Dr. Xin-Jian He's lab revealed a new mechanism underlying the prevention of transcriptional silencing at heterochromatin regions

On June 8, 2016 ---- Dr. Xin-Jian He's lab published an article titled "The Arabidopsis acetylated histone-binding protein BRAT1 forms a complex with BRP1 and prevents transcriptional silencing" online in Nature Communications. This paper reported that a newly identified acetylated histone-binding protein is involved in the prevention of transcriptional silencing at heterochromatin regions.

Transposable elements and other repetitive DNA sequences are usually subject to DNA methylation and transcriptional silencing. However, anti-silencing mechanisms that promote transcription in these regions are not well understood. Here, we describe an anti-silencing factor, Bromodomain and ATPase domain-containing protein 1 (BRAT1), which we identified by a genetic screen in Arabidopsis thaliana. BRAT1 interacts with an ATPase domain-containing protein, BRP1 (BRAT1 Partner 1), and both prevent transcriptional silencing at methylated genomic regions. Although BRAT1 mediates DNA demethylation at a small set of loci targeted by the 5-methylcytosine DNA glycosylase ROS1, the involvement of BRAT1 in anti-silencing is largely independent of DNA demethylation. We demonstrate that the bromodomain of BRAT1 binds to acetylated histone, which may facilitate the prevention of transcriptional silencing. The study reveals a link between histone acetylation at methylated genomic regions and transcriptional anti-silencing, which may be conserved in eukaryotes.

Cui-Jun Zhang and Xiao-Mei Hou 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.

http://www.nature.com/ncomms/2016/160607/ncomms11715/full/ncomms11715.html