Figure 4 .

The source of expression of H2B-A84D affects the resulting phenotypes. Isogenic strains from the A364a genetic background with the spt16-11 mutation (Table 1) were tested as in Figure 1, with the concentration of HU indicated. Panel A shows strains with the WT SPT16 allele and B shows strains with the spt16-11 mutation. Incubation times are listed in days to allow comparison of the level of growth at comparable times. In particular, htb1-A84D causes a weak Spt⁻ phenotype, as very little growth on medium lacking lysine is observed after 2 days but substantial growth is visible after 6 days. This is weak relative to the effect of spt16-11, which causes substantial growth on medium lacking lysine after 2 days. Both HTB1 and HTB2 are tagged in all cases, whether wild-type (+) or mutant (A84D). “∆” indicates deletion of both HTA2 and HTB2.