The RNase H activity of retroviral reverse transcriptases (RTs) degrades viral genomic RNA after it has been copied into DNA, removes the tRNA used to initiate negative-strand DNA synthesis, and generates and removes the polypurine tract (PPT) primer used to initiate positive-strand DNA synthesis. The cleavages that remove the tRNA and that generate and remove the PPT primer must be specific to generate linear viral DNAs with ends that are appropriate for integration into the host cell genome. The crystal structure of human immunodeficiency virus type 1 (HIV-1) RT in a complex with an RNA/DNA duplex derived from the PPT revealed that the 5' end of the PPT deviates from traditional Watson-Crick base pairing. This unusual structure may play a role in the proper recognition of the PPT by HIV-1 RT. We made substitution mutations in the 5' end of the PPT and determined their effects on virus titer. The results indicated that single and double mutations in the 5' end of the PPT had modest effects on virus replication in a single-cycle assay. More complex mutations had stronger effects on virus titer. Analysis of the two-long-terminal-repeat circle junctions derived from infecting cells with the mutant viruses indicated that the mutations affected RNase H activity, resulting in the retention of PPT sequences on viral DNA. The mutants tested preferentially retained specific segments of the PPT, suggesting an effect on cleavage specificity. These results suggest that structural features of the PPT are important for its recognition and cleavage in vivo.
This research output has an Altmetric Attention Score of 9. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 28 July 2026.
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#5,074,702
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Outputs from Journal of Virology
#5,723
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#11,279
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Outputs of similar age from Journal of Virology
#57
of 216 outputs
Altmetric has tracked 34,115,020 research outputs across all sources so far. Compared to these this one has done well and is in the 83rd percentile: it's in the top 25% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 30,493 research outputs from this source. They typically receive more attention than average, with a mean Attention Score of 8.9. This one has gotten more attention than average, scoring higher than 71% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 81,754 tracked outputs that were published within six weeks on either side of this one in any source. This one has done well, scoring higher than 79% of its contemporaries.
We're also able to compare this research output to 216 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 58% of its contemporaries.
