Neurospora crassa temperature-sensitive mutant apparently defective in protein synthesis

A temperature-sensitive mutant of Neurospora was isolated which appeared to be defective in the initiation of protein synthesis. The defect in mutant 34Cts was apparently due to a single gene mutation, and was recessive in heterokaryons. Conidial germination was normal and hyphal growth was nearly so in the mutant at 20 C, but both were greatly inhibited at 35 C. After 15 min at 35 C there was a reduced rate of protein synthesis, followed by decreases in ribonucleic acid and deoxyribonucleic acid synthesis. The percentage of ribosomes in polysomes declined at 35 C and the average size of polysomes decreased. Because the decrease in protein synthesis, it was believed that some part of the translational system may be affected by the mutation. Mutant 34Cts was given the designation psi-1.