The SET Domain Proteins SUVH2 and SUVH9 Are Required for Pol V Occupancy at RNA-Directed DNA Methylation Loci. Arabidopsis thaliana

Small RNA-induced transcriptional silencing at transposable elements and other DNA repeats is an evolutionarily conserved mechanism in plants, fungi, and animals. In Arabidopsis thaliana, an RNA-directed DNA methylation pathway is involved in transcriptional silencing. Noncoding RNAs produced by the plant-specific DNA-dependent RNA polymerase V are required for RNA-directed DNA methylation. A chromatin-remodeling complex was previously demonstrated to be required for the occupancy of DNA-dependent RNA polymerase V at RNA-directed DNA methylation loci. Our results suggest that two putative histone methyltransferases are inactive in their enzymatic activity and act as adaptor proteins to facilitate the recruitment of DNA-dependent RNA polymerase V to chromatin by associating with the chromatin-remodeling complex. In combination with previous studies, we propose that the inactive histone methyltransferases bind to methylated DNA, thereby linking DNA methylation to Pol V transcription at RNA-directed DNA methylation loci. Overall design: Compare the mRNA profiles of 2-week-old seedlings materials of mutants (nrpe1, suvh2suvh9 and dms3) to wild type Col by Illumina suquencing;