Genome-wide identification of 5-methylcytosine sites in bacterial genomes by high-throughput sequencing of MspJI restriction fragments

PLoS One. 2021 May 11;16(5):e0247541. doi: 10.1371/journal.pone.0247541. eCollection 2021.

Abstract

Single-molecule Real-Time (SMRT) sequencing can easily identify sites of N6-methyladenine and N4-methylcytosine within DNA sequences, but similar identification of 5-methylcytosine sites is not as straightforward. In prokaryotic DNA, methylation typically occurs within specific sequence contexts, or motifs, that are a property of the methyltransferases that "write" these epigenetic marks. We present here a straightforward, cost-effective alternative to both SMRT and bisulfite sequencing for the determination of prokaryotic 5-methylcytosine methylation motifs. The method, called MFRE-Seq, relies on excision and isolation of fully methylated fragments of predictable size using MspJI-Family Restriction Enzymes (MFREs), which depend on the presence of 5-methylcytosine for cleavage. We demonstrate that MFRE-Seq is compatible with both Illumina and Ion Torrent sequencing platforms and requires only a digestion step and simple column purification of size-selected digest fragments prior to standard library preparation procedures. We applied MFRE-Seq to numerous bacterial and archaeal genomic DNA preparations and successfully confirmed known motifs and identified novel ones. This method should be a useful complement to existing methodologies for studying prokaryotic methylomes and characterizing the contributing methyltransferases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5-Methylcytosine / chemistry
  • 5-Methylcytosine / isolation & purification*
  • Bacteria / genetics
  • DNA / genetics
  • DNA Methylation / genetics*
  • DNA Restriction Enzymes / genetics
  • Epigenomics*
  • Genome, Bacterial / genetics*
  • High-Throughput Nucleotide Sequencing
  • Methyltransferases / genetics
  • Sequence Analysis, DNA

Substances

  • 5-Methylcytosine
  • DNA
  • Methyltransferases
  • DNA Restriction Enzymes

Grants and funding

New England Biolabs provided support in the form of salaries for authors BPA, AF, and RJR, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.