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SRX21542011: GSM7746911: L1633-Control_MS47_dSMF_EM-seq; Saccharomyces cerevisiae; Candida albicans; OTHER
1 ILLUMINA (NextSeq 550) run: 480,343 spots, 36.5M bases, 15.3Mb downloads

External Id: GSM7746911_r1
Submitted by: Genetics, Stanford University
Study: Genome-wide distribution of 5-hydroxymethyluracil and chromatin accessibility in the Breviolum minutum genome
show Abstracthide Abstract
In dinoflagellates, the most unique and divergent nuclear organization among the known diversity of eukaryotes has evolved. The list of highly unusual features of dinoflagellate nuclei and genomes is long -- permanently condensed liquid crystalline chromosomes, in which histones are not the main packaging component, genes organized as very long unidirectional gene arrays, general absence of transcriptional regulation, high abundance of the otherwise very rare DNA modification 5-hydroxymethyluracil (5-hmU), and many others. Most of these fascinating properties were originally identified in the 1970s and 1980s but have received very little attention in recent decades using modern genomic tools. In this work, we address some of the outstanding questions regarding dinoflagellate genome organization by mapping the genome-wide distribution of 5-hmU (using both immunoprecipitation-based and basepair-resolution chemical mapping approaches) and of chromatin accessibility in the genome of the dinoflagellate Breviolum minutum. We find that the 5-hmU modification is preferentially enriched over certain classes of repetitive elements, and also often coincides with the boundaries between gene arrays. It is generally anti-correlated with chromatin accessibility, the levels of which are lower in those regions. We discuss the potential roles of 5-hmU in the functional organization of dinoflagellate genomes and its relationship to the transcriptional landscape of gene arrays. Overall design: ATAC-seq in B. minutum; mapping of 5-hmU in B. minutum using MeDIP-seq and chemical mapping; SMF and ATAC-seq on yeast cells exogenously expressing various dinoflagellate DVNP proteins
Sample: L1633-Control_MS47_dSMF_EM-seq
SAMN37205249 • SRS18751410 • All experiments • All runs
Library:
Name: GSM7746911
Instrument: NextSeq 550
Strategy: OTHER
Source: GENOMIC
Selection: other
Layout: PAIRED
Construction protocol: Yeast SMF experiments were carried out as follows. A 1:1 mixture of S. cerevisiae cells expression DVNPs and Candida albicans cells (used as a control for normalization) amounting to a total of 2.5×108 cells was used as input. Cells in log phase (OD660 ≤ 1.0) were first centrifuged at 13,000 rpm for 1 minute, then washed with 100 µL Sorbitol Buffer(1.4 M Sorbitol, 40 mM HEPES-KOH pH 7.5, 0.5 mM MgCl2), and centrifuged again at 13,000 rpm for 1 minute. Cells were then spheroplasted by resuspending in 200 µL Sorbitol Buffer with DTT added at a final concentration of 10 mM and 0.5 mg/mL 100T Zymolase, followed by incubating for 5 minutes at 30◦C at 300 rpm in a Thermomixer. The pellet was centrifuged for 2 minutes at 5,000 rpm, washed in 100 µL Sorbitol Buffer, and centrifuged again at 5,000 rpm for 2 minutes. Cells were then resuspended in 100 µL ice-cold Nuclei Lysis Buffer (10 mM Tris pH 7.4, 10 mM NaCl, 3 mM MgCl2, 0.1 mM EDTA, 0.5% NP-40) and incubated on ice for 10 minutes. Nuclei were then centrifuged at 5000 rpm for 5 min at 4◦C, resuspended in 100 µL cold Nuclei Wash Buffer (10 mM Tris pH 7.4, 10 mM NaCl, 3 mM MgCl2, 0.1 mM EDTA), and centrifuged again at 5,000 rpm for 5 min at 4◦C. Finally, nuclei were resuspended in 100 µL M.CviPI Reaction Buffer (50 mM Tris-HCl pH 8.5, 50 mM NaCl, 10 mM DTT). Nuclei were then first treated with M.CviPI (GpC methyltransferase) by adding 200 U of M.CviPI (NEB), SAM at 0.6 mM and sucrose at 300 mM, and incubating at 30◦C for 7.5 min. After this incubation, 128 pmol SAM and another 100 U of enzymes were added, and a further incubation at 30◦C for 7.5 min was carried out. Immediately after, M.SssI treatment (CpG methyltransferase) followed, by adding 60 U of M.SssI (NEB), 128 pmol SAM, MgCl2 at 10 mM and incubation at 30◦C for 7.5 min. The reaction was stopped by adding an equal volume of Stop Buffer (20 mM Tris-HCl pH 8.5, 600 mM NaCl, 1% SDS, 10 mM EDTA). HMW DNA was isolated using the MagAttract HMW DNA Kit (Qiagen; cat # 67563) following the manufacturer's instructions. Enzymatically labeled DNA was then sheared on a Covaris E220 and converted into sequencing libraries following the EM-seq protocol, using the NEBNext Enzymatic Methyl-seq Kit (NEB, Cat # E7120L).
Runs: 1 run, 480,343 spots, 36.5M bases, 15.3Mb
Run# of Spots# of BasesSizePublished
SRR25820247480,34336.5M15.3Mb2023-10-19

ID:
29025653

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