The hSNF5 subunit of human SWI/SNF ATP-dependent chromatin remodeling complexes is a tumor suppressor that is inactivated in malignant rhabdoid tumors (MRTs). Here, we report that loss of hSNF5 function in MRT-derived cells leads to polyploidization and chromosomal instability. Re-expression of hSNF5 restored the coupling between cell cycle progression and ploidy checkpoints. In contrast, cancer-associated hSNF5 mutants harboring specific single amino acid substitutions exacerbated poly- and aneuploidization, due to abrogated chromosome segregation. We found that hSNF5 activates the mitotic checkpoint through the p16INK4a-cyclinD/CDK4-pRb-E2F pathway. These results establish that poly- and aneuploidy of tumor cells can result from mutations in a chromatin remodeler.

Chromatin, Chromosomal instability, hSNF5/INI1/Baf47/SmarcB1, Tumor suppressor,
Genes & Development
Department of Biochemistry

Vries, R.G.J, Bezrookove, V, Zuijderduijn, L.M.P, Kia, S.K, Houweling, A, Oruetxebarria, I, … Verrijzer, C.P. (2005). Cancer-associated mutations in chromatin remodeler hSNF5 promote chromosomal instability by compromising the mitotic checkpoint. Genes & Development, 19(6), 665–670. doi:10.1101/gad.335805