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 poliovirus internal ribosome entry site. HeLa cell extracts subjected to stem-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 unlinked to RNA retained full translation activity. Both translation and production of infectious progeny virus were restored in the PCBP2-depleted extracts by addition of recombinant PCBP2, but not by PCBP1, which is a closely related member of the protein family. The data show that PCBP2 is an essential factor, which is required for efficient translation of poliovirus RNA in HeLa cells.