Article Figures & Data
Figures
- Fig. 1.
Role of Ash1 in filamentous growth. (A) Invasive growth. Haploid ASH1 [SC114(pRS426)], ash1Δ [SC112(pRS426)], and 2μm ASH1 [SC112(pAS163)] strains were grown on a YPD plate for 5 days. Photographs show patches before and after the plate was washed with water. (B) Pseudohyphal-colony formation. Diploid ASH1/ASH1[L5783(pRS426)], ash1Δ/ash1Δ [SC125(pRS426)], and 2μm ASH1 [SC125(pAS163)] strains were streaked out on nitrogen starvation medium (SLAD) and grown for 2.5 days at 30°C. Photographs show representative colonies of each strain.
- Fig. 2.
Effects of Ash1 overexpression on pseudohyphal-colony formation in strains with deletions of MAPK activation pathway components. (A) ste20Δ/ste20Δ (HLY492),ste11Δ/ste11Δ (HLY506), ste7Δ/ste7Δ(HLY351), and ste12Δ/ste12Δ (HLY352) diploid strains containing either vector (pRS426), 2μm ASH1(pAS163), or 2μm STE12 (pNC248) were grown on SLAD. (B) The ste20Δ/ste20Δ strain (HLY492) containing either vector (pRS426) or GAL-ASH1 (pNC543) was streaked out on nitrogen starvation medium containing galactose. Photographs show representative colonies of each strain after 2 (A) or 3 (B) days of growth at 30°C.
- Fig. 3.
Comparison of ASH1 and ash1Δ mutant strains for pseudohyphal-colony formation promoted by hyperactivation of the pathway. (A) ASH1/ASH1 (L5783) andash1Δ/ash1Δ (SC125) diploid strains containing 2μmSTE12 (pNC248) were grown on SLAD for 2 days at 30°C. (B)ASH1/ASH1 (L5783) and ash1Δ/ash1Δ (SC125) diploid strains containing GAL-STE11296–717 (pNC544) were grown on nitrogen starvation medium containing galactose for 1 day at 30°C. Photographs are of representative colonies.
- Fig. 4.
Synthetic pseudohyphal-colony phenotype ofash1Δ and ste12Δ mutants. ASH1/ASH1 STE12/STE12 [L5783(pRS426)], ash1Δ/ash1Δ STE12/STE12 [SC125(pRS426)], ASH1/ASH1 ste12Δ/ste12Δ [HLY352(pRS426)], and ash1Δ/ash1Δ ste12Δ/ste12Δ [SC137(pRS426)] diploid strains were patched onto SLAD and grown at 30°C for 4 days. Photographs show a representative region of an edge from each patch.
- Fig. 5.
Comparison of ash1Δ and ste12Δ single- or double-mutant strains for pseudohyphal-colony formation promoted by hyperactivation of the pathway. ASH1/ASH1 STE12/STE12 (L5783), ash1Δ/ash1Δ STE12/STE12(SC125), ASH1/ASH1 ste12Δ/ste12Δ (HLY352), andash1Δ/ash1Δ ste12Δ/ste12Δ (SC137) diploid strains containing either RAS2-V19 (pMW2) (A) or 2μmPHD1 (pCG37) (B) were grown on SLAD for 2 days at 30°C. Photographs are of representative colonies.
- Fig. 6.
Localization of GFP-Ash1 during pseudohyphal growth. Fluorescent (A and C) and differential interference contrast (B and D) views of cells are shown. (A and B) Diploid strain SC126, which is heterozygous for GFP-ASH1, grown on SLAD for 12 h. Insets show a mother-daughter pair of yeast form cells of the same diploid strain grown on SD-Ura. (C and D) Diploidash1Δ/ash1Δ strain SC125 with pNC513, which expressesGFP-ASH1 from the 2μm vector pRS426, grown on SLAD for 12 h. m, mother cell; d, daughter cell.
- Fig. 7.
Model for the pseudohyphal-response pathway. The diagram shows the postulated relationship of signal transmission components that function after the starvation signal(s) for induction of pseudohyphal growth. Arrows indicate activation or stimulation. Lines with bars indicate repression or inhibition. See the text for discussion of the evidence suggesting these relationships.
Tables
- Table 1.
S. cerevisiae strainsa
Strain Genotype Reference or source L5783 MAT a ura3-52 18 MATα ura3-52 HLY351 MAT a ura3-52 ste7Δ::LEU2 18 MATα ura3-52 ste7Δ::LEU2 HLY352 MAT a ura3-52 ste12Δ::LEU2 18 MATα ura3-52 ste12Δ::LEU2 HLY492 MAT a ura3-52 ste20Δ::LEU2 18 MATα ura3-52 ste20Δ::LEU2 HLY506 MAT a ura3-52 ste11Δ::LEU2 18 MATα ura3-52 ste11Δ::LEU2 SC110 MAT a ura3-52 ash1-Δ1::hisG-URA3-hisG This work MATα ura3-52 ASH1 SC112 MAT a ura3-52 ash1-Δ1::hisG-URA3-hisG This work SC113 MATα ura3-52 ash1-Δ1::hisG-URA3-hisG This work SC114 MAT a ura3-52 ASH1 This work SC121 MAT a ura3-52 ash1-Δ1::hisG This work SC122 MATα ura3-52 ash1-Δ1::hisG This work SC125 MAT a ura3-52 ash1-Δ1::hisG This work MATα ura3-52 ash1-Δ1::hisG SC126 MAT a ura3-52 GFP-ASH1::URA3::ash1-Δ1::hisG This work MATα ura3-52 ash1-Δ1::hisG SC127 MAT a ura3-52 ash1-Δ1::hisG leu2-Δ1 This work SC128 MATα ura3-52 ash1-Δ1::hisG leu2-Δ1 This work SC135 MAT a ura3-52 ash1-Δ1::hisG leu2-Δ1 ste12Δ::LEU2 This work SC136 MATα ura3-52 ash1-Δ1::hisG leu2-Δ1 ste12Δ::LEU2 This work SC137 MAT a ura3-52 ash1-Δ1::hisG leu2-Δ1 ste12Δ::LEU2 This work MATα ura3-52 ash1-Δ1::hisG leu2-Δ1 ste12Δ::LEU2 ↵a All strains are isogenic with strain Σ1278b, which is ho− and unable to switch mating types.
- Table 2.
Shapes and budding patterns of ASH1, 2μmASH1, and ash1Δ strainsa
Characteristic No. of cells of genotype: ASH1 2μm ASH1 ash1Δ Cell shapeb Round 44 55 124 Oval 109 72 67 Long 47 72 9 Long/(round + oval) 0.31 0.57 0.05 Budding patternc Bipolar 71 62 59 Unipolar 22 41 12 Unipolar/bipolar 0.3 0.7 0.2 ↵a Comparisons were made with cells from colonies (on SLAD) of diploid strain L5783 (ASH1/ASH1) transformed with the 2μm vector (pRS426) and diploid strain SC125 (ash1Δ/ash1Δ) transformed with the 2μm vector (pRS426) or the 2μm ASH1 plasmid (pAS163).
↵b Cell shape was assessed by visual estimation of the length-to-width ratio (l/w) for individual cells: round, l/w ∼ 1; oval, l/w = 1 to 2; long, l/w > 2.
↵c Budding pattern was assessed by the pattern of bud scars observed after staining with calcofluor: unipolar, two or more bud scars at the same pole; bipolar, one or more scars at opposite poles.
