Chromodomain helicase DNA-binding protein 4 (CHD4) is an ATP dependent chromatin remodeler and a major subunit of the repressive NuRD complex . This complex plays key roles in transcriptional regulation and reorganization and maintenance of chromatin structure,as it targets pericentromeric heterochromatin and has recently been implicated in DNA damage repair,being rapidly recruited to DNA double strand breaks . CHD4 is a novel BRIT1 binding partner that regulates the HR repair process,which is a critical pathway of repairing DNA double strand breaks and plays an essential role in maintaining genomic integrity .