Table 1.

Summary of experiments using differentGCN2c alleles on URA3 CEN vectors to test the effects of initiation defects on ribosomal frameshiftinga

PlasmidGCN2cmutationRelative growthbMean % PRFc ± SD (fold WT level)% −1 frameshift suppressiond
−1+1
p722None (WT)++++3.4 ± 0.7 (1)5.9 ± 0.7 (1)0.044
p1056E532K, E1522K+++6.3 ± 0.6 (1.8)5.8 ± 0.6 (1)0.043
p1052M719V, E1537G++6.4 ± 0.3 (1.8)6.2 ± 0.5 (1)0.044
p1054E532K, E1537G+6.4 ± 0.2 (1.8)5.9 ± 0.6 (1)0.046
  • a All strains had strong killer phenotypes and stably maintained L-A and M1.

  • b Corresponds to initiation competence.

  • c As measured with pTI25 (0 frame control) or with pF8 or pJD104 (−1 or +1 ribosomal frameshift tester, respectively) (2, 14).

  • d Suppression of a nonspecific frameshift mutation (pTI24/pTI25 × 100), in all cases approximately equal to the WT value.