# Migration of Kupffer's vesicle-derived cells is essential for tail morphogenesis in zebrafish embryos

## TL;DR

A study found that the movement of cells from Kupffer's vesicle is crucial for proper tail development in zebrafish embryos.

## Contribution

The study reveals that Kupffer's vesicle-derived cells have tail progenitor capacity and their migration is essential for normal tail formation.

## Key findings

- Geraniol, a monoterpene alcohol, induces ectopic tail formation in zebrafish embryos.
- Kupffer's vesicle-derived cells fail to migrate after geraniol treatment, leading to an ectopic tail.
- Ablation of Kupffer's vesicle rescues ectopic tail formation, confirming its role in tail morphogenesis.

## Abstract

A phenotypic screen of fungal filtrates on developing zebrafish embryos identified metabolites from the fungus Ceratocystis populicola to induce ectopic tail formation, including a split notochord and a duplicated caudal fin. Chemical analyses led to the identification of monoterpene alcohols, in particular geraniol, as the active compounds. Tüpfel long fin zebrafish embryos were more susceptible to geraniol-induced ectopic tail formation than Wild Indian Karyotpe zebrafish embryos. RNA-sequencing on tail buds of 15-somite-stage embryos revealed downregulation of essential genes of the retinoic acid signaling pathway. Differential expression of cyp26a1, fgf8a and downstream hox-genes was validated. Time-lapse imaging revealed that Kupffer's vesicle-derived cells failed to migrate after Kupffer's vesicle collapse upon geraniol treatment. These cells failed to merge with progenitors from the tail bud and contributed to an ectopic tail, expressing markers for presomitic mesoderm, somite and notochord tissue. Strikingly, ablation of Kupffer's vesicle by tbxta-morpholino injection rescued ectopic tail formation. Taken together, our data suggest that Kupffer's vesicle cells harbor tail progenitor capacity, and proper migration of these cells is essential for normal tail morphogenesis.

Summary: Inhibition of Kupffer's vesicle-derived cell migration affected tail morphogenesis and resulted in ectopic tail formation in zebrafish embryos.