Cyclic AMP-dependent, constitutive thermotolerance in the adenylate cyclase-deficient cr-1 (crisp) mutant of Neurospora crassa.
We investigated the heat shock response of the adenylate cyclase deficient mutant cr-1 (crisp) of Neurospora crassa. This strain was observed to be much more resistant to a lethal temperature of 50 degrees C than the wild type. This constitutive thermotolerance was absent in cr-1 conidiospores raised on cyclic AMP (cAMP, 2.5 mM) supplemented solid medium, but was partially restored when the conidiospores were germinated at 30 degrees C, a temperature which fails to induce thermotolerance in the wild-type strain. Two other crisp-like Neurospora mutants, cr-2 and cr-3 which, in contrast to cr-1, contain normal levels of cAMP, did not exhibit the thermotolerance phenomenon observed for cr-1. A cr-1, pe, fl (crisp-microconidial) strain also lacked the ability to tolerate a lethal heat treatment. Our results demonstrate that the adenylate cyclase deficient cr-1 mutant of Neurospora crassa expresses a constitutive thermotolerant phenotype as a consequence of its primary genetic defect: low levels of cAMP.
Cruz
A K
AK
Departmento de Biologia, Faculdade de Filosofia, Ciências e Letras, Ribeirão Preto Universidade de São Paulo, Brasil.
Terenzi
H F
HF
Jorge
J A
JA
Terenzi
H F
HF
D000262:Adenylyl Cyclases / Q000235:genetics*; D002872:Chromosome Deletion; D000242:Cyclic AMP / Q000494:pharmacology*; D005796:Genes; D005800:Genes, Fungal; D007700:Kinetics; D009154:Mutation; D009491:Neurospora / Q000235:genetics*; D009492:Neurospora crassa / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D013696:Temperature
D000242:Cyclic AMP; D000262:Adenylyl Cyclases