Source: School of Life Sciences
Written by: School of Life Sciences
Edited by: Wang Dongmei

Dr. Zhou Songyang and his colleagues published an article entitled “The Daxx/Atrx Complex Protects Tandem Repetitive Elements during DNA Hypomethylation by Promoting H3K9 Trimethylation” on September’s issue of Cell Stem Cell (impact factor IF:22.3) , a renowned international journal in the field of stem cells.

During the long process of evolution, the mammalian genome formed a number of transposable elements featured with repetitive sequence due to viral invasions. Although these transposable elements enriched the source of genetic material, their expression and random integration could lead to gene mutations of specific individuals, causing cancer or other mortal diseases. In somatic cells, the expression of transposable elements can be repressed by DNA methylation. But in other important cells such as embryonic stem cells, germline stem cells and early embryonic cells, the activity of DNA methyltransferases and the level of methylation in genome is relatively low. Why the aberrant high expression and random integration doesn’t occur to these transposable elements without the protection of DNA methylation? Dr. Zhou Songyang and his colleagues have conducted study on this subject and found that in the cells of low DNA methylation, the Daxx/Atrx-protein complexes is transferred to the repetitive sequences of transposable elements to recruit histone methyltransferase Suv39h, which in turn mediated histone H3K9 trimethylation to ensure specific silencing of these repetitive sequences. It effectively prevented the gene mutations triggered by random integration of transposable elements. The result of the study revealed a new mechanism of specific histone modification in genomic stability control.

The research team of Stem Cells and Functional Genomics led by Dr. Zhou Songyang is committed to exploring the molecular mechanisms of human aging, regeneration and cancer pathogenesis. Dr. Zhou Songyang has so far published more than 110 SCI papers on different internationally renowned journals including Nature, Science, Cell, etc., with a total citations of over 11,380 times and a H-index of 52 in 2015.