Conditional expression of Cas9 and dCas9 in Lucilia cuprina reveals dCas9-associated lethality
Conditional expression of Cas9 and dCas9 in Lucilia cuprina reveals dCas9-associated lethality
Tags: CRISPRAlexis Kriete, Tatiana Basika, Rossina Novas, et al., bioRxiv, 2025.
Conditional sex transformation systems are promising tools in the fight against insect pests. In this study, we developed and tested CRISPR-based, tetracycline-repressible sex transformation strains in the Australian sheep blowfly, Lucilia cuprina. Two CRISPR effector molecules, Cas9 and dCas9, were employed to target the sex-determining gene transformer with the goal of turning female blowflies into males. The Cas9 version of the system induced robust knockout of a visual marker gene but failed to trigger sex transformation without external provision of transformer-targeting sgRNAs. Furthermore, we found that dCas9 expression was linked to several deleterious phenotypes, including developmental delays, reduced body weight, and death. Our study provides the first proof-of-concept conditional CRISPR systems in L. cuprina, and suggests that while dCas9 is toxic at high levels in this species, Cas9 is well-tolerated and may be able to induce sex transformation with minor modifications to the system.
