FIG 2.

Loss of H2A.Z suppresses the mitotic and repair defects of Smc5/6 mutants. (A) Alignment of the N-terminal sequences of S. pombe (Sp) and human (Hs) H2A.Z. Red lysines indicate residues subject to acetylation, and the valine-glycine substitution of pht1-36 is indicated above the alignment. Below are the positions of the αN-helix, and the beginning of the α1 helix of the histone fold (68). The plates under the alignment show growth at 25°C (5 days) and 30°C and 36°C (4 days). The vital dye Phloxin B stains dead cells red, and the residual colony formation of nse1-C216S top2-191 cells at 30°C shows spontaneous suppressors. Note that each pht1 allele suppressed the synthetic lethality of nse1-C216S top2-191 cells at 30°C. (B) Western blot of TCA-precipitated whole-cell extracts with anti-Pht1 and anti-β-tubulin antibodies. (C) Plates showing growth at 25°C (5 days) and 30°C and 36°C (4 days). The vital dye Phloxin B stains dead cells red, and the residual colony formation of smc6-74 top2-191 cells at 30°C represents spontaneous suppressors; all pht1 alleles suppressed the synthetic lethality of smc6-74 top2-191. (D and E) pht1Δ suppresses both the MMS (chronic exposure over 4 days at 30°C, spots are 10-fold serial dilutions) (D) and UV-C (colony formation) (E) sensitivities of smc6-74 in a ubc13-dependent manner.