Efficient translation of poly(A)-deficient mRNAs in Saccharomyces cerevisiae

Abstract

The polyadenylate tail of eukaryotic mRNAs is thought to influence various metabolic phenomena including mRNA stability, translation initiation, and nucleo-cytoplasmic transport. We have analyzed the fate of mRNAs following inactivation of poly(A) polymerase in Saccharomyces cerevisiae containing a temperature-sensitive, lethal mutation (pap1-1) in the gene for poly(A) polymerase (PAP1). Inactivation of poly(A) polymerase (Pap1) by shifting cells to the nonpermissive temperature resulted in the loss of at least 80% of measurable poly(A) within 60 min. Northern blot analysis revealed the disappearance of some mRNAs (CYH2 and HIS4) consistent with a role for poly(A) tails in mRNA stability. However, other mRNAs (TCM1, PAB1, ACT1, and HTB2) accumulate as poly(A)-deficient (A