Fig. 3

A systematic genetic screen identifies H2A and H2B residues essential for the formation of spores in the SK1 genetic background. a Schematic of the strategy used for the genetic screen which systematically mutated H2A and H2B residues to alanine. > 250 mutant strains with at least three independent isolates per mutation have been created and validated by sequencing. The growth of strains with non-lethal mutations was first assessed on acetate, a non-fermentable carbon source. Then, their ability to form spores and the viability and stress resistance of these spores has been characterized. b Statistical analysis of the sporulation efficiency of the H2A H2B mutants. The severity of the sporulation defects is described using the following color code: a sporulation efficiency included within 0–20%, 20–60%, 60–80%, and 80–100% is represented in purple, red, orange, and grey, respectively. Lethal mutations are represented in black. This same color-coding is used throughout the figures of the manuscript for the SK1 background in accordance with Ref. [33]. c Localization of the substitution mutants with affected sporulation efficiency. Histone fold is represented on the top of each histone based on the yeast nucleosome structure [81]. d Venn diagram representing the repartition of the residues important for sporulation in SK1 and s288c genetic backgrounds. 49 mutations are associated with sporulation defects in both s288c and SK1 background, out of a total of 88 and 85, respectively. This enrichment is statistically significant (hypergeometric test, p value of 0.05)