A single CMT methyltransferase homolog is involved in CHG DNA methylation and development of Physcomitrella patens

Chen Noy-Malka, Rafael Yaari, Rachel Itzhaki, Assaf Mosquna, Nitzan Auerbach Gershovitz, Aviva Katz*, Nir Ohad

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


C-5 DNA methylation is an essential mechanism controlling gene expression and developmental programs in a variety of organisms. Though the role of DNA methylation has been intensively studied in mammals and Arabidopsis, little is known about the evolution of this mechanism. The chromomethylase (CMT) methyltransferase family is unique to plants and was found to be involved in DNA methylation in Arabidopsis, maize and tobacco. The moss Physcomitrella patens, a model for early terrestrial plants, harbors a single homolog of the CMT protein family designated as PpCMT. Our phylogenetic analysis suggested that the CMT family is unique to embryophytes and its earliest known member PpCMT belongs to the CMT3 subfamily. Thus, P. patens may serve as a model to study the ancient functions of the CMT3 family. We have generated a ΔPpcmt deletion mutant which demonstrated that PpCMT is essential for P. patens protonema and gametophore development and is involved in CHG methylation as demonstrated at four distinct genomic loci. PpCMT protein accumulation pattern correlated with proliferating cells and was sub-localized to the nucleus as predicted from its function. Taken together, our results suggested that CHG DNA methylation mediated by CMT has been employed early in land plant evolution to control developmental programs during both the vegetative and reproductive haploid phases along the plant life cycle.

Original languageAmerican English
Pages (from-to)719-735
Number of pages17
JournalPlant Molecular Biology
Issue number6
StatePublished - Apr 2014

Bibliographical note

Funding Information:
Acknowledgments We thank Professors Tal Pupko, Eran Bacharach, Shaul Yalovsky and Daniel Chamovitz for critical reading and helpful comments. C.N.M and R.Y were supported in part by a matching Tel-Aviv University Deans doctoral fellowship and the Manna foundation. This research was supported by the Israeli Science Foundation Grant #767/09, and by the Israel Korea program # 3-824 financed by the Ministry of Science and Technology, both granted to N.O. Transgenic lines described in this study were deposited in the International Moss Stock Center (http://www.moss-stock-center.org/) with the accessions IMSC 40736, 40737, 40738 (χPpcmt 103, 157 and 281) and 40739, 40740 (PpCMT–GUS 7 and 8).


  • Chromomethylase
  • DNA methylation
  • Development
  • Epigenetic regulation
  • Physcomitrella patens
  • Transgene copy number


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