Prokaryotic ribosomes recode the HIV-1 gag-pol-1 frameshift sequence by an E/P site post-translocation simultaneous slippage mechanism

The mechanism favoured for −1 frameshifting at typical retrovlral sites is a pre-translocatlon simultaneous slippage model. An alternative post-translocation mechanism would also generate the same protein sequence across the frameshift site and therefore In this study the strategic placement of a st...

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Bibliographic Details
Published in:Nucleic acids research 1995-05, Vol.23 (9), p.1487-1494
Main Authors: Horsfield, Julie A., Wilson, Daniel N., Mannering, Sally A., Adamski, Frances M., Tate, Warren P.
Format: Article
Language:English
Subjects:
AIDS/HIV
Base Sequence
Codon - genetics
Escherichia coli - genetics
Frameshift Mutation
HIV-1 - genetics
HIV-1 - metabolism
Human immunodeficiency virus 1
Molecular Sequence Data
Protein Biosynthesis
Ribosomes - genetics
Ribosomes - metabolism
RNA, Messenger - genetics
RNA, Messenger - metabolism
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Summary:The mechanism favoured for −1 frameshifting at typical retrovlral sites is a pre-translocatlon simultaneous slippage model. An alternative post-translocation mechanism would also generate the same protein sequence across the frameshift site and therefore In this study the strategic placement of a stop codon has been used to distinguish between the two mechanisms. A 26 base pair frameshift sequence from the HIV-1 gag-pol overlap has been modified to include a stop codon immediately 3′ to the heptanucleotlde frameshift signal, where it often occurs naturally in retrovlral recodlng sites. Stop codons at the 3′-end of the heptanucleotide sequence decreased the frame-shifting efficiency on prokaryote ribosomes and the recodlng event was further depressed when the levels of the release factors In vivo were increased. In the presence of elevated levels of a defective release factor 2, frameshifting efficiency In vivo was increased in the constructs containing the stop codons recognized specifically by that release factor. These results are consistent with the last six nucleotldes of the heptanucleotide slippery sequence occupying the rlbosomal E and P sites, rather than the P and A sites, with the next codon occupying the A site and therefore with a post-translocation rather than a pre-transloca-tion −1 slippage model.
ISSN:0305-1048
1362-4962
DOI:10.1093/nar/23.9.1487