Figure 7.—

Mutations that interfere with histone acetylation do not suppress spt5-242. (A) Loss of the SAGA subunit Spt8 decreases the viability of spt5-242 mutants. A strain containing spt5-242 was crossed to a strain lacking SPT8. The resulting diploid was transformed with a URA3 SPT5 plasmid and then followed through sporulation. The parental strains, a wild-type control, and three representative double mutants were selected and spotted to YPD and 5FOA and incubated at 30° for 2 days. (B) Mutation of H3K9 or H3K14 fails to suppress spt5-242, but mutation of H3K9/14/18/23 leads to enhanced spt5-242 phenotypes. SPT5 and spt5-242 strains carrying deletions of both histone H3–H4 loci and a URA3 HHT1-HHF1 plasmid were transformed with plasmids carrying the indicated histone H3 allele. Trp⁺ transformants were spotted directly to 5FOA and incubated at 30° for 2 days or 22° for 3 days.