RNA helicase A (RHA) is a highly conserved DEAD-box protein that activates transcription, modulates RNA splicing and binds the nuclear pore complex. The life cycle of typical mRNA involves RNA processing and translation after ribosome scanning of a relatively unstructured 5′ untranslated region (UTR). The precursor RNAs of retroviruses and selected cellular genes harbor a complex 5′ UTR and use a yet-to-be-identified host post-transcriptional effector to stimulate efficient translation. Here we show that RHA recognizes a structured 5′-terminal post-transcriptional control element (PCE) of a retrovirus and the JUND growth-control gene. RHA interacts with PCE RNA in the nucleus and cytoplasm, facilitates polyribosome association and is necessary for its efficient translation. Our results reveal a previously unidentified role for RHA in translation and implicate RHA as an integrative effector in the continuum of gene expression from transcription to translation.
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We are grateful to K. Green-Church and the Ohio State University CCIC proteomics core for mass spectrophotometry, W.C. Merrick for valuable discussion, K. Hayes, I. Younis and members of the K.B.-L. laboratory for comments on the manuscript and T. Vojt for figure preparation. This work was supported by grants from the US National Institutes of Health (P01CA16058 and P30CA100730).