# CRISPR/Cas9-Mediated Disruption of lrp6a Leads to Abnormal Median Fin Development and Somitogenesis in Goldfish (Carassius auratus)

## TL;DR

This study shows that disrupting the lrp6a gene in goldfish causes abnormal fin development and skeletal issues, highlighting its role in Wnt signaling.

## Contribution

The study identifies lrp6a as essential for median fin development and somitogenesis in goldfish through CRISPR/Cas9 gene disruption.

## Key findings

- Disruption of lrp6a leads to defects in dorsal, caudal, and anal fins in goldfish.
- X-ray microtomography revealed skeletal deformities near the caudal peduncle in mutants.
- lrp6a shows tissue-specific expression differences between wen-type and egg-type goldfish.

## Abstract

In this study, we demonstrated that lrp6a, a co-receptor in the Wnt signaling pathway, is essential for proper median fin formation and somitogenesis in goldfish. We analyzed the gene’s sequence features and expression patterns in both wen-type and egg-type goldfish, uncovering distinct tissue-specific expression differences between the two varieties. To explore the functional role of lrp6a, we performed CRISPR/Cas9-mediated gene knockout using eight designed single-guide RNAs (sgRNAs), of which four showed effective targeting. Three high-efficiency sgRNAs were selected and co-injected into embryos to achieve complete gene disruption. Morphological assessments and X-ray microtomography (μCT) imaging of the resulting mutants revealed various abnormalities, including defects in the dorsal, caudal, and anal fins, as well as skeletal deformities near the caudal peduncle. These results confirm that lrp6a plays a key role in median fin development and axial patterning, offering new insights into the genetic regulation of fin formation in teleost fish.