Abstract:In order to preliminarily explore the function and molecular mechanism of Sex-lethal gene in Procambarus clarkii, four Sxl cDNA sequences from P. clarkii were cloned using rapid amplification of cDNA ends, and their expression in different tissues and early developmental stages were detected by quantitative fluorescence PCR. Bioinformatics analyses revealed that PcSxlβ and PcSxlδ had a 77 bp more base sequence than PcSxlγ, and the predicted amino acid sequence of PcSxlβ and PcSxlδ were shorter than that of PcSxlγ. The PcSxl sequences was highly similar to that of Cherax quadricarinatus (75.76%). The analysis of conservative domain showed that the amino acid sequences predicted by the four transcriptional isomers all had the same two highly conservative RRM domains. The expression analyses showed that PcSxl was highly expressed in the antennal glands and gills of adult males, and in the midgut and foregut of adult females, and was significantly higher in the female ovaries than the male testis. In the early developmental period of the crayfish, the expression was the highest in the period of nauplius stage, but decreased in the zoea stage; however, the expression level increased at the first day after hatching, and then showed a gradually decreasing trend as a whole. The results of this study suggested that PcSxl was associated with sexual differentiation in P. clarkii.