U.S. flag

An official website of the United States government

Format

Send to:

Choose Destination

Links from Nucleotide

    • Showing Current items.

    PTGES3 prostaglandin E synthase 3 [ Homo sapiens (human) ]

    Gene ID: 10728, updated on 3-Nov-2024

    Summary

    Go to the top of the page Help
    Official Symbol
    PTGES3provided by HGNC
    Official Full Name
    prostaglandin E synthase 3provided by HGNC
    Primary source
    HGNC:HGNC:16049
    See related
    Ensembl:ENSG00000110958 MIM:607061; AllianceGenome:HGNC:16049
    Gene type
    protein coding
    RefSeq status
    REVIEWED
    Organism
    Homo sapiens
    Lineage
    Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo
    Also known as
    P23; TEBP; cPGES
    Summary
    This gene encodes an enzyme that converts prostaglandin endoperoxide H2 (PGH2) to prostaglandin E2 (PGE2). This protein functions as a co-chaperone with heat shock protein 90 (HSP90), localizing to response elements in DNA and disrupting transcriptional activation complexes. Alternative splicing results in multiple transcript variants. There are multiple pseudogenes of this gene on several different chromosomes. [provided by RefSeq, Feb 2016]
    Expression
    Ubiquitous expression in ovary (RPKM 50.6), endometrium (RPKM 43.3) and 25 other tissues See more
    Orthologs
    mouse all
    NEW
    Try the new Gene table
    Try the new Transcript table

    Genomic context

    Go to the top of the page Help
    See PTGES3 in Genome Data Viewer
    Location:
    12q13.3; 12
    Exon count:
    9
    Annotation release Status Assembly Chr Location
    RS_2024_08 current GRCh38.p14 (GCF_000001405.40) 12 NC_000012.12 (56663349..56688284, complement)
    RS_2024_08 current T2T-CHM13v2.0 (GCF_009914755.1) 12 NC_060936.1 (56631338..56658334, complement)
    RS_2024_09 previous assembly GRCh37.p13 (GCF_000001405.25) 12 NC_000012.11 (57057133..57082068, complement)

    Chromosome 12 - NC_000012.12Genomic Context describing neighboring genes Neighboring gene NANOG-H3K27ac-H3K4me1 hESC enhancer GRCh37_chr12:57038866-57039576 Neighboring gene OCT4-NANOG-H3K27ac-H3K4me1 hESC enhancer GRCh37_chr12:57039577-57040285 Neighboring gene ATP synthase F1 subunit beta Neighboring gene small nucleolar RNA, C/D box 59B Neighboring gene small nucleolar RNA, C/D box 59A Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6511 Neighboring gene MPRA-validated peak1743 silencer Neighboring gene ATAC-STARR-seq lymphoblastoid silent region 4563 Neighboring gene RNA, 7SL, cytoplasmic 809, pseudogene Neighboring gene H3K27ac-H3K4me1 hESC enhancer GRCh37_chr12:57074705-57075584 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6512 Neighboring gene ATAC-STARR-seq lymphoblastoid silent region 4564 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6513 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6514 Neighboring gene NANOG-H3K27ac-H3K4me1 hESC enhancer GRCh37_chr12:57081953-57082478 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6515 Neighboring gene H3K27ac-H3K4me1 hESC enhancer GRCh37_chr12:57083531-57084056 Neighboring gene ReSE screen-validated silencer GRCh37_chr12:57094539-57094693 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6516 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6517 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6518 Neighboring gene nascent polypeptide associated complex subunit alpha Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6519 Neighboring gene DNA primase subunit 1 Neighboring gene Sharpr-MPRA regulatory region 96

    Genomic regions, transcripts, and products

    Go to the top of the page Help

    Go to nucleotide: Graphics FASTA GenBank

    Expression

    Go to the top of the page Help
    • Project title: HPA RNA-seq normal tissues HPA RNA-seq normal tissues
    • Description: RNA-seq was performed of tissue samples from 95 human individuals representing 27 different tissues in order to determine tissue-specificity of all protein-coding genes
    • BioProject: PRJEB4337
    • Publication: PMID 24309898
    • Analysis date: Wed Apr 4 07:08:55 2018

    Bibliography

    Go to the top of the pageHelp

    Related articles in PubMed

    1. The integration of multidisciplinary approaches revealed PTGES3 as a novel drug target for breast cancer treatment. Yin Q, et al. J Transl Med, 2024 Jan 20. PMID 38245717, Free PMC Article
    2. Computational aided mechanistic understanding of Camellia sinensis bioactive compounds against co-chaperone p23 as potential anticancer agent. Bharadwaj S, et al. J Cell Biochem, 2019 Nov. PMID 31257629
    3. A cytosolic heat shock protein 90 and co-chaperone p23 complex activates RIPK3/MLKL during necroptosis of endothelial cells in acute respiratory distress syndrome. Yu X, et al. J Mol Med (Berl), 2020 Apr. PMID 32072232
    4. The co-chaperone p23 promotes prostate cancer motility and metastasis. Cano LQ, et al. Mol Oncol, 2015 Jan. PMID 25241147, Free PMC Article
    5. Dysregulation of glucocorticoid receptor co-factors FKBP5, BAG1 and PTGES3 in prefrontal cortex in psychotic illness. Sinclair D, et al. Sci Rep, 2013 Dec 18. PMID 24345775, Free PMC Article

    See all (216) citations in PubMed

    GeneRIFs: Gene References Into Functions

    What's a GeneRIF?
    1. The integration of multidisciplinary approaches revealed PTGES3 as a novel drug target for breast cancer treatment.
      Title: The integration of multidisciplinary approaches revealed PTGES3 as a novel drug target for breast cancer treatment.
    2. Effect of PTGES3 on the Prognosis and Immune Regulation in Lung Adenocarcinoma.
      Title: Effect of PTGES3 on the Prognosis and Immune Regulation in Lung Adenocarcinoma.
    3. p23 and Aha1: Distinct Functions Promote Client Maturation.
      Title: p23 and Aha1: Distinct Functions Promote Client Maturation.
    4. Structure of Hsp90-p23-GR reveals the Hsp90 client-remodelling mechanism.
      Title: Structure of Hsp90-p23-GR reveals the Hsp90 client-remodelling mechanism.
    5. PTGES3 is a Putative Prognostic Marker in Breast Cancer.
      Title: PTGES3 is a Putative Prognostic Marker in Breast Cancer.
    6. A cytosolic heat shock protein 90 and co-chaperone p23 complex activates RIPK3/MLKL during necroptosis of endothelial cells in acute respiratory distress syndrome.
      Title: A cytosolic heat shock protein 90 and co-chaperone p23 complex activates RIPK3/MLKL during necroptosis of endothelial cells in acute respiratory distress syndrome.
    7. Structural elements in the flexible tail of the co-chaperone p23 coordinate client binding and progression of the Hsp90 chaperone cycle.
      Title: Structural elements in the flexible tail of the co-chaperone p23 coordinate client binding and progression of the Hsp90 chaperone cycle.
    8. Selective Autophagy Maintains the Aryl Hydrocarbon Receptor Levels in HeLa Cells: A Mechanism That Is Dependent on the p23 Co-Chaperone.
      Title: Selective Autophagy Maintains the Aryl Hydrocarbon Receptor Levels in HeLa Cells: A Mechanism That Is Dependent on the p23 Co-Chaperone.
    9. Computational aided mechanistic understanding of Camellia sinensis bioactive compounds against co-chaperone p23 as potential anticancer agent.
      Title: Computational aided mechanistic understanding of Camellia sinensis bioactive compounds against co-chaperone p23 as potential anticancer agent.
    10. This study evaluated the mechanism by which p23 triggers degradation of AHR, and the role of HSP90 in this process.
      Title: p23 protects the human aryl hydrocarbon receptor from degradation via a heat shock protein 90-independent mechanism.
    Submit: New GeneRIF Correction See all GeneRIFs (37)

    Phenotypes

    Go to the top of the page Help

    Review eQTL and phenotype association data in this region using PheGenI

    EBI GWAS Catalog

    Description
    New gene functions in megakaryopoiesis and platelet formation.
    EBI GWAS Catalog

    Variation

    Go to the top of the page Help

    See variants in ClinVar

    See studies and variants in dbVar

    See Variation Viewer (GRCh37.p13)

    See Variation Viewer (GRCh38)

    Genotypes

    HIV-1 interactions

    Go to the top of the page Help

    Replication interactions

    Interaction Pubs
    Knockdown of prostaglandin E synthase 3 (PTGES3) by siRNA inhibits the early stages of HIV-1 replication in 293T cells infected with VSV-G pseudotyped HIV-1 PubMed

    Protein interactions

    Protein Gene Interaction Pubs
    Rev rev HIV-1 Rev interacting protein, prostaglandin E synthase 3 (PTGES3), is identified by the in-vitro binding experiments involving cytosolic or nuclear extracts from HeLa cells PubMed
    Vpu vpu HIV-1 Vpu is identified to have a physical interaction with prostaglandin E synthase 3 (PTGES3; TEBP) in human HEK293 and/or Jurkat cell lines by using affinity tagging and purification mass spectrometry analyses PubMed

    Go to the HIV-1, Human Interaction Database

    Pathways from PubChem

    Go to the top of the page

    Interactions

    Go to the top of the page Help
    Products Interactant Other Gene Complex Source Pubs Description

    General gene information

    Go to the top of the page Help

    Markers

    Homology

    Gene Ontology Provided by GOA

    Function Evidence Code Pubs
    enables DNA polymerase binding IPI
    Inferred from Physical Interaction
    more info
    		 PubMed 
    enables Hsp90 protein binding IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    enables Hsp90 protein binding IPI
    Inferred from Physical Interaction
    more info
    		 PubMed 
    enables prostaglandin-E synthase activity IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    enables prostaglandin-E synthase activity IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    enables prostaglandin-E synthase activity TAS
    Traceable Author Statement
    more info
    		  
    enables protein binding IPI
    Inferred from Physical Interaction
    more info
    		 PubMed 
    enables protein-folding chaperone binding IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    enables telomerase activity IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    enables unfolded protein binding IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    Process Evidence Code Pubs
    involved_in chaperone cofactor-dependent protein refolding IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    involved_in chaperone-mediated protein complex assembly IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    involved_in chaperone-mediated protein complex assembly IMP
    Inferred from Mutant Phenotype
    more info
    		 PubMed 
    involved_in cyclooxygenase pathway TAS
    Traceable Author Statement
    more info
    		  
    involved_in fibroblast proliferation IEA
    Inferred from Electronic Annotation
    more info
    		  
    involved_in glycogen biosynthetic process IEA
    Inferred from Electronic Annotation
    more info
    		  
    involved_in lung saccule development IEA
    Inferred from Electronic Annotation
    more info
    		  
    involved_in nuclear receptor-mediated glucocorticoid signaling pathway IEA
    Inferred from Electronic Annotation
    more info
    		  
    involved_in positive regulation of telomere maintenance via telomerase IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    involved_in prostaglandin biosynthetic process IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    involved_in prostaglandin biosynthetic process IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    involved_in protein folding IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    involved_in protein stabilization IMP
    Inferred from Mutant Phenotype
    more info
    		 PubMed 
    involved_in signal transduction TAS
    Traceable Author Statement
    more info
    		 PubMed 
    involved_in skin development IEA
    Inferred from Electronic Annotation
    more info
    		  
    involved_in telomerase holoenzyme complex assembly IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    involved_in telomerase holoenzyme complex assembly IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    involved_in telomere maintenance TAS
    Traceable Author Statement
    more info
    		 PubMed 
    involved_in telomere maintenance via telomerase IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    acts_upstream_of_positive_effect telomere maintenance via telomerase IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    Component Evidence Code Pubs
    located_in chromosome, telomeric region IC
    Inferred by Curator
    more info
    		 PubMed 
    is_active_in cytosol IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    located_in cytosol TAS
    Traceable Author Statement
    more info
    		  
    located_in nucleoplasm TAS
    Traceable Author Statement
    more info
    		  
    located_in nucleus HDA PubMed 
    is_active_in nucleus IBA
    Inferred from Biological aspect of Ancestor
    more info
    		  
    part_of protein folding chaperone complex IDA
    Inferred from Direct Assay
    more info
    		 PubMed 
    part_of protein-containing complex IMP
    Inferred from Mutant Phenotype
    more info
    		 PubMed 
    part_of telomerase holoenzyme complex IDA
    Inferred from Direct Assay
    more info
    		 PubMed 

    General protein information

    Go to the top of the page Help
    Preferred Names
    prostaglandin E synthase 3
    Names
    Hsp90 co-chaperone
    cytosolic prostaglandin E synthase
    cytosolic prostaglandin E2 synthase
    progesterone receptor complex p23
    prostaglandin E synthase 3 (cytosolic)
    telomerase-binding protein p23
    unactive progesterone receptor, 23 kD
    NP_001269530.1
    NP_001269531.1
    NP_001269532.1
    NP_001269533.1
    NP_001269534.1
    NP_006592.3
    XP_005268633.1
    XP_006719262.1
    XP_011536075.1
    XP_011536076.1
    XP_016874205.1
    XP_054226794.1
    XP_054226795.1
    XP_054226796.1
    XP_054226797.1
    XP_054226798.1

    NCBI Reference Sequences (RefSeq)

    Go to the top of the page Help

    NEW Try the new Transcript table

    RefSeqs maintained independently of Annotated Genomes

    These reference sequences exist independently of genome builds. Explain

    These reference sequences are curated independently of the genome annotation cycle, so their versions may not match the RefSeq versions in the current genome build. Identify version mismatches by comparing the version of the RefSeq in this section to the one reported in Genomic regions, transcripts, and products above.

    mRNA and Protein(s)

    1. NM_001282601.2 → NP_001269530.1  prostaglandin E synthase 3 isoform b

      See identical proteins and their annotated locations for NP_001269530.1

      Status: REVIEWED

      Description
      Transcript Variant: This variant (2) lacks an alternate in-frame exon in the 3' coding region, compared to variant 1, resulting in an isoform (b) that is shorter than isoform a.
      Source sequence(s)
      AK298147, BC003005, BG927063, BP194632
      Consensus CDS
      CCDS61160.1
      UniProtKB/Swiss-Prot
      Q15185
      Related
      ENSP00000414892.2, ENST00000448157.6
      Conserved Domains (1) summary
      cd00237
      Location:3 → 109
      p23; p23 binds heat shock protein (Hsp)90 and participates in the folding of a number of Hsp90 clients, including the progesterone receptor. p23 also has a passive chaperoning activity and in addition may participate in prostaglandin synthesis.

    2. NM_001282602.2 → NP_001269531.1  prostaglandin E synthase 3 isoform c

      See identical proteins and their annotated locations for NP_001269531.1

      Status: REVIEWED

      Description
      Transcript Variant: This variant (3) lacks an in-frame exon in the central coding region, compared to variant 1, resulting in an isoform (c) that is shorter than isoform a.
      Source sequence(s)
      AK298160, BC003005, BG927063, BP194632
      Consensus CDS
      CCDS61159.1
      UniProtKB/Swiss-Prot
      Q15185
      Related
      ENSP00000405299.3, ENST00000414274.7
      Conserved Domains (1) summary
      cl00175
      Location:3 → 95
      alpha-crystallin-Hsps_p23-like; alpha-crystallin domain (ACD) found in alpha-crystallin-type small heat shock proteins, and a similar domain found in p23 (a cochaperone for Hsp90) and in other p23-like proteins.

    3. NM_001282603.2 → NP_001269532.1  prostaglandin E synthase 3 isoform d

      See identical proteins and their annotated locations for NP_001269532.1

      Status: REVIEWED

      Description
      Transcript Variant: This variant (4) lacks an in-frame exon in the central coding region, compared to variant 1, resulting in an isoform (d) that is shorter than isoform a.
      Source sequence(s)
      AK295208, BC003005, BG927063, BP194632
      Consensus CDS
      CCDS61158.1
      UniProtKB/Swiss-Prot
      Q15185
      Related
      ENSP00000402385.2, ENST00000436399.6
      Conserved Domains (1) summary
      cl00175
      Location:3 → 76
      alpha-crystallin-Hsps_p23-like; alpha-crystallin domain (ACD) found in alpha-crystallin-type small heat shock proteins, and a similar domain found in p23 (a cochaperone for Hsp90) and in other p23-like proteins.

    4. NM_001282604.2 → NP_001269533.1  prostaglandin E synthase 3 isoform e

      See identical proteins and their annotated locations for NP_001269533.1

      Status: REVIEWED

      Description
      Transcript Variant: This variant (5) contains an alternate exon in the 5' region, and initiates translation at an alternate start codon, compared to variant 1. The encoded isoform (e) has a distinct and longer N-terminus, compared to isoform a.
      Source sequence(s)
      BC003005, BG927063, BM541503, BP194632
      Consensus CDS
      CCDS73485.1
      UniProtKB/TrEMBL
      A0A087WYT3
      Related
      ENSP00000482075.1, ENST00000614328.4
      Conserved Domains (1) summary
      cd00237
      Location:7 → 113
      p23; p23 binds heat shock protein (Hsp)90 and participates in the folding of a number of Hsp90 clients, including the progesterone receptor. p23 also has a passive chaperoning activity and in addition may participate in prostaglandin synthesis.

    5. NM_001282605.2 → NP_001269534.1  prostaglandin E synthase 3 isoform f

      See identical proteins and their annotated locations for NP_001269534.1

      Status: REVIEWED

      Description
      Transcript Variant: This variant (6) lacks two alternate in-frame exons, compared to variant 1. The encoded isoform (f) is shorter than isoform a.
      Source sequence(s)
      BC003005, BG927063, BP194632, BU167210
      UniProtKB/Swiss-Prot
      Q15185
      Conserved Domains (1) summary
      cl00175
      Location:3 → 95
      alpha-crystallin-Hsps_p23-like; alpha-crystallin domain (ACD) found in alpha-crystallin-type small heat shock proteins, and a similar domain found in p23 (a cochaperone for Hsp90) and in other p23-like proteins.

    6. NM_006601.7 → NP_006592.3  prostaglandin E synthase 3 isoform a

      See identical proteins and their annotated locations for NP_006592.3

      Status: REVIEWED

      Description
      Transcript Variant: This variant (1) encodes isoform a.
      Source sequence(s)
      BC003005, BG927063, BP194632
      Consensus CDS
      CCDS31836.1
      UniProtKB/Swiss-Prot
      A8K7D0, B4DHP2, B4DP11, B4DP21, Q15185, Q8WU70
      Related
      ENSP00000262033.6, ENST00000262033.11
      Conserved Domains (1) summary
      cd00237
      Location:3 → 109
      p23; p23 binds heat shock protein (Hsp)90 and participates in the folding of a number of Hsp90 clients, including the progesterone receptor. p23 also has a passive chaperoning activity and in addition may participate in prostaglandin synthesis.

    RNA

    1. NR_104219.2 RNA Sequence

      Status: REVIEWED

      Description
      Transcript Variant: This variant (7) differs in the 5' terminal exon and uses an alternate splice site in the 3' region, compared to variant 1. This variant is represented as non-coding because uses of the 5' most expected translational start codon would render the transcript a candidate for nonsense-mediated mRNA decay (NMD).
      Source sequence(s)
      AC117378, AK098214, BC003005, BG927063, CA773263, DA556848
      Related
      ENST00000537473.2

    RefSeqs of Annotated Genomes: GCF_000001405.40-RS_2024_08

    The following sections contain reference sequences that belong to a specific genome build. Explain

    Reference GRCh38.p14 Primary Assembly

    Genomic

    1. NC_000012.12 Reference GRCh38.p14 Primary Assembly

      Range
      56663349..56688284 complement
      Download
      GenBank, FASTA, Sequence Viewer (Graphics)

    mRNA and Protein(s)

    1. XM_006719199.3 → XP_006719262.1  prostaglandin E synthase 3 isoform X5

      Conserved Domains (1) summary
      cl00175
      Location:7 → 99
      alpha-crystallin-Hsps_p23-like; alpha-crystallin domain (ACD) found in alpha-crystallin-type small heat shock proteins, and a similar domain found in p23 (a cochaperone for Hsp90) and in other p23-like proteins.

    2. XM_011537774.3 → XP_011536076.1  prostaglandin E synthase 3 isoform X4

      Conserved Domains (1) summary
      cd00237
      Location:7 → 113
      p23; p23 binds heat shock protein (Hsp)90 and participates in the folding of a number of Hsp90 clients, including the progesterone receptor. p23 also has a passive chaperoning activity and in addition may participate in prostaglandin synthesis.

    3. XM_005268576.6 → XP_005268633.1  prostaglandin E synthase 3 isoform X2

      See identical proteins and their annotated locations for XP_005268633.1

      Conserved Domains (1) summary
      cd00237
      Location:7 → 113
      p23; p23 binds heat shock protein (Hsp)90 and participates in the folding of a number of Hsp90 clients, including the progesterone receptor. p23 also has a passive chaperoning activity and in addition may participate in prostaglandin synthesis.

    4. XM_011537773.3 → XP_011536075.1  prostaglandin E synthase 3 isoform X3

      See identical proteins and their annotated locations for XP_011536075.1

      Conserved Domains (1) summary
      cd00237
      Location:3 → 109
      p23; p23 binds heat shock protein (Hsp)90 and participates in the folding of a number of Hsp90 clients, including the progesterone receptor. p23 also has a passive chaperoning activity and in addition may participate in prostaglandin synthesis.

    5. XM_017018716.2 → XP_016874205.1  prostaglandin E synthase 3 isoform X1

      UniProtKB/TrEMBL
      B3KUY2
      Conserved Domains (1) summary
      cd00237
      Location:7 → 113
      p23; p23 binds heat shock protein (Hsp)90 and participates in the folding of a number of Hsp90 clients, including the progesterone receptor. p23 also has a passive chaperoning activity and in addition may participate in prostaglandin synthesis.

    Alternate T2T-CHM13v2.0

    Genomic

    1. NC_060936.1 Alternate T2T-CHM13v2.0

      Range
      56631338..56658334 complement
      Download
      GenBank, FASTA, Sequence Viewer (Graphics)

    mRNA and Protein(s)

    1. XM_054370823.1 → XP_054226798.1  prostaglandin E synthase 3 isoform X5

    2. XM_054370822.1 → XP_054226797.1  prostaglandin E synthase 3 isoform X4

    3. XM_054370820.1 → XP_054226795.1  prostaglandin E synthase 3 isoform X2

    4. XM_054370819.1 → XP_054226794.1  prostaglandin E synthase 3 isoform X1

      UniProtKB/TrEMBL
      B3KUY2

    5. XM_054370821.1 → XP_054226796.1  prostaglandin E synthase 3 isoform X3

    Nucleotide Protein
    Heading Accession and Version
    Protein Accession Links
    GenPept Link UniProtKB Link
    Q15185.1 GenPept UniProtKB/Swiss-Prot:Q15185

    Gene LinkOut

    The following LinkOut resources are supplied by external providers. These providers are responsible for maintaining the links.

    Chemical Information
    Molecular Biology Databases
    Research Materials
    Tools
    Miscellaneous