FIG. 1.

Disruption of translation initiation factor function leads to a decrease in the half-lives of mRNAs. (A) mRNA half-life measurements from strains containing mutations in translation initiation factors from the eIF-4F complex. (B) mRNA half-life measurements from strains containing a mutation in PRT1, a translation initiation factor from the eIF-3 complex. (C) mRNA half-life measurements from a strain containing mutations in both eIF-4E and PRT1. (D) mRNA half-life measurements from strains containing mutations in both PRT1 and UPF1. Steady-state half-life measurements of the PGK1pG mRNA were determined from agarose Northern gels. The numbers above the lanes indicate minutes after transcriptional repression. A representative gel for each strain is shown, and the average value (minutes) of the half-life for the full-length transcript from at least three experiments in each strain is given on the right. The experimental variation for the half-life measurements of each strain was less than ±15%. Northern gels were probed with oligonucleotide oRP141 (5′-AATTGATCTATCGAGGAATTCC-3′), which is complementary to the poly(G) and flanking 3′ sequence in the PGK1pG mRNA. ts, temperature sensitive.