AUTHOR=Cai Lina , Zheng Jianbo , Jia Yongyi , Gu Zhimin , Liu Shili , Chi Meili , Cheng Shun 

TITLE=Molecular Characterization and Expression Profiling of Three Transformer-2 Splice Isoforms in the Redclaw Crayfish, Cherax quadricarinatus

JOURNAL=Frontiers in Physiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.00631

DOI=10.3389/fphys.2020.00631

ISSN=1664-042X

ABSTRACT=<p>Sex determination/sex differentiation is determined by genetics, environmental factors, or the interactions of the two. The <italic>Transformer-2</italic> (<italic>Tra-2</italic>) gene plays an important role in the sex determination cascade signal pathway in insects. In this study, the <italic>Tra-2</italic> gene was isolated and characterized from the cDNA library of gonad tissues in the redclaw crayfish, <italic>Cherax quadricarinatus.</italic> Three splice variants were identified, designated as <italic>CqTra-2A, CqTra-2B</italic>, and <italic>CqTra-2C</italic>, 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 <italic>Macrobrachium rosenbergii</italic>, <italic>Fenneropenaeus chinensis</italic>, and <italic>Macrobrachium nipponense.</italic> 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 <italic>CqTra-2</italic> 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 <italic>C. quadricarinatus.</italic> RNAi-targeting gene silencing further confirmed the function of <italic>CqTra-2</italic> in sexual differentiation in redclaw crayfish. Our experimental data will contribute to understanding the mechanism of sex determination in crustaceans.</p>