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Updated: Jul 19, 2026

An In Vitro Single-Molecule Imaging Assay for the Analysis of Cap-Dependent Translation Kinetics
Published on: September 15, 2020
Zuotin, a DnaJ molecular chaperone, stimulates cap-independent translation in yeast
Santanu Raychaudhuri1, Vanessa Fontanes, Rajeev Banerjee
1Department of Microbiology, Immunology and Molecular Genetics, UCLA School of Medicine, University of California Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095-1747, USA.
Abstract:
A small inhibitor RNA (IRNA) isolated from yeast has previously been shown to efficiently block poliovirus and hepatitis C virus IRES-mediated translation by sequestering mammalian RNA-binding (transacting) factors that play important roles in cap-independent translation. Here we have investigated the IRNA-binding proteins that might be involved in cap-independent translation in the yeast Saccharomyces cerevisiae. We have identified Zuotin, a DnaJ chaperone protein similar to mammalian HSP-40 chaperone, which interacts strongly with IRNA. Using ZUO1-deleted S. cerevisiae, we demonstrate a preferential requirement of Zuo1p for cap-independent translation mediated by the 5' untranslated region of the yeast TFIID mRNA. Further studies using zuo1delta S. cerevisiae complemented with various Zuo1p mutants indicate that the DnaJ domain of Zuo1p, known to influence its interaction with HSP-70, significantly affects cap-independent translation. These results demonstrate for the first time a role for an established chaperone protein in cap-independent translation of a cellular mRNA.
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