Figure 1.

LRG1 is essential for hyphal tip extension. (A) wild type was grown on minimal media plates at 25°C (left, DIC image; right, Calcofluor White staining). Bar, 40 μm. (B) lrg-1(12-20) was grown on minimal media plates at 25°C and shifted for the indicated times to restrictive temperature to illustrate the cessation of tip extension with pointed, needle-like tips and the progressive hyperbranching of the mutant (phase-contrast images, top panel). Increased septation and abnormal chitin distribution was monitored by labeling with Calcofluor White (bottom panel). Bar, 40 μm. (C) Growth of the heterokaryotic lrg-1 deletion strain lrg-1⁺ + Δlrg-1 on minimal medium, medium containing fpa and histidine and medium containing benomyl and pantothenic acid (which forces the knockout nucleus to predominate), resulting in morphological defects identical to lrg-1(12-20) germinated at restrictive temperature. Bar, 7.5 μm.