Chromodomain-helicase-DNA-binding domain (CHD) proteins have been identified in a variety of organisms.This family of proteins, which consists of nine members, has been divided into three separate subfamilies.All of the CHD proteins contain two tandem N-terminal chromodomains, a SWI/SNF-related ATPase domain, and a C-terminal DNA binding domain.CHD1 may play an important role in gene regulation.