Abstract
Sex determination/sex differentiation is determined by genetics, environmental factors, or the interactions of the two. The Transformer-2 (Tra-2) gene plays an important role in the sex determination cascade signal pathway in insects. In this study, the Tra-2 gene was isolated and characterized from the cDNA library of gonad tissues in the redclaw crayfish, Cherax quadricarinatus. Three splice variants were identified, designated as CqTra-2A, CqTra-2B, and CqTra-2C, and sequence analysis showed that they had a highly conserved RRM domain. Phylogenetic analysis was performed by the NJ method, and the results revealed that the Tra-2 protein of the redclaw crayfish was very closely related to those of Macrobrachium rosenbergii, Fenneropenaeus chinensis, and Macrobrachium nipponense. Real-time PCR analysis showed that the three isoforms were predominantly expressed in the ovary and gradually increased with embryonic development. Additionally, the expression pattern of CqTra-2 at different developmental stages was analyzed by qPCR and revealed that the phase of having a body length of 3 cm may be the key period for the sex differentiation of C. quadricarinatus. RNAi-targeting gene silencing further confirmed the function of CqTra-2 in sexual differentiation in redclaw crayfish. Our experimental data will contribute to understanding the mechanism of sex determination in crustaceans.
Highlights
Decapod aquaculture is one of the most important economic industries in China and brings large benefits to farmers
By searching homologous sequences submitted to the NCBI GenBank, the full-length cDNA sequence of Tra-2 was obtained from the transcriptome database constructed in our lab and validated by Sanger sequencing
The full-length cDNA sequences of three CqTra2 isoforms were obtained from the transcriptome library of gonadal tissues of C. quadricarinatus, which is a homolog of the sex differentiation protein Tra and is involved in the sex determination pathway in D. melanogaster (Inoue et al, 1990; Penalva and Sanchez, 2003; Sarno et al, 2010)
Summary
Decapod aquaculture is one of the most important economic industries in China and brings large benefits to farmers. In crustaceans, many biological or economic traits exist that are significantly different between males and females, such as growth rate and body size (Sagi et al, 1986; Browdy, 1998; Yu et al, 2017). The molecular mechanism of sex determination and differentiation in crustaceans is highly complex and currently remains poorly understood, which is likely due to the rapid evolution of genes involved in this process (Zhang and Qiu, 2010). A body of evidence demonstrates that the insulin-like androgenic gland hormone gene (IAG) is the key factor that drives male sexual differentiation in crustacean species (Sagi et al, 1990; Shi et al, 2019). Several female sexual differentiation genes, foxl, fem, and cfsh, have been investigated in different crustacean species (Ma et al, 2016; Jin et al, 2018; Jiang et al, 2020)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
