SRE3-independent effects of Swi2 on donor choice.

<p>(A) Representation of the mating-type region showing the probe (<i>Dde</i>I-<i>Nsi</i>I fragment) and restriction sites used for the Southern blots in (C). (B) Iodine staining of sporulated colonies with indicated genotypes. Dark staining reflects efficient switching. Light staining indicates a switching defect that can be either asymmetric towards a preferred mating-type (no staining at colony junctions) or inefficient in both directions (staining at colony junctions). (C) Southern blots of genomic DNA digested with <i>Dde</i>I and hybridized to the <i>Dde</i>I-<i>Nsi</i>I probe shown in (A), for nine independent cultures of <i>h⁹⁰ swi2</i>⁺: 968 (1–9); <i>h⁹⁰ swi2Δ</i>: TP133 (10–18); <i>SRE3Δ swi2</i>⁺: TP75 (19–27); <i>SRE3Δ swi2Δ</i>: TP157 (28–36). (D) Quantification of <i>mat1</i> content estimated from the Southern blots shown in (C). P/(P+M) ratios are plotted as % P cells. (E) Independent measurement of cell type ratios by fluorescence microscopy using a dual reporter system, YFP under control of the M-specific <i>mfm3</i> promoter and CFP under control of the P-specific <i>map2</i> promoter. M cells are yellow and P cells cyan. <i>h⁹⁰ swi2</i>⁺: TP220; <i>SRE3Δ swi2</i>⁺: TP270. Cell counts from fluorescence microscopy are presented in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003762#pgen.1003762.s006" target="_blank">Table S3</a>. Effects of Swi5 on donor choice are presented in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003762#pgen.1003762.s001" target="_blank">Figure S1</a>. All Southern blot quantifications are summarized in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003762#pgen.1003762.s002" target="_blank">Figure S2</a>.