Fig. 2.

Iqg1p and Tco89p share functions in rapamycin-sensitive growth, axial-bud-site selection and cytokinesis. (A,B) IQG1 or TCO89 null strains are temperature sensitive. Haploid wild-type (WT) and mutant cells were grown in YEPD to OD₆₀₀ 0.2, serially diluted into 96-well plates and the optical density was determined every 10 minutes overnight with a Bioscreen C plate reader (A) at 30°C and (B) at 37°C. (C) Iqg1p confers rapamycin-sensitive growth. Isogenic wild-type, iqg1Δ, tco89Δ, diploid (upper) and haploid (lower) strains were grown in YEPD to mid-log phase (OD₆₀₀=0.5), washed in sterile double-distilled water, serially diluted and plated on YEPD–agar for control (left) or on YEPD–agar containing 1.0 ng/ml rapamycin (right) and incubated at 30°C for 3 days then photographed with a Bio-Rad XRS imager. (D) Tco89p specifies axial budding. Isogenic haploid wild-type, iqg1Δ and tco89Δ strains were grown on YEPD, washed and stained with Calcofluor (which is a fluorescent dye specific for cell wall and bud-scar chitin), and photographed using a 100× oil immersion lens. The arrows denote additional buds from the same cell, indicating cytokinesis defects.