Foamy virus reverse transcriptase is expressed independently from the Gag protein. NLM AIDSLINE Important note: Information in this article was accurate in 1996. The state of the art may have changed since the publication date.

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Foamy virus reverse transcriptase is expressed independently from the Gag protein.

Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):4137-41. Unique Identifier : AIDSLINE MED/96210606
Enssle J; Jordan I; Mauer B; Rethwilm A; Institut fur Virologie und Immunbiologie, Wurzburg, Germany.

Abstract: In the foamy virus (FV) subgroup of retroviruses the pol genes are located in the +1 reading frame relative to the gag genes and possess potential ATG initiation codons in their 5' regions. This genome organization suggests either a + 1 ribosomal frameshift to generate a Gag-Pol fusion protein, similar to all other retroviruses studied so far, or new initiation of Pol translation, as used by pararetroviruses, to express the Pol protein. By using a genetic approach we have ruled out the former possibility and provide evidence for the latter. Two down-mutations (M53 and M54) of the pol ATG codon were found to abolish replication and Pol protein expression of the human FV isolate. The introduction of a new ATG in mutation M55, 3' to the down-mutated ATG of mutation M53, restored replication competence, indicating that the pol ATG functions as a translational initiation codon. Two nonsense mutants (M56 and M57), which functionally separated gag and pol with respect to potential frame-shifting sites, were also replication-competent, providing further genetic evidence that FVs express the Pol protein independently from Gag. Our results show that during a particular step of the replication cycle, FVs differ fundamentally from all other retroviruses.
Keywords: Amino Acid Sequence Animal Base Sequence Cell Line Frameshift Mutation Gene Products, gag/*BIOSYNTHESIS Gene Products, pol/BIOSYNTHESIS Genes, gag Genes, pol Genome, Viral Hamsters Human Kidney Molecular Sequence Data Mutagenesis, Site-Directed Peptide Chain Initiation Recombinant Fusion Proteins/BIOSYNTHESIS Ribosomes/METABOLISM RNA-Directed DNA Polymerase/*BIOSYNTHESIS Spumavirus/GENETICS/ISOLATION & PURIF/*PHYSIOLOGY Support, Non-U.S. Gov't Translation, Genetic Virus Replication JOURNAL ARTICLEKWDaminoacidsequenceanimalbasesequencecelllineframeshiftmutationgeneproducts,gag/
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Copyright © 1996 - National Library of Medicine. Reproduced under license with the National Library of Medicine, Bethesda, MD.

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