# Spider Eye Development Editing and Silk Fiber Engineering Using CRISPR‐Cas

## TL;DR

Researchers used CRISPR to edit spider genes, causing eye loss and creating red fluorescent silk, opening new possibilities in genetics and material science.

## Contribution

First successful CRISPR-based gene editing in spiders, enabling knock-outs and knock-ins for functional studies and silk modification.

## Key findings

- Knock-out of the sine oculis gene caused complete eye loss in spider offspring.
- Knock-in of a red fluorescent protein into a silk gene produced red fluorescent silk fibers.
- CRISPR editing did not disrupt the assembly of spider silk proteins.

## Abstract

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.

Spiders exhibit unique traits with significant implications for a diversity of fields, and gene editing provides new opportunities for advancing research in these areas. In this study, we developed a CRISPR‐Cas9 protocol for spiders, enabling gene knock‐outs/knock‐ins to study gene function and introduce new phenotypic traits.