Spider Eye Development Editing and Silk Fiber Engineering Using CRISPR-Cas.

CRISPR-Cas9 gene editing represents an effective and precise technology to induce mutations in the genome, and it has been applied to a wide range of organisms for diverse purposes. However, CRISPR-based gene editing in spiders has not been reported to date. In this study, we demonstrate CRISPR-mediated microinjection in parental spiders leading to both knock-out (KO) and knock-in (KI) mutations within the spider's offspring. The KO of the gene sine oculis causes total eye loss, confirming the role of the gene in the development of all spider eyes. The KI of a monomeric red fluorescent protein (mRFP-KI) within a spider silk gene encoding one compound of the major ampullate silk of the spider Parasteatoda tepidariorum yields red fluorescent silk fibers. This finding demonstrates the feasibility of functionalizing silk proteins in spiders using CRISPR-based gene editing without influencing silk assembly. Our study expands the application of CRISPR to spiders and provides insights in the fields of developmental genetics as well as material sciences.