The snpA , a temperature‐sensitive suppressor of npgA1 , encodes the eukaryotic translation release factor, eRF1, in Aspergillus nidulans

The npgA1 mutation causes defects in the outer layer of the cell wall resulting in a colorless colony. In this study, a temperature‐sensitive suppressor of npgA1 named snpA was isolated by UV mutagenesis. The suppressing mutant showed pleiotropic phenotypes in cellular structure and developmental processes when incubated at a temperature of 37 °C or above. At 37 °C, multiple germ tubes emerged from germinating conidia. Moreover, at 42 °C conidia germination was delayed more than 12 h and hyphal growth was strongly inhibited. The suppressor allele, snpA6 , is recessive and maps to the linkage group III. A gene complementing the mutation was identified employing the chromosome III‐specific cosmid library. Sequencing analysis revealed that the snpA gene encodes the eukaryotic polypeptide release factor, eRF1. The snpA6 allele contains a G–A mutation resulting in SnpA E117K , which may allow read‐through of the nonsense mutation in the npgA1 allele in a similar manner to the yeast omni‐potent suppressor SUP45 and SUP35 .