Identification and Expression Analysis of Wnt2 Gene in the Sex Differentiation of the Chinese Soft-Shelled Turtle ( Pelodiscus sinensis )

The Chinese soft-shelled turtle ( ) is an important freshwater aquaculture animal in China. The gene family plays important regulatory roles in the development and growth of mammals. However, the precise function of these family genes has not been well understood in the sex differentiation of Chinese soft-shelled turtles. Here, we cloned a member of the Wnt family, , which obtained a 1077 bp open reading frame that encoded a 358-aa protein. The putative amino acid sequences of proteins are exceeded 80% identical to other turtles. The expression level of peaked at the 14th stage both in female and male embryos during the early gonadal differentiation period of Chinese soft-shelled turtles, which occurred before gonadal differentiation. mRNA was expressed at higher levels in the brains and gonads of mature females compared with those in mature males. Wnt agonists significantly affected the expression level of during the gonadal differentiation period. After Wnt agonists (1.0 μg/μL, 2.5 μg/μL, 5.0 μg/μL) treatment, the expression level of the generally appeared to have an inverted-V trend over time in female embryonic gonads. The results suggested that may participate in the regulation of gonad development in during the early embryonic stages. These results could provide a theoretical basis for the reproduction process of the Chinese soft-shelled turtle.