The genetic circuitry through which Hsf1 and Hsp90 regulate filamentation are distinct.

<p>a) Filaments induced by compromised Hsp90 function are not dependent on the transcription factors Rob1 or Efg1, but are dependent on the protease Kex2 and the cell cycle checkpoint protein Bub2. Cultures were grown in the absence or presence of 10 μM of geldanamycin (Gda) for 6.5 hours to inhibit Hsp90 function. b) Unlike filaments induced by compromised Hsp90 function, filaments induced by <i>HSF1</i> depletion are not dependent on Bub2 but are dependent on Efg1. Cultures were treated with no DOX, 0.1 μg/mL DOX (Low DOX), or 20 μg/mL DOX (High DOX) at 30°C. For both a) and b), blue outlines indicate that the homozygous deletion mutant of the morphogenetic regulator filaments to a comparable level as the non-mutant control and red outlines indicates that the mutant blocks filamentation.