Figure 1.
Dig1 and Dig2 regulate filamentous growth in naturally invasive diploids. (A) Loss of DIG1 and DIG2 enhance diploid pseudohyphal development. Strain JCY102 (MATa/MATα DIG+) (a and c) and its otherwise isogenic derivative, YLB503 (MATa/MATα dig1Δ/dig1Δ dig2Δ/dig2Δ) (b and d), were assayed for filament formation on plates containing either low nitrogen (low N) (a and b) or high nitrogen (high N) (c and d). Representative colonies, photographed after 3 days (low N) or 1 day (high N) of growth at 30°C, are shown. (B) Expression of the FRETy1-lacZ reporter. The strains described in A were transformed with plasmid YEpU-FTyZ and grown on low nitrogen plates for 48 hr at 30°C, and β-galactosidase specific activity (nmol per min per mg of protein) was measured. Values represent the average of measurements, made in duplicate, on protein extracts prepared from at least three transformants of each strain. Error bars indicate the standard deviation. Comparable results were obtained on high nitrogen plates (data not shown).