The significant sex-biased expression pattern of Sp-Wnt4 provides novel insights into the ovarian development of mud crab (Scylla Paramamosain)

Int J Biol Macromol. 2021 Jul 31:183:490-501. doi: 10.1016/j.ijbiomac.2021.04.186. Epub 2021 May 3.

Abstract

The wingless-type MMTV integration site family member-4 (Wnt4), a member of the wingless-related integration site (Wnt) family, is widely accepted as a key regulator of ovarian development in mammals. In this study, a full-length cDNA of Wnt4 (designated as Sp-Wnt4) was cloned, characterized, and functionally studied in mud crab (Scylla paramamosain). The full-length cDNA of Sp-Wnt4 consists of 2659 bp with an open reading frame (ORF) encoding 359 amino acids, a 907 bp 5'-UTR and a 672 bp 3'-UTR. Sp-Wnt4 contains 25 cysteine (Cys) residues and three potential N-glycosylation sites. Sp-Wnt4 protein shared the highest identity (98.9%) to the Wnt4 protein of Portunus trituberculatus. The phylogenetic tree showed that Sp-Wnt4 and Wnt4 protein of Malacostracan crustaceans clustered together, indicating that they had a close genetic distance. Sp-Wnt4 was expressed at a higher level in the ovary compared to other tissues, with the highest expression level at the third stage (O-III) of the ovarian development (P < 0.05). A downward trend was observed in the expression level of Sp-Wnt4 from the embryo stage to crablet stages (P < 0.05). After unilateral eyestalk ablation, the expression level of Sp-Wnt4 significantly increased in testis (14-fold) and downregulated (3.1-fold) in the gill (P < 0.05) of females. In situ hybridization (ISH) assay revealed that Sp-Wnt4 transcripts were mainly localized in the cytoplasm of oocyte cells. These findings showed that Sp-Wnt4 play crucial roles in the ovarian development of S. paramamosain. In conclusion, our study provides novel insights into the evolution and roles of the Wnt4 gene.

Keywords: Eyestalk ablation; Sexual differentiation; Wnt signalling.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Brachyura / genetics
  • Brachyura / growth & development
  • Brachyura / metabolism*
  • Evolution, Molecular
  • Female
  • Gene Expression Regulation, Developmental
  • Male
  • Ovary / growth & development
  • Ovary / metabolism*
  • Phylogeny
  • Sex Characteristics
  • Sex Differentiation
  • Wnt4 Protein / genetics
  • Wnt4 Protein / metabolism*

Substances

  • Wnt4 Protein