The chrome domain protein Chd1p from budding yeast is an ATP-dependent chromatin-modifying factor

CHD proteins are members of the chrome domain family, a class of proteins i nvolved in transcription, DNA degradation and chromatin structure. In highe r eukaryotes, there are two distinct subfamilies of CHD proteins: CHD1 and CHD3/4. Analyses carried out in vitro indicate that the CHD3/4 proteins may regulate transcription via alteration of chromatin structure. However, lit tle is known about the role of CHD proteins in vivo, particularly the CHD1 subfamily. To understand better the cellular function of CHD proteins, we i nitiated a study on the Chd1p protein from budding yeast. Using genomic DNA arrays, we identified genes whose expression is affected by the absence of Chd1p, A synthetic-lethal screen uncovered genetic interactions between SW I/SNF genes and CHD1. Biochemical experiments using Chd1p purified from yea st showed that it reconfigures the structure of nucleosome core particles i n a manner distinct from the SWI-SNF complex. Taken together, these results suggest that Chd1p functions as a nucleosome remodeling factor, and that C hd1p may share overlapping roles with the SWI-SNF complex to regulate trans cription.