Publications by authors named "Alena L Bishop"

3 Publications

  • Page 1 of 1

Optimized CRISPR tools and site-directed transgenesis towards gene drive development in Culex quinquefasciatus mosquitoes.

Nat Commun 2021 05 20;12(1):2960. Epub 2021 May 20.

Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA.

Culex mosquitoes are a global vector for multiple human and animal diseases, including West Nile virus, lymphatic filariasis, and avian malaria, posing a constant threat to public health, livestock, companion animals, and endangered birds. While rising insecticide resistance has threatened the control of Culex mosquitoes, advances in CRISPR genome-editing tools have fostered the development of alternative genetic strategies such as gene drive systems to fight disease vectors. However, though gene-drive technology has quickly progressed in other mosquitoes, advances have been lacking in Culex. Here, we develop a Culex-specific Cas9/gRNA expression toolkit and use site-directed homology-based transgenesis to generate and validate a Culex quinquefasciatus Cas9-expressing line. We show that gRNA scaffold variants improve transgenesis efficiency in both Culex quinquefasciatus and Drosophila melanogaster and boost gene-drive performance in the fruit fly. These findings support future technology development to control Culex mosquitoes and provide valuable insight for improving these tools in other species.
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http://dx.doi.org/10.1038/s41467-021-23239-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8137705PMC
May 2021

Small-Molecule Control of Super-Mendelian Inheritance in Gene Drives.

Cell Rep 2020 06;31(13):107841

Chemical Biology and Therapeutics Science, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; Divisions of Renal Medicine and Engineering, Brigham and Women's Hospital, Boston, MA 02115, USA. Electronic address:

Synthetic CRISPR-based gene-drive systems have tremendous potential in public health and agriculture, such as for fighting vector-borne diseases or suppressing crop pest populations. These elements can rapidly spread in a population by breaching the inheritance limit of 50% dictated by Mendel's law of gene segregation, making them a promising tool for population engineering. However, current technologies lack control over their propagation capacity, and there are important concerns about potential unchecked spreading. Here, we describe a gene-drive system in Drosophila that generates an analog inheritance output that can be tightly and conditionally controlled to between 50% and 100%. This technology uses a modified SpCas9 that responds to a synthetic, orally available small molecule, fine-tuning the inheritance probability. This system opens a new avenue to feasibility studies for spatial and temporal control of gene drives using small molecules.
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http://dx.doi.org/10.1016/j.celrep.2020.107841DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7587219PMC
June 2020

A transcomplementing gene drive provides a flexible platform for laboratory investigation and potential field deployment.

Nat Commun 2020 01 17;11(1):352. Epub 2020 Jan 17.

Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, 92093, USA.

CRISPR-based gene drives can spread through wild populations by biasing their own transmission above the 50% value predicted by Mendelian inheritance. These technologies offer population-engineering solutions for combating vector-borne diseases, managing crop pests, and supporting ecosystem conservation efforts. Current technologies raise safety concerns for unintended gene propagation. Herein, we address such concerns by splitting the drive components, Cas9 and gRNAs, into separate alleles to form a trans-complementing split-gene-drive (tGD) and demonstrate its ability to promote super-Mendelian inheritance of the separate transgenes. This dual-component configuration allows for combinatorial transgene optimization and increases safety by restricting escape concerns to experimentation windows. We employ the tGD and a small-molecule-controlled version to investigate the biology of component inheritance and resistant allele formation, and to study the effects of maternal inheritance and impaired homology on efficiency. Lastly, mathematical modeling of tGD spread within populations reveals potential advantages for improving current gene-drive technologies for field population modification.
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http://dx.doi.org/10.1038/s41467-019-13977-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6969112PMC
January 2020
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