Gene expression can be controlled by changing the half-lifes of specific mRNAs in response
to intracellular events or to extracellular stimuli. Many experiments suggest that mRNA
turnover in mammalian cells is linked to poly (A) metabolism, which might be affected by the
efficiency of the cytoplasmic poly (A) binding protein in protecting poly (A) from nucleolytic
attack. Most newly synthesized mRNAs are modified post-transcriptionally by the addition of
a poly (A) tract at their 3'termini. Although the detailed mechanisms of poly (A) synthesis are …