Reduced representation bisulfite sequencing for comparative high-resolution DNA methylation analysis.

Nucleic Acids Res
Authors
Keywords
Abstract

We describe a large-scale random approach termed reduced representation bisulfite sequencing (RRBS) for analyzing and comparing genomic methylation patterns. BglII restriction fragments were size-selected to 500-600 bp, equipped with adapters, treated with bisulfite, PCR amplified, cloned and sequenced. We constructed RRBS libraries from murine ES cells and from ES cells lacking DNA methyltransferases Dnmt3a and 3b and with knocked-down (kd) levels of Dnmt1 (Dnmt[1(kd),3a-/-,3b-/-]). Sequencing of 960 RRBS clones from Dnmt[1(kd),3a-/-,3b-/-] cells generated 343 kb of non-redundant bisulfite sequence covering 66212 cytosines in the genome. All but 38 cytosines had been converted to uracil indicating a conversion rate of >99.9%. Of the remaining cytosines 35 were found in CpG and 3 in CpT dinucleotides. Non-CpG methylation was >250-fold reduced compared with wild-type ES cells, consistent with a role for Dnmt3a and/or Dnmt3b in CpA and CpT methylation. Closer inspection revealed neither a consensus sequence around the methylated sites nor evidence for clustering of residual methylation in the genome. Our findings indicate random loss rather than specific maintenance of methylation in Dnmt[1(kd),3a-/-,3b-/-] cells. Near-complete bisulfite conversion and largely unbiased representation of RRBS libraries suggest that random shotgun bisulfite sequencing can be scaled to a genome-wide approach.

Year of Publication
2005
Journal
Nucleic Acids Res
Volume
33
Issue
18
Pages
5868-77
Date Published
2005
ISSN
1362-4962
URL
DOI
10.1093/nar/gki901
PubMed ID
16224102
PubMed Central ID
PMC1258174
Links
Grant list
R01 CA087869 / CA / NCI NIH HHS / United States
U54 HG003067 / HG / NHGRI NIH HHS / United States
5R01CA87869 / CA / NCI NIH HHS / United States
HG03067-02 / HG / NHGRI NIH HHS / United States