHLHa15), or Class B basic helix-loop-helix protein 8 (bHLHb8), is a bHLH transcription factor expressed in pancreatic acinar cells and other serous exocrine cells. It is essential for cytoskeletal organization and secretory activity. It also functions as a potent endoplasmic reticulum (ER) stress-inducible transcriptional regulator. MIST-1 is capable of binding to E-box (CANNTG) motifs as a homodimer or a heterodimer with E-proteins (E12 and E47) to regulate transcription.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFL 159
Cdd:cd19711   1 RRLESNERERQRMHKLNNAFQALREVIPHVRAEkKLSKIETLTLAKNYIKSL 52

basic helix-loop-helix (bHLH) domain found in protein atonal homolog 1 (ATOH1) and similar proteins; ATOH1, also termed Class A basic helix-loop-helix protein 14 (bHLHa14), or helix-loop-helix protein hATH-1 (hATH1), or Math1, or Cath1, is a proneural bHLH transcription factor that is essential for inner ear hair cell differentiation. It dimerizes with E47 and activates E-box (CANNTG) dependent transcription. ATOH1 is a mammalian homolog of the Drosophila melanogaster gene atonal and mouse atonal homolog 1 (Math1).

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQS 165
Cdd:cd19713   6 RRLAANARERRRMHGLNHAFDQLRNVIPSFNNDkKLSKYETLQMAQIYINALSELLQG 63

basic helix-loop-helix (bHLH) domain found in protein atonal homologs ATOH1, ATOH7 and similar proteins; The family includes ATOH1 and ATOH7. ATOH1, also termed Class A basic helix-loop-helix protein 14 (bHLHa14), or helix-loop-helix protein hATH-1 (hATH1), or Math1, or Cath1, is a proneural bHLH transcription factor that is essential for inner ear hair cell differentiation. It dimerizes with E47 and activates E-box (CANNTG) dependent transcription. ATOH1 is a mammalian homolog of the Drosophila melanogaster gene atonal and mouse atonal homolog 1 (Math1). ATOH7, also termed Class A basic helix-loop-helix protein 13 (bHLHa13), or helix-loop-helix protein hATH-5 (hATH5), or Math5, is a bHLH transcription factor involved in the differentiation of retinal ganglion cells. The family also includes protein Amos (also termed absent MD neurons and olfactory sensilla protein, or reduced olfactory organs protein, or rough eye protein). It is a bHLH transcription factor that promotes multiple dendritic neuron formation in the Drosophila peripheral nervous system.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 4507741  110 RVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd11430   2 RLAANARERRRMNGLNRAFDQLRSVVPSIGNDkKLSKYETLQMAQIYIETLSELL 56

basic helix-loop-helix (bHLH) domain found in musculin, transcription factor 21 (TCF-21) and similar proteins; The family includes two bHLH transcription factors, musculin and transcription factor 21 (TCF-21). Musculin, also termed activated B-cell factor 1 (ABF-1), or Class A basic helix-loop-helix protein 22 (bHLHa22), is a bHLH transcription factor expressed in activated B lymphocytes. It acts as a transcription repressor capable of inhibiting the transactivation capability of TCF3/E47. Musculin may play a role in regulating antigen-dependent B-cell differentiation. The mouse homolog, musculin, is suggested to be a repressor of myogenesis that is expressed in developing muscle and in the spleen. TCF-21, also termed capsulin, or Class A basic helix-loop-helix protein 23 (bHLHa23), or epicardin, or podocyte-expressed 1 (Pod-1), is a bHLH transcription factor expressed specifically in mesodermally-derived cells that surround the epithelium of the developing gastrointestinal, genitourinary and respiratory systems during mouse embryogenesis. It may play a role in the specification or differentiation of one or more subsets of epicardial cell types.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd11423   1 QRNAANARERARMRVLSKAFSRLKTTLPWVPPDtKLSKLDTLRLAASYIAHLRQIL 56

basic helix-loop-helix (bHLH) domain found in neurogenin-1 (NGN-1) and similar proteins; NGN-1, also termed Class A basic helix-loop-helix protein 6 (bHLHa6), or neurogenic basic-helix-loop-helix protein, or neurogenic differentiation factor 3 (NeuroD3), is a neural-specific bHLH transcription factor involved in the initiation of neuronal differentiation. It activates transcription by binding to the E box (5'-CANNTG-3').

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 4507741  107 QTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd19716  15 KSRRVKANDRERNRMHNLNAALDELRSVLPSFPDDtKLTKIETLRFAHNYIWALSETLR 73

basic helix-loop-helix (bHLH) domain found in achaete-scute-like proteins, ASCL3-5, and similar proteins; This subfamily includes three ASCL family of transcription factors, ASCL-3, ASCL-4 and ASCL-5. ASCL-3, also termed Class A basic helix-loop-helix protein 42 (bHLHa42), or bHLH transcriptional regulator Sgn-1, or achaete-scute homolog 3 (ASH-3), is specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis. ASCL-4, also termed Class A basic helix-loop-helix protein 44 (bHLHa44), or achaete-scute homolog 4 (ASH-4), or Hash4, may be involved in skin development. ASCL-5, also termed Class A basic helix-loop-helix protein 47 (bHLHa47), or achaete-scute homolog 5 (ASH-5), is an uncharacterized bHLH transcription factor that is close related to ASCL-3 and ASCL-4.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 4507741  114 NVRERQRTQSLNEAFAALRKIIPTLPSDK-LSKIQTLKLAARYIDFLYQVL 163
Cdd:cd19724   6 NERERQRVRCVNEGYARLRRHLPLENKDKrLSKVETLRAAIRYIKHLQELL 56

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster protein dimmed and similar proteins; Dimmed, also termed DIMM, is a bHLH transcription factor that regulates neurosecretory (NS) cell function and neuroendocrine cell fate in Drosophila.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd19712   1 RRLESNERERMRMHSLNDAFQGLREVIPHVNAErKLSKIETLTLAKNYIKALTNVI 56

basic helix-loop-helix (bHLH) domain found in musculin and similar proteins; Musculin, also termed activated B-cell factor 1 (ABF-1), or Class A basic helix-loop-helix protein 22 (bHLHa22), is a bHLH transcription factor expressed in activated B lymphocytes. It acts as a transcription repressor capable of inhibiting the transactivation capability of TCF3/E47. Musculin may play a role in regulating antigen-dependent B-cell differentiation. The mouse homolog, musculin, is suggested to be a repressor of myogenesis that is expressed in developing muscle and in the spleen. Musculin heterodimerizes with products of the E2A gene.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 4507741  107 QTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQSDELDS 170
Cdd:cd19703   2 QSQRNAANARERARMRVLSKAFSRLKTSLPWVPPDtKLSKLDTLRLASSYIAHLRQLLQEDRYEN 66

basic helix-loop-helix (bHLH) domain found in transcription factor 21 (TCF-21) and similar proteins; TCF-21, also termed capsulin, or Class A basic helix-loop-helix protein 23 (bHLHa23), or epicardin, or podocyte-expressed 1 (Pod-1), is a bHLH transcription factor expressed specifically in mesodermally-derived cells that surround the epithelium of the developing gastrointestinal, genitourinary and respiratory systems during mouse embryogenesis. It may play a role in the specification or differentiation of one or more subsets of epicardial cell types.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 4507741  107 QTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQSDE 167
Cdd:cd19704   2 QVQRNAANARERARMRVLSKAFSRLKTTLPWVPPDtKLSKLDTLRLASSYIAHLRQILANDK 63

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor 2 (NeuroD2) and similar proteins; NeuroD2, also termed Class A basic helix-loop-helix protein 1 (bHLHa1), or NeuroD-related factor (NDRF), is a neuronal calcium-dependent bHLH transcription factor that induces neuronal differentiation and promotes neuronal survival. It plays a central role in thalamocortical synaptic maturation. NeuroD2 mediates calcium-dependent transcription activation by binding to E box-containing promoter.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 4507741  100 PQSYEELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLP-SDKLSKIQTLKLAARYIDFLYQVLQS 165
Cdd:cd19720  26 KARLERSKLRRQKANARERNRMHDLNSALDNLRKVVPCYSkTQKLSKIETLRLAKNYIWALSEILRS 92

basic helix-loop-helix (bHLH) domain found in helix-loop-helix protein 2 (HEN-2) and similar proteins; HEN-2, also termed nescient helix-loop-helix 2 (Nhlh2), or Class A basic helix-loop-helix protein 34 (bHLHa34), or nescient helix loop helix 2 (NSCL-2), is a neuron-specific bHLH transcription factor that may serve as DNA-binding protein and may be involved in the control of cell-type determination, possibly within the developing nervous system.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 4507741  116 RERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd19702  23 RERIRVEAFNLAFAELRKLLPTLPPDkKLSKIEILRLAICYISYLNHVL 71

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor 1 (NeuroD1) and similar proteins; NeuroD1, also termed Class A basic helix-loop-helix protein 3 (bHLHa3), is a neuronal bHLH transcription factor involved in the development and maintenance of the endocrine pancreas and neuronal elements. It acts as an essential regulator of glutamatergic neuronal differentiation. Loss of NeuroD1 causes ataxia, cerebellar hypoplasia, sensorineural deafness, and severe retinal dystrophy in mice.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 4507741  104 EELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLP-SDKLSKIQTLKLAARYIDFLYQVLQS 165
Cdd:cd19719  23 ERFKMRRMKANARERNRMHGLNAALDNLRKVVPCYSkTQKLSKIETLRLAKNYIWALSEILRS 85

basic helix-loop-helix (bHLH) domain found in Oligodendrocyte lineage genes (OLIG) family of transcription factors; The OLIG family includes three bHLH transcription factors, Oligo1-3, which are expressed in both the developing and mature central nervous system. Oligo1 and Oligo2 are expressed in a nervous tissue-specific manner, but Oligo3 is found mainly in non-neural tissues. Oligo (also known as Olig) have key roles in the specification of motor neurons, dorsal interneurons, and oligodendrocytes. Oligo1, also termed Class B basic helix-loop-helix protein 6 (bHLHb6), or Class E basic helix-loop-helix protein 21 (bHLHe21), promotes formation and maturation of oligodendrocytes, especially within the brain. Oligo2, also termed Class B basic helix-loop-helix protein 1 (bHLHb1), or Class E basic helix-loop-helix protein 19 (bHLHe19), or protein kinase C-binding protein 2, or protein kinase C-binding protein RACK17, is required for oligodendrocyte and motor neuron specification in the spinal cord, as well as for the development of somatic motor neurons in the hindbrain. It cooperates with OLIG1 to establish the MN progenitors (pMN) domain of the embryonic neural tube. Oligo3, also termed Class B basic helix-loop-helix protein 7 (bHLHb7), or Class E basic helix-loop-helix protein 20 (bHLHe20), is expressed in the ventricular zone of the dorsal alar plate of the hindbrain and involved in regulating the development of dorsal and ventral spinal cord. It may determine the distinct specification program of class A neurons in the dorsal part of the spinal cord and suppress specification of class B neurons. This family also includes two OLIG-related bHLH transcription factors, bHLHe22 and bHLHe23. bHLHe22, also termed Class B basic helix-loop-helix protein 5 (bHLHb5), or trinucleotide repeat-containing gene 20 protein, is a neural-specific transcriptional repressor that is expressed in both excitatory (unipolar brush cells) and inhibitory neurons (cartwheel cells) of the dorsal cochlear nucleus (DCN) during development. It is important for the proper development and/or survival of a number of neural cell types. bHLHe23, also termed Class B basic helix-loop-helix protein 4 (bHLHb4), is expressed in rod bipolar cells and is required for rod bipolar cell maturation. bHLHe23 have roles in spinal interneuron differentiation by mechanisms linked to the Notch signaling pathway. It modulates the expression of genes required for the differentiation and/or maintenance of pancreatic and neuronal cell types.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 4507741  110 RVMANVRERQRTQSLNEAFAALRKIIPTLPSD---KLSKIQTLKLAARYIDFLYQVLQS 165
Cdd:cd11429   1 RLKINSRERKRMHDLNSALDGLRSVMPYAQGPsvrKLSKIATLLLARNYILMLTQALEE 59

basic helix-loop-helix (bHLH) domain found in Class E basic helix-loop-helix protein bHLHe22, bHLHe23 and similar proteins; The family includes two OLIG-related bHLH transcription factors, bHLHe22 and bHLHe23. bHLHe22, also termed Class B basic helix-loop-helix protein 5 (bHLHb5), or trinucleotide repeat-containing gene 20 protein, is a neural-specific transcriptional repressor that is expressed in both excitatory (unipolar brush cells) and inhibitory neurons (cartwheel cells) of the dorsal cochlear nucleus (DCN) during development. It is important for the proper development and/or survival of a number of neural cell types. bHLHe23, also termed Class B basic helix-loop-helix protein 4 (bHLHb4), is expressed in rod bipolar cells and is required for rod bipolar cell maturation. bHLHe23 have roles in spinal interneuron differentiation by mechanisms linked to the Notch signaling pathway. It modulates the expression of genes required for the differentiation and/or maintenance of pancreatic and neuronal cell types.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 4507741  110 RVMANVRERQRTQSLNEAFAALRKIIPTLPSD---KLSKIQTLKLAARYIdfLYQVLQSDEL 168
Cdd:cd11468   1 RLSINARERRRMHDLNDALDDLRAVIPYAHSPsvrKLSKIATLLLAKNYI--LMQARAIEEL 60

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster achaete-scute complex (AS-C) proteins, achaete-scute-like proteins, ASCL1-2, and similar proteins; This subfamily includes Drosophila melanogaster AS-C proteins and two ASCL family of transcription factors, ASCL-1 and ASCL-2. Drosophila melanogaster AS-C proteins includes lethal of scute (also known as achaete-scute complex protein T3 or AST3), scute (also known as achaete-scute complex protein T4 or AST4), achaete (also known as achaete-scute complex protein T5 or AST5), and asense (also known as achaete-scute complex protein T8 or AST8). They are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system, as well as in sex determination and dosage compensation. ASCL-1, also termed Class A basic helix-loop-helix protein 46 (bHLHa46), or achaete-scute homolog 1 (ASH-1), or mammalian achaete scute homolog 1 (Mash1), is expressed in subsets of neural progenitors in both the central and peripheral nervous system. It plays a key role in neuronal differentiation and specification in the nervous system. ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete scute homolog 2 (Mash2), is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 4507741  114 NVRERQRTQSLNEAFAALRKIIPTLP-SDKLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd19723   6 NERERNRVKLVNLGFATLREHVPNGRaNKKMSKVETLRSAVEYIRQLQQLL 56

basic helix-loop-helix (bHLH) domain found in ovary, uterus and testis protein (OUT) family; The OUT family includes transcription factor 23 (TCF-23), transcription factor 24 (TCF-24) and similar proteins. TCF-23, also termed Class A basic helix-loop-helix protein 24 (bHLHa24), is a bHLH transcription factor that is essential for progesterone-dependent decidualization. The mouse homolog is also called ovary, uterus and testis protein (OUT), which is expressed predominantly in the reproductive organs such as the uterus, ovary and testis. It shows an Id-like inhibitory activity and functions as a negative regulator of bHLH factors through the formation of a functionally inactive heterodimeric complex. OUT inhibits the formation of TCF3 and MYOD1 homodimers and heterodimers, but lacks DNA binding activity. OUT is involved in the regulation or modulation of smooth muscle contraction of the uterus during pregnancy and particularly around the time of delivery. It also plays a role in the inhibition of myogenesis. Unlike typical bHLH factors, OUT proteins do not bind E-box (CANNTG) or N-box DNA sequences and inhibit DNA binding of homo- and heterodimers consisting of E12 and MyoD in gel mobility shift assays. TCF-24 is an uncharacterized bHLH transcription factor that shows high sequence similarity with TCF-23.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 4507741  116 RERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd11424   7 RERSRVRTLRTAFQSLQRALPAVPPDtKLSKLDVLLLASRYIAHLTRKL 55

basic helix-loop-helix (bHLH) domain found in transcription factor 24 (TCF-24) and similar proteins; TCF-24 is an uncharacterized bHLH transcription factor that shows high sequence similarity with TCF-23.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 4507741  116 RERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd19710   8 RERSRVQTLRSAFLELQRTLPSVPPDtKLSKLDVLVLATTYIAHLMRTL 56

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 4 (ASCL-4) and similar proteins; ASCL-4, also termed Class A basic helix-loop-helix protein 44 (bHLHa44), or achaete-scute homolog 4 (ASH-4), or Hash4, is a bHLH transcriptional regulator that may be involved in skin development.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 4507741  114 NVRERQRTQSLNEAFAALRKIIPTLPSDK-LSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd19746  13 NERERQRVRCVNEGYARLREHLPQELADKrLSKVETLRAAIDYIKHLQELLE 64

basic helix-loop-helix (bHLH) domain found in Class A basic helix-loop-helix protein 9 (bHLHa9) and similar proteins; bHLHa9, also termed Class F basic helix-loop-helix factor 42 (bHLHf42), is a bHLH transcription factor that plays an essential role in limb development.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 4507741  107 QTQRVMANVRERQRTQSLNEAFAALRKIIP-TLPSDKLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd18912   6 KARRVAANVRERKRILDYNQAFNALRLALKhDLGGKRLSKIATLRRAINRISALSLFL 63

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 2 (ASCL-2) and similar proteins; ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete scute homolog 2 (Mash2), is a bHLH transcription factor that is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 4507741  114 NVRERQRTQSLNEAFAALRKIIPTL-PSDKLSKIQTLKLAARYIDFLYQVL 163
Cdd:cd19743   8 NERERNRVKLVNLGFAALRQHVPQGgASKKMSKVETLRSAVEYIRALQRLL 58

basic helix-loop-helix (bHLH) domain found in oligodendrocyte transcription factors, Oligo2, Oligo3 and similar proteins; The family includes two bHLH transcription factors, Oligo2 and Oligo3. Oligo2, also termed Class B basic helix-loop-helix protein 1 (bHLHb1), or Class E basic helix-loop-helix protein 19 (bHLHe19), or protein kinase C-binding protein 2, or protein kinase C-binding protein RACK17, is required for oligodendrocyte and motor neuron specification in the spinal cord, as well as for the development of somatic motor neurons in the hindbrain. It cooperates with OLIG1 to establish the MN progenitors (pMN) domain of the embryonic neural tube. Oligo3, also termed Class B basic helix-loop-helix protein 7 (bHLHb7), or Class E basic helix-loop-helix protein 20 (bHLHe20), is expressed in the ventricular zone of the dorsal alar plate of the hindbrain and involved in regulating the development of dorsal and ventral spinal cord. It may determine the distinct specification program of class A neurons in the dorsal part of the spinal cord and suppress specification of class B neurons.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 4507741  110 RVMANVRERQRTQSLNEAFAALRKIIPTL--PS-DKLSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd19725   2 RLKINSRERKRMHDLNSALDGLREVMPYAhgPSvRKLSKIATLLLARNYILMLTNSLE 59

basic helix-loop-helix (bHLH) domain found in myogenic factor 5 (Myf-5) and similar proteins; Myf-5, also termed Class C basic helix-loop-helix protein 2 (bHLHc2), is a nuclear bHLH transcriptional activator that promotes transcription of muscle-specific target genes and plays a role in muscle specification and differentiation. It also acts as an RNA-binding protein which enhances Ccnd1/Cyclin D1 mRNA translation during myogenesis.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd18937   2 RRKAATMRERRRLKKVNQAFETLKRCTTSNPNQRLPKVEILRNAIRYIESLQDLLR 57

basic helix-loop-helix (bHLH) domain found in myogenin (MYOG) and similar proteins; MYOG, also termed Class C basic helix-loop-helix protein 3 (bHLHc3), or myogenic factor 4 (Myf-4), is a bHLH transcriptional activator that promotes transcription of muscle-specific target genes and plays a role in muscle differentiation, cell cycle exit and muscle atrophy.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQS 165
Cdd:cd18935   2 RRRAATLREKRRLKKVNEAFEALKRSTLLNPNQRLPKVEILRSAIQYIERLQALLSS 58

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 1 (ASCL-1) and similar proteins; ASCL-1, also termed Class A basic helix-loop-helix protein 46 (bHLHa46), or achaete-scute homolog 1 (ASH-1), or mammalian achaete scute homolog 1 (Mash1), is a neural-specific bHLH transcription factor that is expressed in subsets of neural progenitors in both the central and peripheral nervous system. It plays a key role in neuronal differentiation and specification in the nervous system.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 4507741  114 NVRERQRTQSLNEAFAALRKIIPTLPSDK-LSKIQTLKLAARYIDFLYQVLqsDELDSKMAS 174
Cdd:cd19742  10 NERERNRVKLVNMGFATLREHVPNGAANKkMSKVETLRSAVEYIRALQQLL--DEHDAVSAA 69

basic helix-loop-helix (bHLH) domain found in oligodendrocyte transcription factor 2 (Oligo2) and similar proteins; Oligo2, also termed Class B basic helix-loop-helix protein 1 (bHLHb1), or Class E basic helix-loop-helix protein 19 (bHLHe19), or protein kinase C-binding protein 2, or protein kinase C-binding protein RACK17, is a bHLH transcription factor that is required for oligodendrocyte and motor neuron specification in the spinal cord, as well as for the development of somatic motor neurons in the hindbrain. It cooperates with OLIG1 to establish the MN progenitors (pMN) domain of the embryonic neural tube.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 4507741  102 SYEELQTQRVMANVRERQRTQSLNEAFAALRKIIPTL--PS-DKLSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd18940   8 SEPELQQLRLKINSRERKRMHDLNIAMDGLREVMPYAhgPSvRKLSKIATLLLARNYILMLTNSLE 73

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in Max-like protein X (Mlx) family; Mlx, also termed Class D basic helix-loop-helix protein 13 (bHLHd13), or Max-like bHLHZip protein, or protein BigMax, or transcription factor-like protein 4, is a Max-like bHLHZip transcription regulator that interacts with the Max network of transcription factors. It forms a sequence-specific DNA-binding protein complex with some member of Mad family (Mad1 and Mad4) and Mondo family but not the Myc family and bind the E-box DNA to control transcription. The family also includes Saccharomyces cerevisiae INO4, which is a bHLH transcriptional activator of phospholipid synthetic genes (such as INO1, CHO1/PSS, CHO2/PEM1, OPI3/PEM2, etc.). It is required for de-repression of phospholipid biosynthetic gene expression in response to inositol deprivation in yeast.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 4507741  109 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQ 161
Cdd:cd11404   2 RRLNHVRSEKKRRELIKKGYDELCALVPGLDPQKRTKADILQKAADWIQELKE 54

basic helix-loop-helix (bHLH) domain found in Class E basic helix-loop-helix protein 23 (bHLHe23) and similar proteins; bHLHe23, also termed Class B basic helix-loop-helix protein 4 (bHLHb4), is an OLIG-related bHLH transcription factor that is expressed in rod bipolar cells and is required for rod bipolar cell maturation. bHLHe23 have roles in spinal interneuron differentiation by mechanisms linked to the Notch signaling pathway. It modulates the expression of genes required for the differentiation and/or maintenance of pancreatic and neuronal cell types.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 4507741  104 EELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSD---KLSKIQTLKLAARYIDFLYQVLQ 164
Cdd:cd18953   2 KEQRSLRLSINARERRRMHDLNDALDGLRSVIPYAHSPsvrKLSKIATLLLAKNYILMQAQALE 65