Molecular characterization and gene expression profile of <i>Foxl2</i> in the <i>Cherax quadricarinatus</i>

Foxl2 (Forkhead box protein L2), a forkhead transcription factor, plays a pivotal role in the ovarian development of aquatic species. However, the biological function of Foxl2 in Cherax quadricarinatus remains underexplored. In this study, the full-length cDNA of Cq-Foxl2, comprising 2,325 bp, was characterized, with a 1,695 bp open reading frame (ORF) encoding a protein of 564 amino acids. Bioinformatics analysis revealed that the predicted amino acid sequence of Cq-Foxl2 contained a conserved forkhead box domain, exhibiting high homology with other crustaceans, particularly Procambarus clarkii . qRT-PCR analysis indicated that Cq-Foxl2 was predominantly expressed in the ovary, with minimal detection in other tissues. Expression levels of Cq-Foxl2 were abundant throughout different stages of ovarian development. Moreover, RNAi-mediated silencing of Cq-Foxl2 led to a significant reduction in the transcription of Cq-Dsx and a decrease in the gonadosomatic index of female C. quadricarinatus . These findings offer essential insights for further exploration of the role of Cq-Foxl2 in ovarian development.