Figure 6.

Cdc42 GAPs regulate the location of the septin rings and formation of basal septin bands and caps. When grown pseudohyphal-inducing conditions the septin ring in parental BWP17 cells forms at the mother bud neck (A and D), whereas it forms within the germ tube in bem3Δ/Δ rga2Δ/Δ cells (B and D) in a Swe1-independent (C and D) and Rdi1-independent manner (D). Shortly after evagination a basal septin band, consisting of longitudinal bars, and an apical septin cap are visible in bem3Δ/Δ rga2Δ/Δ cells (E). Unbudded cells of the indicated genotypes were reinoculated into pseudohyphal-promoting conditions (pH 6.0, 36°C). Images in A–C and F were recorded in live cells 100 min after reinoculation; the image in D was recorded 40 min after evagination. (A–C) Cells counterstained with calcofluor white (CFW). (E) Cells counterstained with concanavalin A conjugated to Texas-Red (ConA Texas Red). For the quantification shown in D, cells were sampled after 100 min, and 100 cells analyzed for each genotype. Note for clarity in D, the full diploid genotype is not written out; all indicated deletions are homozygous. Bars, 5 μm (A–C) and 1 μm (E).