Xuhua Tang1, Yiping Zhu2.3, Stacey L. Baker4, Matthew W. Bowler5,6, Benjamin Jieming Chen1, Chen Chen1, J. Robert Hogg4,#, Stephen P. Goff2,3,# and Haiwei Song1,7,8,#
1 Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
2 Department of Biochemistry and Molecular Biophysics, Columbia University, HHSC 1310C, 701 W. 168th St., New York, NY 10032, USA
3 Howard Hughes Medical Institute, Columbia University, HHSC 1310C, 701 W. 168th St., New York, NY 10032, USA
4 Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, 50 South Drive, Bethesda, MD 20892, USA
5 European Molecular Biology Laboratory, Grenoble Outstation, 71 avenue des Martyrs,
CS 90181 F-38042 Grenoble, France
6 Unit of Virus Host-Cell Interactions, Univ. Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, CS 90181 F-38042 Grenoble, France
7 Life Sciences Institute, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China
8 Department of Biochemistry, National University of Singapore, 14 Science Drive, Singapore 117543, Singapore
#Correspondence should be addressed to S.P.G. (firstname.lastname@example.org) or J.R.H. (email@example.com) or H.S. (firstname.lastname@example.org)
Published in Nature Communications on 22 June 2016.
Retroviral reverse transcriptase (RT) of Moloney Murine Leukemia Virus (MoMLV) is expressed in the form of a large Gag-Pol precursor protein by suppression of translational termination in which the maximal efficiency of stop codon readthrough depends on the interaction between MoMLV RT and peptidyl release factor 1 (eRF1). Here we report the crystal structure of MoMLV RT in complex with eRF1. The MoMLV RT interacts with the C-terminal domain of eRF1 via its RNase H domain to sterically occlude the binding of peptidyl release factor 3 (eRF3) to eRF1. Promotion of readthrough by MoMLV RNase H prevents nonsense-mediated mRNA decay (NMD) of mRNAs. Comparison of our structure with that of HIV RT explains why HIV RT cannot interact with eRF1. Our results provide a mechanistic view of how MoMLV manipulates the host translation termination machinery for synthesis of its own proteins.
Figure. 1. Overall structure of MoMLV-RT complex with mouse eRF1. Domains N, M, and C of eRF1 are colored in pink, lightblue and green, respectively. MoMLV RT polymerase domain is colored in grey and RNase H domain in yellow.
Figure. 2. Model for the mechanism of RT RNase H domain to promote readthough in cis. The cartoon shows termination suppression activity may be strongest in cis, due to the newly synthesized MoMLV-RT RNase H polypeptide reaching back at the upstream termination codon on the same mRNA to interact with eRF1 and enhance readthrough.
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