Proteomics analysis of hEPC1 polycomb protein complex in DNA damaged repair.

点击翻译按钮获取中文摘要

Eukaryotic genome is the tightly packed into the chromatin, a hierarchically organized complex of DNA and histone and nonhistone proteins. This packing represents a common obstacle for most of the DNA functions. Recently, we revealed that TIP60 histone acetylase complex involved in DNA repair and apoptosis. However, it remains unknown how TIP60 complex involves in DNA repair. To better understand the mechanism of TIP60 complex in DNA repair, TIP60 complex purifies from chromatin soluble fraction after DNA damage. As a result, enhancer of polycomb (hEPC1), the component of TIP60 complex, dissociated with the TIP60 complex. In order to clarify the role of hEPC1 in DNA repair,We purified the hEPC1 from HeLa after induction of DNA damage. hEPC1 was included in multiple protein complex. MS/MS analysis indicated that kinase, metyltransferase enzyme, histone H2AX, TIP60 histone acetylase and ubiquitin related proteins were identified as a component of hEPC1 complex. Metyltransferase activity was observed. In addition, Histone H2AX is phosphorylated after DNA damage. The phosphorylation of H2AX was inhibited in HeLa cells expressing siEPC RNA suggested that the hEPC1 complex includes kinase domain.