InsP signaling mutants can uncouple the pseudohyphal response from growth in nitrogen-limiting conditions.

<p><b>(A)</b> Pseudohyphal growth phenotypes for InsP signaling mutants grown on standard media with normal levels of ammonium sulfate. The wild-type strain carries the empty pSGP47 vector so that all strains can be cultured uniformly. The wild-type filamentous strain exhibits no pseudohyphal growth under these conditions (“-”). To maintain consistency with other figures, pseudohyphal growth was measured here relative to the corresponding wild-type strain grown under low-nitrogen conditions that induce filamentation. By this comparison, as expected, the wild-type strain under normal nitrogen conditions does not exhibit pseudohyphal filamentation with a colony circumference ratio of roughly 0.6 compared against levels observed in low-nitrogen media. Scale bar, 500 μm. <b>(B)</b> Representative InsP profiles of the indicated strains grown in media with normal levels of ammonium sulfate. Fractions are indicated on the X-axis, with percent CPM shown on the Y-axis. Mean ratios of 5PP-InsP₅:1PP-InsP₅ with standard deviations are shown for the analyzed strains.