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Li F, Lee M, Esnault C, Wendover K, Guo Y, Atkins P, Zaratiegui M, Levin HL. Identification of an integrase-independent pathway of retrotransposition. SCIENCE ADVANCES 2022; 8:eabm9390. [PMID: 35767609 DOI: 10.1126/sciadv.abm9390] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Retroviruses and long terminal repeat retrotransposons rely on integrase (IN) to insert their complementary DNA (cDNA) into the genome of host cells. Nevertheless, in the absence of IN, retroelements can retain notable levels of insertion activity. We have characterized the IN-independent pathway of Tf1 and found that insertion sites had homology to the primers of reverse transcription, which form single-stranded DNAs at the termini of the cDNA. In the absence of IN activity, a similar bias was observed with HIV-1. Our studies showed that the Tf1 insertions result from single-strand annealing, a noncanonical form of homologous recombination mediated by Rad52. By expanding our analysis of insertions to include repeat sequences, we found most formed tandem elements by inserting at preexisting copies of a related transposable element. Unexpectedly, we found that wild-type Tf1 uses the IN-independent pathway as an alternative mode of insertion.
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Affiliation(s)
- Feng Li
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michael Lee
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Caroline Esnault
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Katie Wendover
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yabin Guo
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul Atkins
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mikel Zaratiegui
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Nelson Biological Laboratories A133, 604 Allison Rd., Piscataway, NJ 08854, USA
| | - Henry L Levin
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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