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 degrees C or above. At 37 degrees C, multiple germ tubes emerged from germinating conidia. Moreover, at 42 degrees C conidia germination was delayed more than 12h 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.
Han
Kap-Hoon
KH
Research Center for Biomedicinal Resources, Pai Chai University, Daejeon 302-735, Republic of Korea.
Kim
Jee Hyun
JH
Kim
Won-Sin
WS
Han
Dong-Min
DM
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001233:Aspergillus nidulans / Q000166:cytology / Q000235:genetics*; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics*; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D025301:Hyphae / Q000235:genetics; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D016366:Open Reading Frames; D010454:Peptide Termination Factors / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000235:genetics; D013489:Suppression, Genetic; D013696:Temperature; D014466:Ultraviolet Rays
D004271:DNA, Fungal; D005656:Fungal Proteins; D010454:Peptide Termination Factors