In vivo association of CReMM/CHD9 with promoters in osteogenic cells.

Molecular mechanisms that control cell differentiation involve with chromatin remodeling activities. We recently identified Chromatin Related Mesenchymal Modulator (CReMM), a CHD protein expressed by mesenchymal cells. In this study, we analyzed CReMM expression on RNA and protein levels during embryonic development in mouse skeletal tissues. CReMM appears transiently during mesenchymal cell differentiation, being detected first in osteoprogenitors and declining in mature cells. A novel aspect of the study elaborates on in vivo association of CReMM with promoters in cells obtained by laser capture micro-dissection (LCM) technique from periosteum and endochondreal ossification regions. Using chromatin immunoprecipitation (ChIP), we proved that CReMM binds to skeletal tissue-specific promoters: CBFA1, biglycan, osteocalcin (OC), collagen-II, and myosin in a differential manner. The results imply that CReMM selectively interacts with analyzed promoters activated in the tissue at the appropriate time of development. The identification of CReMM and its tissue distribution and function provides an attractive clue for the study of transcriptional regulation of osteogenic cells' maturation.