A Rsc3/Rsc30 zinc cluster dimer reveals novel roles for the chromatin remodeler RSC in gene expression and cell cycle control

Chromatin remodeling complexes perform central roles in transcriptional reg ulation. Here, we identify Rsc3 and Rsc30 as novel components of the essent ial yeast remodeler RSC complex. Rsc3 and Rsc30 function requires their zin c cluster domain, a known site-specific DNA binding motif. RSC3 is essentia l, and rsc3 Ts mutants display a G2/M cell cycle arrest involving the spind le assembly checkpoint pathway, whereas rsc30 Delta mutants are viable and osmosensitive. Rsc3 and Rsc30 interact functionally and also physically as a stable RscS/Rsc30 heteromeric complex. However, DNA microarray analysis w ith rsc3 or rsc30 mutants reveals different effects on the expression level s of ribosomal protein genes and cell wall genes. We propose that Rsc3 and Rsc30 interact physically but have different roles in targeting or regulati ng RSC.