Figure 5.

Smg1 is not required for Smg6 activity and Smg5 is required for exonucleolytic NMD activity. (A) Gadd45 3′ expression relative to 5′ expression in indicated genotypes, measured by qRT-PCR. The 3′ region is preferentially stabilized in pcm¹⁴ mutants with or without functional Smg1. Error bars represent 2 SEM. P-value listed for each condition compared to pcm⁺ or between indicated conditions determined by two-sided Student’s t-test. n ≥ 3 for all conditions. Data for pcm⁺ and pcm¹⁴ conditions are duplicated from Figure 2E and displayed here for comparison between relevant genotypes. (B) Relative expression of the endogenous NMD target Gadd45 measured by qRT-PCR using the 5′ primer pair in Smg6^292/Df mutants compared to Smg6⁺ controls in either Smg1⁺ or Smg1^32AP mutant backgrounds. Error bars represent 2 SEM. P-value between conditions determined by two-sided Student’s t-test. n ≥ 3 for all conditions. (C) Adult viability of Smg1^32AP and Smg6^292/Df null mutants, and Smg1^32AP; Smg6^292/Df double mutants. Error bars represent 95% confidence interval of the binomial distribution. P-value listed between indicated conditions determined by the test of equal or given proportions. n displays total number of animals scored. Data for Smg1^32AP are duplicated from Figure 4A and displayed here for comparison between relevant genotypes. Primers for all qPCR experiments were located 5′ to the Gadd45 termination sequence.