An early cellular response to the occurrence of DNA double-strand breaks in mammals is the phosphorylation of the specialized histone variant H2A.X at Ser 139. The chromatin remodelling factor WSTF is found to phosphorylate H2A.X at another site, Tyr 142. Tyrosine phosphorylation has not been observed previously on histones.
- Andrew Xiao
- Haitao Li
- C. David Allis
