Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published September 1, 1983 | Published
Journal Article Open

Sequence coding for the alphavirus nonstructural proteins is interrupted by an opal termination codon


We have obtained the nucleotide sequence of the genomic RNAs of two alphaviruses, Sindbis virus and Middelburg virus, over an extensive region encoding the nonstructural (replicase) proteins. In both viruses in an equivalent position an opal (UGA) termination codon punctuates a long otherwise open reading frame. The nonstructural proteins are translated as polyprotein precursors that are processed by posttranslational cleavage into four polypeptide chains; the sequence data presented here indicate that the COOH-terminal polypeptide, ns72, may be produced by read-through of this opal codon. The high degree of amino acid homology between the ns72 polypeptides of the two viruses, in contrast to the lack of conserved sequence upstream from the read-through site, suggests that ns72 plays an important role in viral replication, possibly modulating the action of other replicase components.

Additional Information

© 1983 National Academy of Sciences. Communicated by Ray D. Owen, May 31, 1983. The computer programs used in this work, including production of figures, were written by Tim Hunkapiller and we are grateful to him for access to these programs and instructions in their use. The computer work was performed on the computer facility of Lee Hood and we are grateful for the time on these facilities. Edith Lenches gave expert technical assistance in the maintenance and preparation of virus stocks and cell lines. This work was supported by Grants AI 10793 and GM 06965 from the National Institutes of Health and by Grant PCM 8022830 from the National Science Foundation. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

Attached Files

Published - PNAS-1983-Strauss-5271-5.pdf

Published - STRApnas83.pdf


Files (2.3 MB)
Name Size Download all
1.2 MB Preview Download
1.2 MB Preview Download

Additional details

August 19, 2023
October 17, 2023