Figure 5. H2A.1 and Pol32 work in the same pathway during SCR, and H2A.1 is required for efficient BIR.

(A) Rates of spontaneous unequal SCR, assessed as in Figure 4D. Statistical deviation from wild-type was calculated using a Student’s t-test, **p<0.01. (B) Changes in CAG repeat length were assessed as in Figure 1C. Statistical deviation from wild-type was calculated by Fisher’s Exact Test: *p<0.05, ***p<0.001. (C) Assay to measure BIR at an HO-induced DSB. The first 400 bp of the URA3 gene (UR; right arm) is upstream of an HO cut site (stripes). Homology driven repair of the HO induced DSB can occur with the remaining 404 bp of the URA3 gene (A3; left arm) and if completed via BIR renders the cell URA⁺ and NAT^S (Anand et al., 2014). (D) Frequencies of BIR during repair of an HO-induced DSB; SEM of 4–9 replicates is shown (Supplementary file 7). Statistical deviation from wildtype was calculated using a Student’s t-test, ***p<0.001. (E) The type of repair induced by the HO DSB was evaluated by individually scoring all colonies for growth on YC-URA and YEPD+Nat. Colonies that were URA⁺ NAT^S are were repaired via BIR. Other types of possible repair events include gene conversion (URA⁺ NAT^R), non-homologous end-joining (URA^- NAT^R), and de novo telomere addition (URA^- NAT^S). Statistical analysis of BIR frequencies and repair types can be found in Supplementary file 7.

Figure 5—figure supplement 1. CAG fragility rates in the absence of Pol32.

(CAG)₈₅ repeat fragility was measured in hta1Δ, hta1-T126A and pol32Δ, and hta1Δ pol32Δ strains. Significant deviation from wild-type was measured by Student’s t-test: ***p<0.001 to WT. Values in Supplementary file 1.