The Neurospora crassa colonial temperature-sensitive 3 (cot-3) gene encodes protein elongation factor 2.
At elevated temperatures, the Neurospora crassa mutant colonial, temperature-sensitive 3 (cot-3) forms compact, highly branched colonies. Growth of the cot-3 strain under these conditions also results in the loss of the lower molecular weight (LMW) isoform of the Ser/Thr protein kinase encoded by the unlinked cot-1 gene, whose function is also involved in hyphal elongation. The unique cot-3 gene has been cloned by complementation and shown to encode translation elongation factor 2 (EF-2). As expected for a gene with a general role in protein synthesis, cot-3 mRNA is abundantly expressed throughout all asexual phases of the N. crassa life cycle. The molecular basis of the cot-3 mutation was determined to be an ATT to AAT transversion, which causes an Ile to Asn substitution at residue 278. Treatment with fusidic acid (a specific inhibitor of EF-2) inhibits hyphal elongation and induces hyperbranching in a manner which mimics the cot-3 phenotype, and also leads to a decrease in the abundance of the LMW isoform of COT1. This supports our conclusion that the mutation in cot-3 which results in abnormal hyphal elongation/branching impairs EF-2 function and confirms that the abundance of a LMW isoform of COT1 kinase is dependent on the function of this general translation factor.
Propheta
O
O
Department of Plant Pathology and Microbiology, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel.
Vierula
J
J
Toporowski
P
P
Gorovits
R
R
Yarden
O
O
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D017124:Conserved Sequence; D003470:Culture Media; D005672:Fusidic Acid / Q000494:pharmacology; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D020652:Peptide Elongation Factor 2 / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012568:Schizosaccharomyces / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D003470:Culture Media; D020652:Peptide Elongation Factor 2; D020033:Protein Isoforms; D005672:Fusidic Acid