SepBCTF4 is required for the formation of DNA-damage-induced UvsCRAD51 foci in Aspergillus nidulans

Abstract

SepB is an essential, conserved protein required for chromosomal DNA metabolism in Aspergillus nidulans. Homologs of SepB include yeast Ctf4p and human hAnd-1. Molecular and bioinformatic characterization of these proteins suggests that they act as molecular scaffolds. Furthermore, recent observations implicate the yeast family members in lagging-strand replication and the establishment of sister-chromatid cohesion. Here, we demonstrate that SepB functions in the A. nidulans DNA damage response. In particular, analysis of double mutants reveals that SepB is a member of the UvsCRAD51 epistasis group. In accord with this prediction, we show that UvsC RAD51 forms DNA-damage-induced nuclear foci in a manner that requires SepB function. We also provide evidence that implicates SepB in sister-chromatid cohesion, thereby suggesting that cohesion may play a role in regulating the localization and/or assembly of UvsCRAD51 complexes. Copyright © 2005 by the Genetics Society of America.