Derepression of stress genes in <i>cbf11Δ</i> cells is associated with H3K9 hyperacetylation in their promoters.

(A) Average gene profiles of total H3 (bottom panels) and acetylated H3K9 (top panels) occupancy at stress gene regions in WT and cbf11Δ cells. Genes upregulated as part of the core environmental stress response (CESR-UP, [9]) have been divided into those showing upregulation in untreated cbf11Δ cells (blue; n = 94, [15]) and the rest (red; n = 441). Average profile of all fission yeast genes is also shown for comparison (black; n = 6952). The curves represent mean RPM (reads per million mapped reads) values ± SEM; results from one representative biological replicate are shown. The promoter region is shaded. TSS—transcription start site. (B) Expression of the indicated stress genes in untreated WT, cbf11Δ, cut6OE and cbf11Δ cut6OE cells growing in YES medium was analyzed by RT-qPCR. Mean and SD values of three independent replicates are shown. One-sided Mann-Whitney U test was used to determine statistical significance. (C) Survival and growth under oxidative stress of WT, cbf11Δ, cut6OE and cbf11Δ cut6OE cultures spotted on YES plates containing the indicated concentrations of H2O2. (D) Expression of the indicated stress genes in untreated WT, cbf11Δ, mst1-L344S and cbf11Δ mst1-L344S cells growing in YES medium was analyzed by RT-qPCR. All cultures were shifted to 32°C (temperature restrictive for the mst1-L344S strain) prior to analysis. Mean and SD values of three independent replicates are shown. One-sided Mann-Whitney U test was used to determine statistical significance. (E) Expression of the indicated stress genes in untreated WT, cbf11Δ, gcn5Δ, and two independent isolates of cbf11Δ gcn5Δ cells growing in YES medium was analyzed by RT-qPCR. Mean and SD values of three independent replicates are shown. One-sided Mann-Whitney U test was used to determine statistical significance. (F) A model of the crosstalk between lipid metabolism and stress resistance. The left panel shows the WT situation; the right panel shows the situation in mutants with decreased synthesis of FA, with differences highlighted in blue. Hypothetical chromatin remodelers and/or histone modifiers are denoted with a question mark. Dashed lines represent speculative interactions. See Discussion for more details.