FIG. 4.

PABP contributes to the stabilization of polyadenylated mRNA. (A) Western analysis detecting PABP in K562 S130 extract (lane 1) and poly(A)-depleted S130 extract (lane 2), using the PABP-specific monoclonal antibody 10E10. Positions of migration of PABP and molecular weight markers are shown. (B) A 2-h in vitro mRNA decay reaction using 5′-end-labeled α^wtA⁺ was carried out with poly(A)-depleted K562 S130 extract. Complete S130 extract was used in lane 3; poly(A)-depleted extract was used in lanes 4 through 11. The amount of recombinant PABP or RBD added is indicated. “α^wtA⁻” denotes migration of the unadenylated α^wt RNA. Resolution of the RNA and molecular size markers (indicated in nucleotides) are as described in the legend to Fig. 1.