Systematic analysis of Wnt family genes reveals the potential role of Wnt4 in driving female differentiation in Spotted knifejaw

Biochem Biophys Res Commun. 2025 Oct 20;785:152684. doi: 10.1016/j.bbrc.2025.152684. Epub 2025 Sep 18.

ABSTRACT

Wnt family genes encode secreted glycoproteins that regulate cell proliferation, differentiation, and organ growth. While much research has focused on species with standard chromosomal systems, there is a lack of studies on marine fish species like Spotted knifejaw (Oplegnathus punctatus), which possess a multiple sex chromosome system (X₁X₁X₂X₂/X₁X₂Y). We employed a combination of whole-genome scanning of the Wnt family, and qPCR analyses, RNAi knockdown to assess the specific contribution of wnt4 to female sexual development. We identified 16 Wnt genes in the Spotted knifejaw, with OpWnt2, OpWnt3, OpWnt4, OpWnt7, OpWnt8, OpWnt9, and OpWnt10 exhibiting two genotypes in females, while OpWnt4 and OpWnt9 had only one sequence in males. Phylogenetic analysis grouped the Wnt family into three clusters: OpWnt2/OpWnt5, OpWnt1/OpWnt6/OpWnt4, and OpWnt3/OpWnt8/OpWnt10/OpWnt7/OpWnt9/OpWnt11/OpWnt16. All members of the Wnt family contain a Wnt1 domain. Wnt4 showed higher expression in female ovaries (5-40 dph) compared to males and may act upstream of foxl2, which also regulates female differentiation. Chromosomal localization of Opwnt4 was found on female chromosome 3 and male heterozygous chromosome 1. Knockdown of wnt4 upregulated male-biased genes (amh, dmrt1, sox9a) while enhancing female-biased genes (foxl2, cyp19a, cyp19b), indicating that Opwnt4 synergistically regulates female differentiation and antagonizes male pathways. This study provides new insights into wnt4's role in sexual differentiation and lays the foundation for future research on sex chromosome systems in marine fish.

PMID:40997582 | DOI:10.1016/j.bbrc.2025.152684