Sexually Dimorphic Expression of Foxl2 and Ftz-F1 in Chinese Giant Salamander Andrias Davidianus.

ABSTRACT Foxl2 and FTZ-F1 play a crucial role in the regulation of gonad development in fish and mammals, but studies of their function in amphibians are scarce. We isolated the full length of Foxl2 ( adFoxl2) and Ftz-F1 ( adFtz-f1) cDNA from the Chinese giant salamander Andrias davidianus and quantified its expression in various tissues and developing gonads. The adFoxl2 gene encodes 301aa including a conserved forkhead box, and the adFtz-f1 gene encodes 467aa containing an Ftz-F1 box. The amino acid sequences showed high homology with other amphibians. adFoxl2 expression was high in ovary, whereas adFtz-f1 was higher in testis, moderate in pituitary, ovary, and kidney; and low in the remaining tested tissues. Expression of adFoxl2 gradually increased from 1Y to 5Y in ovary, whereas adFtz-f1 expression gradually decreased in testis. In addition, adFoxl2 and adFtz-f1 were detected in granulosa cell in ovary and in spermatocytes in testis. The adFoxl2 transcription was inhibited in brain and ovary after treatment with methyltestosterone and with letrozole, whereas adFtz-f1 expression was upregulated. High-temperature suppressed the expression of adFxl2 in ovary and enhanced the transcription of adFtz-f1. These results suggest that adFoxl2 functioned in ovary differentiation, whereas adFtz-f1 played a role in testis development, which lays a foundation for study of the sex differentiation mechanism in A. davidianus. [ABSTRACT FROM AUTHOR]