Research News
Dr. Xin Jian He's article discovers a putative SU(VAR)3-9-like histone methyltransferase SUVR2 in Arabidopsis.
On Nov 25, 2014,Dr. Xin-Jian He's lab published an article titled "SUVR2 is involved in transcriptional gene silencing by associating with SNF2-related chromatin-remodeling proteins in Arabidopsis" in Cell Research. This paper demonstrates that a putative histone methyltransferase SUVR2 forms a complex with its homolog SUVR1 and associates with three chromatin-remodeling proteins,thereby affecting DNA methylation and transcriptional gene silencing in a novel mechanism.
The SU(VAR)3-9-like histone methyltransferases usually catalyze repressive histone H3K9 methylation and are involved in transcriptional gene silencing in eukaryotic organisms. We identified a putative SU(VAR)3-9-like histone methyltransferase SUVR2 by a forward genetic screen and demonstrated that it is involved in transcriptional gene silencing at genomic loci targeted by RNA-directed DNA methylation (RdDM). We found that SUVR2 has no histone methyltransferase activity and the conserved catalytic sites of SUVR2 are dispensable for the function of SUVR2 in transcriptional silencing. SUVR2 and its close homolog SUVR1 form a complex and associate with three previously uncharacterized SNF2-related chromatin-remodeling proteins CHR19, CHR27, and CHR28. SUVR2 was thought to be a component in the RNA-directed DNA methylation pathway. We demonstrated that SUVR2 contributes to transcriptional gene silencing not only at a subset of RdDM target loci but also at many RdDM-independent target loci. Our study suggests that the involvement of SUVR2 in transcriptional gene silencing is related to nucleosome positioning mediated by its associating chromatin-remodeling proteins.
Dr. Yong-Feng Han, a postdoctoral scholar, and Kun Dou, a PhD student from the He lab, are the co-first authors of the paper. Dr. Xin-Jian He from National Institute of Biological Sciences is the corresponding author. The study was supported by the 973 project of Chinese Ministry of Science and Beijing Municipal Government.
