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Updated: Aug 8, 2026
Amplification, Next-generation Sequencing, and Genomic DNA Mapping of Retroviral Integration Sites
Published on: March 22, 2016
Division of labor within human immunodeficiency virus integrase complexes: determinants of catalysis and target DNA
Tracy L Diamond1, Frederic D Bushman
1University of Pennsylvania School of Medicine, Department of Microbiology, 3610 Hamilton Walk, Philadelphia, PA 19104-6076, USA.
Insights
Human immunodeficiency virus integrase (IN) monomers have dual roles in DNA binding and catalysis. A single IN monomer performs both target DNA capture and integration, guiding inhibitor design.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- Human immunodeficiency virus integrase (IN) is essential for viral replication, mediating the integration of viral cDNA into host cell DNA.
- IN functions as a multimer, but the specific roles of individual monomers in DNA binding and catalysis remain largely uncharacterized.
Purpose of the Study:
- To elucidate the functional distribution of target DNA capture and catalysis within the IN multimer.
- To determine if distinct monomers are responsible for DNA binding versus catalytic activity.
Main Methods:
- Utilized in vitro forced complementation assays with pairs of IN deletion derivatives to probe cis-trans relationships.
- Analyzed effects of amino acid substitutions on catalysis and target site selection within complementing complexes.
- Employed assay mixtures with three different IN genotypes to assess monomeric function.
Main Results:
- Demonstrated that the IN variant contributing the active catalytic domain is also responsible for recognizing target DNA.
- Established that a single IN monomer performs both target DNA capture and catalytic functions.
- Identified specific ligands bound by the catalytically relevant IN monomer.
Conclusions:
- A single IN monomer possesses dual functionality for both target DNA recognition and catalysis.
- These findings provide critical insights into the mechanism of HIV integration.
- The data can inform the development of more specific inhibitors targeting the IN active site.
Abstract:
Following the completion of reverse transcription, the human immunodeficiency virus integrase (IN) enzyme covalently links the viral cDNA to a host cell chromosome. An IN multimer carries out this reaction, but the roles of individual monomers within the complex are mostly unknown. Here we analyzed the distribution of functions for target DNA capture and catalysis within the IN multimer. We used forced complementation between pairs of IN deletion derivatives in vitro as a tool for probing cis-trans relationships and analyzed amino acid substitutions affecting either catalysis or target site selection within these complementing complexes. This allowed the demonstration that the IN variant contributing the active catalytic domain was also responsible for recognition of the integration target DNA. We were further able to establish that a single monomer is responsible for both functions by use of assay mixtures containing three different IN genotypes. These data specify the ligands bound at the catalytically relevant IN monomer and allow more-specific modeling of the mechanism of inhibitors that also bind this surface of IN.
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