| The mammalian imitation SWI (ISWI) complexes are characterized by two ATPase subunits: Snf2h and Snf2l (1). Snf2h interacts with ATP-utilizing chromatin assembly and remodeling factor 1 (ACF1) to comprise the ACF chromatin-remodeling complex (1). ACF1 (BAZ1A) has distinct roles in development (2), regulation of chromatin structure (3), and DNA damage response (4,5). Different developmental stages dictate the expression of ACF1 in Drosophila, and alterations in ACF1 expression during Drosophila development leads to deviation from normal chromatin organization (2). ACF1 functions in heterochromatin formation during development and is involved in the initial establishment of diversified chromatin structures. In vivo studies demonstrate that heterochromatin protein 1 (HP1) binding to methylated lysine 9 of histone H3 is enhanced by the interaction of ACF1 with chromatin (6). Chromatin-remodeling factors are required during DNA damage in order to allow signaling molecules and damaging enzymes to access the site (4). Depletion of hACF1 increases apoptosis and vulnerability to radiation and compromises G2/M arrest activated in response to X-ray and UV exposure (4). Depletion of ACF1 also sensitizes cells to DNA double-stranded breaks (DSBs) and impairs DNA repair (5). Specifically, accumulation of Ku at DSBs sites may depend on the presence of ACF1 (5). |
