title: A single CMT methyltransferase homolog is involved in CHG DNA methylation and development of Physcomitrella patens.
abstract: 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.
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, 69978, Tel-Aviv, Israel.
authors.forename: Chen
authors.initials: C
authors.lastname: Noy-Malka
authors.forename: Rafael
authors.initials: R
authors.lastname: Yaari
authors.forename: Rachel
authors.initials: R
authors.lastname: Itzhaki
authors.forename: Assaf
authors.initials: A
authors.lastname: Mosquna
authors.forename: Nitzan
authors.initials: N
authors.lastname: Auerbach Gershovitz
authors.forename: Aviva
authors.initials: A
authors.lastname: Katz
authors.forename: Nir
authors.initials: N
authors.lastname: Ohad
mesh_terms: D000595:Amino Acid Sequence; D005075:Biological Evolution; D019068:Bryopsida / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D019076:Transgenes
chemical_list: D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D004248:DNA (Cytosine-5-)-Methyltransferases; C112810:chromomethylase