REQUIREMENT OF POLY(RC) BINDING-PROTEIN-2 FOR TRANSLATION OF POLIOVIRUS RNA

Poly(rC) binding protein 2 (PCBP2) is one of several cellular proteins that interact specifically with a major stem-loop domain in the polio virus internal ribosome entry site. HeLa cell extracts subjected to st em-loop IV RNA affinity chromatography were depleted of all detectable PCBP2. Such extracts were unable to efficiently translate poliovirus RNA, although extracts recovered from control columns of matrix unlink ed to RNA retained full translation activity. Both translation and pro duction of infectious progeny virus were restored in the PCBP2-deplete d extracts by addition of recombinant PCBP2, but not by PCBP1, which i s a closely related member of the protein family. The data show that P CBP2 is an essential factor, which is required for efficient translati on of poliovirus RNA in HeLa cells.