Genomic survey, gene expression analysis and structural modeling suggest diverse roles of DNA methyltransferases in legumes

PLoS One. 2014 Feb 25;9(2):e88947. doi: 10.1371/journal.pone.0088947. eCollection 2014.

Abstract

DNA methylation plays a crucial role in development through inheritable gene silencing. Plants possess three types of DNA methyltransferases (MTases), namely Methyltransferase (MET), Chromomethylase (CMT) and Domains Rearranged Methyltransferase (DRM), which maintain methylation at CG, CHG and CHH sites. DNA MTases have not been studied in legumes so far. Here, we report the identification and analysis of putative DNA MTases in five legumes, including chickpea, soybean, pigeonpea, Medicago and Lotus. MTases in legumes could be classified in known MET, CMT, DRM and DNA nucleotide methyltransferases (DNMT2) subfamilies based on their domain organization. First three MTases represent DNA MTases, whereas DNMT2 represents a transfer RNA (tRNA) MTase. Structural comparison of all the MTases in plants with known MTases in mammalian and plant systems have been reported to assign structural features in context of biological functions of these proteins. The structure analysis clearly specified regions crucial for protein-protein interactions and regions important for nucleosome binding in various domains of CMT and MET proteins. In addition, structural model of DRM suggested that circular permutation of motifs does not have any effect on overall structure of DNA methyltransferase domain. These results provide valuable insights into role of various domains in molecular recognition and should facilitate mechanistic understanding of their function in mediating specific methylation patterns. Further, the comprehensive gene expression analyses of MTases in legumes provided evidence of their role in various developmental processes throughout the plant life cycle and response to various abiotic stresses. Overall, our study will be very helpful in establishing the specific functions of DNA MTases in legumes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA / genetics*
  • DNA Methylation / genetics
  • DNA Modification Methylases / genetics*
  • Fabaceae / genetics*
  • Gene Expression / genetics*
  • Gene Expression Regulation, Plant / genetics*
  • Genome, Plant / genetics*
  • Genomics / methods
  • Methyltransferases / genetics*
  • Phylogeny
  • Plant Proteins / genetics

Substances

  • Plant Proteins
  • DNA
  • DNA Modification Methylases
  • Methyltransferases

Grants and funding

This work was funded by the Department of Science and Technology, Government of India, under the INSPIRE Faculty Award (grant number IFA-LSPA-05) to RG. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.