title: MicroRNA binding sites in Arabidopsis class III HD-ZIP mRNAs are required for methylation of the template chromosome.
abstract: Dominant mutations in the Arabidopsis PHABULOSA (PHB) and PHAVOLUTA (PHV) transcription factor genes cause transformation of abaxial to adaxial leaf fates by altering a microRNA complementary site present in processed PHB and PHV mRNAs but not in the corresponding genomic DNA. phb-1d mutants accumulate excess PHB transcript throughout the leaf primordium, indicating defective regulation of PHB transcript synthesis and/or stability. We show that PHB and PHV coding sequences are heavily methylated downstream of the microRNA complementary site in most wild-type plant cells and that methylation is reduced in phb-1d and phv-1d mutants. Decreased methylation is limited to the chromosome bearing the dominant mutant allele in phb-1d heterozygotes. Low levels of methylation are detected in wt PHB DNA isolated from undifferentiated tissues. These results suggest a model in which the microRNA interacts with nascent, newly processed PHB mRNA to alter chromatin of the corresponding PHB template DNA predominantly in differentiated cells.
authors.affiliation: Program in Plant Breeding and Plant Genetics, University of Wisconsin, Madison, WI 53706, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Bao
authors.forename: Khar-Wai
authors.initials: KW
authors.lastname: Lye
authors.forename: M Kathryn
authors.initials: MK
authors.lastname: Barton
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D018899:CpG Islands; D019175:DNA Methylation; D018744:DNA, Plant / Q000187:drug effects; D005091:Exons; D005799:Genes, Dominant; D017343:Genes, Plant; D006579:Heterozygote; D035683:MicroRNAs / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D012333:RNA, Messenger / Q000145:classification / Q000378:metabolism*; D018749:RNA, Plant / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013447:Sulfites / Q000633:toxicity; D013698:Templates, Genetic; D014157:Transcription Factors / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D035683:MicroRNAs; D012333:RNA, Messenger; D018749:RNA, Plant; D013447:Sulfites; D014157:Transcription Factors