An additional copy of the adenylate cyclase-encoding gene relieves developmental defects produced by a mutation in a vegetative incompatibility-controlling gene in Podospora anserina.

To identify cellular functions involved in vegetative incompatibility in filamentous fungi, we have initiated the cloning of Podospora anserina (Pa) mod genes. These genes interfere with the lethal reaction triggered by interaction between incompatible het genes. A gene (Pa AC) has been cloned by complementation of developmental defects caused by a mutation in the mod-D gene. This gene encodes a protein of 2145 amino acids (aa)that exhibits strong similarities with many adenylate cyclases (AC). About 65% aa identity has been found between the sequence of the polypeptide encoded by this Pa AC gene and the AC of Neurospora crassa. The organization of peptidic domains in the polypeptide encoded by Pa AC is closely related to that of Saccharomyces cerevisiae CYR1. Restriction-fragment-length polymorphism (RFLP) and genetic analysis have shown that Pa AC and mod-D are distinct genes.