Division of Labor by the HELQ, BLM, and FANCM Helicases during Homologous Recombination Repair in <i>Drosophila melanogaster</i>
Repair of DNA double-strand breaks by homologous recombination (HR) requires a carefully orchestrated sequence of events involving many proteins. One type of HR, synthesis-dependent strand annealing (SDSA), proceeds via the formation of a displacement loop (D-loop) when RAD51-coated single-stranded...
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MDPI AG
2022-03-01
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| Series: | Genes |
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| Online Access: | https://www.mdpi.com/2073-4425/13/3/474 |
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| author | Adam Thomas Julie Cox Kelly B. Wolfe Carrie Hui Mingalone Haleigh R. Yaspan Mitch McVey |
| author_facet | Adam Thomas Julie Cox Kelly B. Wolfe Carrie Hui Mingalone Haleigh R. Yaspan Mitch McVey |
| author_sort | Adam Thomas |
| collection | DOAJ |
| description | Repair of DNA double-strand breaks by homologous recombination (HR) requires a carefully orchestrated sequence of events involving many proteins. One type of HR, synthesis-dependent strand annealing (SDSA), proceeds via the formation of a displacement loop (D-loop) when RAD51-coated single-stranded DNA invades a homologous template. The 3′ end of the single-stranded DNA is extended by DNA synthesis. In SDSA, the D-loop is then disassembled prior to strand annealing. While many helicases can unwind D-loops in vitro, how their action is choreographed in vivo remains to be determined. To clarify the roles of various DNA helicases during SDSA, we used a double-strand gap repair assay to study the outcomes of homologous recombination repair in <i>Drosophila melanogaster</i> lacking the BLM, HELQ, and FANCM helicases. We found that the absence of any of these three helicases impairs gap repair. In addition, flies lacking both BLM and HELQ or HELQ and FANCM had more severe SDSA defects than the corresponding single mutants. In the absence of BLM, a large percentage of repair events were accompanied by flanking deletions. Strikingly, these deletions were mostly abolished in the <i>blm helq</i> and <i>blm fancm</i> double mutants. Our results suggest that the BLM, HELQ, and FANCM helicases play distinct roles during SDSA, with HELQ and FANCM acting early to promote the formation of recombination intermediates that are then processed by BLM to prevent repair by deletion-prone mechanisms. |
| first_indexed | 2024-03-09T19:48:31Z |
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| id | doaj.art-9f01b08ed22b4f059af5d2bbc9597150 |
| institution | Directory Open Access Journal |
| issn | 2073-4425 |
| language | English |
| last_indexed | 2024-03-09T19:48:31Z |
| publishDate | 2022-03-01 |
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| series | Genes |
| spelling | doaj.art-9f01b08ed22b4f059af5d2bbc95971502023-11-24T01:18:48ZengMDPI AGGenes2073-44252022-03-0113347410.3390/genes13030474Division of Labor by the HELQ, BLM, and FANCM Helicases during Homologous Recombination Repair in <i>Drosophila melanogaster</i>Adam Thomas0Julie Cox1Kelly B. Wolfe2Carrie Hui Mingalone3Haleigh R. Yaspan4Mitch McVey5Department of Biology, Tufts University, Medford, MA 02155, USADepartment of Biology, Tufts University, Medford, MA 02155, USADepartment of Biology, Tufts University, Medford, MA 02155, USADepartment of Biology, Tufts University, Medford, MA 02155, USADepartment of Biology, Tufts University, Medford, MA 02155, USADepartment of Biology, Tufts University, Medford, MA 02155, USARepair of DNA double-strand breaks by homologous recombination (HR) requires a carefully orchestrated sequence of events involving many proteins. One type of HR, synthesis-dependent strand annealing (SDSA), proceeds via the formation of a displacement loop (D-loop) when RAD51-coated single-stranded DNA invades a homologous template. The 3′ end of the single-stranded DNA is extended by DNA synthesis. In SDSA, the D-loop is then disassembled prior to strand annealing. While many helicases can unwind D-loops in vitro, how their action is choreographed in vivo remains to be determined. To clarify the roles of various DNA helicases during SDSA, we used a double-strand gap repair assay to study the outcomes of homologous recombination repair in <i>Drosophila melanogaster</i> lacking the BLM, HELQ, and FANCM helicases. We found that the absence of any of these three helicases impairs gap repair. In addition, flies lacking both BLM and HELQ or HELQ and FANCM had more severe SDSA defects than the corresponding single mutants. In the absence of BLM, a large percentage of repair events were accompanied by flanking deletions. Strikingly, these deletions were mostly abolished in the <i>blm helq</i> and <i>blm fancm</i> double mutants. Our results suggest that the BLM, HELQ, and FANCM helicases play distinct roles during SDSA, with HELQ and FANCM acting early to promote the formation of recombination intermediates that are then processed by BLM to prevent repair by deletion-prone mechanisms.https://www.mdpi.com/2073-4425/13/3/474double-strand breakD-loopmutagenesisend joiningtransposon |
| spellingShingle | Adam Thomas Julie Cox Kelly B. Wolfe Carrie Hui Mingalone Haleigh R. Yaspan Mitch McVey Division of Labor by the HELQ, BLM, and FANCM Helicases during Homologous Recombination Repair in <i>Drosophila melanogaster</i> Genes double-strand break D-loop mutagenesis end joining transposon |
| title | Division of Labor by the HELQ, BLM, and FANCM Helicases during Homologous Recombination Repair in <i>Drosophila melanogaster</i> |
| title_full | Division of Labor by the HELQ, BLM, and FANCM Helicases during Homologous Recombination Repair in <i>Drosophila melanogaster</i> |
| title_fullStr | Division of Labor by the HELQ, BLM, and FANCM Helicases during Homologous Recombination Repair in <i>Drosophila melanogaster</i> |
| title_full_unstemmed | Division of Labor by the HELQ, BLM, and FANCM Helicases during Homologous Recombination Repair in <i>Drosophila melanogaster</i> |
| title_short | Division of Labor by the HELQ, BLM, and FANCM Helicases during Homologous Recombination Repair in <i>Drosophila melanogaster</i> |
| title_sort | division of labor by the helq blm and fancm helicases during homologous recombination repair in i drosophila melanogaster i |
| topic | double-strand break D-loop mutagenesis end joining transposon |
| url | https://www.mdpi.com/2073-4425/13/3/474 |
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