FIG. 5.

The rates of both deadenylation and decapping are increased when translation initiation is impaired. Transcriptional pulse-chase analysis of the PGK1pG mRNA in various translation initiation mutant strains is used to examine deadenylation and fragment production. Time points used after a 6-min transcriptional induction and subsequent repression are shown above each lane. The top fragment was produced by cleavage of the full-length mRNA with RNase H and oligonucleotide oRP70. This cleavage shortens the mRNA enough to visualize small differences at the 3′ end. The bottom fragment is the decay intermediate stabilized by the poly(G) insertion in the 3′ UTR. The blots were probed with oRP141. ts, temperature sensitive.