Growth factor regulated expression of poly(A)+ binding protein messenger RNA

A 72,000 mol wt protein designated PABP binds to the poly(A)+ track of messenger RNAs with high affinity and has been suggested to play an important role in mRNA metabolism in eucaryotic cells. We have employed a human PABP cDNA probe to study the expression of this gene at the mRNA level in BALB/c3T3 mouse cells under different growth conditions and in exponentially growing HeLa cells throughout the cell division cycle. We describe experiments which establish that in BALB/c3T3 cells the expression of this gene is growth factor regulated. Moreover, the gene behaves like a primary response gene in that its induction in quiescent cells does not require the prior synthesis of other growth factor-regulated proteins. In exponentially growing HeLa cells PABP mRNA is expressed throughout the cell division cycle indicating that the expression of this gene is not limited to a specific phase of the cell cycle.