An adenylyl cyclase, CyaA, of XXXX functions in signal transduction during osmotic stress.

@entity1522 @entity1472 @entity1219 @entity4986 @entity969 @entity1919 @entity1473
An adenylyl cyclase gene (cyaA) present upstream of an osmosensor protein gene (mokA) was isolated from @entity4986 . cyaA encoded a polypeptide of 843 @entity1522 with a predicted molecular mass of 91,187 Da. The predicted cyaA gene product had structural similarity to the receptor-type adenylyl cyclases that are composed of an @entity1472 -terminal sensor domain and a @entity1473 -terminal catalytic domain of adenylyl cyclase. In reverse transcriptase PCR experiments, the transcript of the cyaA gene was detected mainly during development and spore germination. A cyaA mutant, generated by gene disruption, showed normal growth, development, and germination. However, a cyaA mutant placed under conditions of ionic ( @entity1219 ) or nonionic ( @entity969 ) osmostress exhibited a marked reduction in spore formation and spore germination. When wild-type and cyaA mutant cells at developmental stages were stimulated with 0.2 M @entity1219 or @entity969 , the mutant cells increased @entity1919 accumulation at levels similar to those of the wild-type cells. In contrast, the mutant cells during spore germination had mainly lost the ability to respond to high-ionic osmolarity. In vegetative cells, the cyaA mutant responded normally to osmotic stress. These results suggested that @entity4986 CyaA functions mainly as an ionic osmosensor during spore germination and that CyaA is also required for osmotic tolerance in fruiting formation and sporulation.
