Identification and characterization of novel proteins associated with CHD4

CHD (chromodomain helicase DNA binding protein) family is composed of nine members of chromatin remodeling factors that regulate chromatin structure in an ATP-dependent manner. Among them, CHD4 contributes to many basic cellular functions during development mainly through multiple proteins interacting with CHD4 including NuRD (nucleosome remodeling and deacetylase activities) complex, which contains histone deacetylase HDAC1/2. However, functions of CHD4 that are not mediated by NuRD complexes have also been found, implying the existence of unknown proteins that are associated with CHD4. In the present study, we generated CHD4 FLAG-tag knock-in cells in HeLa-S3 and HEK293T cells and sought proteins bound to CHD4 with the use of immunoprecipitation and liquid chromatography and tandem MS (LC-MS/MS) analysis. We found that LCORL (ligand dependent nuclear receptor corepressor like) and NOL4L (nucleolar protein 4 like) were reproducibly identified as a novel CHD4 interactors. RNA-sequencing analysis of HEK293T cells depleted of CHD4, LCORL, and NOL4L revealed consistent upregulation of genes related to the Notch pathway. Our results thus suggest that both NOL4L and LCORL may cooperate with CHD4 to suppress the Notch pathway in mammalian cells. Overall design: Transcriprional control regulated by CHD4, NOL4L, and LCORL