Tissue-specific repression of starvation and stress responses of the Neurospora crassa con-10 gene is mediated by RCO1

The Neurospora crassa con-10 gene is weakly expressed in mycelia but is ind uced approximately 1000-fold during macroconidiation. Studies of the promot er elements and trans-acting factors that regulate con-10 expression are ne eded to gain a detailed understanding of developmental regulation. The rco- 1 mutant displays a 10-fold elevated basal lever of expression of con-10, I n contrast to the wild type, con-10 expression in mycelia of the rco-1 muta nt was rapidly induced to high levels by starvation for carbon or nitrogen and by heat shock, Although con-10 is developmentally induced late in conid iation, con-10 was inducible by heat shock shortly after exposure of the wi ld-type mycelium to air. These findings support the view that RCO1 is a cel l type-specific repressor of con-10, We propose that inactivation of RCO1 a llows developing conidiophores to adjust the timing of con-10 induction in response to stress, (C) 1998 Academic Press.