Fig. 4.

Genetic relationship between histone substitutions and either spt2Δ, spt6-1004, or spt16-197. Tetrad analysis of hhts-K122A/hhts-K122A with spt2Δ (YS641 X YS642; a) or spt16-197 (YS640 X YJ780; b). Tetrads are vertical, where those circled indicate either spt2Δ or spt16-197 alleles alone, those surrounded by a triangle express either spt2Δ or spt16-197 in combination with hhts-K122A expressed at the HHT2/HHF2 locus, those surrounded by a square express hhts-K122A at both histone loci, those surrounded by a diamond express hhts-K122A at the HHT1/HHF1 locus, those which have a spore growing and are not indicated are WT for SPT2 or SPT16 and the histone loci, and those spores which do not grow are expressing either spt2Δ or spt16-197 and either hhts-K122A at both histone loci, or only at the HHT1/HHF1 locus. c Northern blot analysis examining the effect of single allele histone mutants on SER3, SRG1, and SCR1 (loading control). Total RNA was isolated from YS542, YS545, YS548, YS551, YS554, YS557, YS560, and YS563 that were grown to a density of 1–2 × 10⁷ cells/mL in YPD at 30 °C. d Northern blot analysis examining the effect of histone mutants in combination with spt2Δ, spt6-1004 or spt16-197 on SER3, SRG1, and SCR1 (loading control). Total RNA was isolated from FY346, FY2180, YJ804, YS404, YS409, YS417, YS428, YS591, YS594, YS597, YS600, YS601, YS604, YS606, YS609, YS612, and YS614 that were grown to a density of 1–2 × 10⁷ cells/mL in YPD at 30 °C. e, f Quantitation of Northern analyses. SRG1 (e) and SER3 (f) RNA levels for the histone mutants are normalized to the SCR1 loading control and are relative to the SRG1 and SER3 RNA levels measured in control HHTS-HHFS strains (arbitrarily set to 1). Each bar represents the mean ± SEM from three independent experiments strains generated by genetic crosses (YS591-YS619), except the spt16-197/hhts-Q120A strains, of which two independent strains were used, and the experiment was performed in triplicate (YS604, YS605)