Fig 5.

Loss of γH2A or Brc1 increases TBZ sensitivity in cells lacking the serine-121 site in histone H2A that is phosphorylated by Bub1. (A) Histone H2A mutants lacking the γH2A site (htaAQ [hta1-S129A hta2-S128A]) or the Bub1 phosphorylation site (htaSA [hta1-S121A hta2-S121A]) alone, or in combination (htaSA.AQ), or with brc1Δ were tested with TBZ or the indicated genotoxins. Cells were incubated at 30°C for 2 days. (B) Phosphorylation of histone H2A at serine-121 is not required for localization of Brc1 at centromeres. ChIP analysis of Brc1-GFP in cells treated with 12 mM HU for 4 h. Enrichment was calculated relative to the act1 locus (see Materials and Methods).