ACF takes the driver's seat

Cryo-EM structure and functional analysis of the chromatin remodeler RSF

The RSF complex belongs to the ISWI chromatin-remodeling family and is composed of two subunits: RSF1 (remodeling and spacing factor 1) and SNF2h (sucrose nonfermenting protein 2 homolog). The RSF complex participates in nucleosome spacing and assembly, and subsequently promotes nucleosome maturation. Although SNF2h has been extensively studied in the last few years, the structural and functional properties of the remodeler RSF1 still remain vague. Here, a cryo-EM structure of the RSF-nucleosome complex is reported. The 3D model shows a two-lobe architecture of RSF, and the structure of the RSF-nucleosome (flanked with linker DNA) complex shows that the RSF complex moves the DNA away from the histone octamer surface at the DNA-entry point. Additionally, a nucleosome-sliding assay and a restriction-enzyme accessibility assay show that the RSF1 subunit may cause changes in the chromatin-remodeling properties of SNF2h. As a `nucleosome ruler', the results of an RSF-dinucleosome binding affinity test led to the proposal that the critical distance that RSF `measures' between two nucleosomes is about 24 base pairs.

Role of CHD1L in migration and invasion of human colon cancer cells

AIM: To examine the expression of chromodomain helicase/ATPase DNA binding protein 1-like gene (CHD1L) in colorectal cancer and to investigate its role in colorectal cancer cell migration and invasion.

METHODS: The expression of CHD1L in colorectal cancer and adjacent tissues was detected by fluorescence quantitative PCR and Western blot. The migration and invasion abilities of colorectal cancer cells overexpressing or underexpressing CHD1L were examined by scratch-wound migration and transwell invasion assays.

RESULTS: CHD1L mRNA and protein expression in colorectal cancer tissues was significantly higher than that in matched adjacent tissues. CHD1L in colon cancer cell lines also showed high expression. Transfection with CHD1L-shRNA in LOVO and DLD-1 cells significantly reduced the expression of CHD1L mRNA and protein, and inhibited the invasion and migration of cancer cells. In vivo experiments further showed that knockdown of CHD1L dramatically decreased the incidence of intrahepatic and lung metastases.

CONCLUSION: CHD1L is highly expressed in colorectal cancer tissues and cells, and it plays an important role in colorectal cancer invasion and migration. CHD1L may become a new target for treatment of colorectal cancer.