DRUSE

Andrew Xiao and colleagues reported their findings (Nature 457, 57-62 ) recently (1 January 2009) about factors that are directly involved in regulating H2A.X.  In mammals, H2A.X Ser 139 phosphorylation (-H2A.X) occurs to reorganize chromatin in case of DNA double-strand breakage. Because the regulation of -H2A.X phosphorylation during the repair process remains unclear, they studied a new mechanism involving WSTF (Williams–Beuren syndrome transcription factor, also known as BAZ1B) – a component of the WICH complex (WSTF–ISWI ATP-dependent chromatin-remodelling complex). They showed that WSTF has intrinsic tyrosine kinase activity by means of a domain that shares no sequence homology to any known kinase fold. Furthermore, they demonstrated that WSTF phosphorylates Tyr 142 of H2A.X.