Biology

Richard D. Morgan
New England Biolabs, Inc., Ipswich, USA

Bacterial DNA methyltransferases (MTases) are most often part of Restriction-Modification systems that protect the bacterial host from parasitic DNA infection and regulate the exchange of genetic material between microorganisms. Solitary MTases with functions apart from restriction also are observed, such as the dam MTase of E. coli. Until recently, determining the specificity of DNA MTases has been relatively tedious, such that R-M systems were typically characterized through their endonuclease activity. However with the advent of Single-Molecule, Real-Time (SMRT) sequencing this situation has changed dramatically. It is now possible to identify the recognition sequence motif, individual base modified and specific form of modification produced by a MTase directly from SMRT sequence data. The analysis of methylation in complete, closed bacterial genome sequences from SMRT sequencing is now producing a wealth of new information about bacterial epigenetics, particularly for the previously underepresented Type I, Type ISP, Type IIG and Type III R-M systems. Here we report new findings from our bacterial methylome analyses.