Foxl2 of the Hong Kong catfish (Clarias fuscus): cDNA cloning, tissue distribution and changes in gene expression towards methyltestosterone, estradiol and letrozole exposure of the fries during gonadal differentiation

• Published in: Genes & genomics Vol. 37; no. 8; pp. 669 - 677
• Main Authors: Deng, S., Guangdong Ocean University, Zhanjiang, China, Zhu, C., Guangdong Ocean University, Zhanjiang, China, Sun, J., Guangdong Ocean University, Zhanjiang, China, Wang, W.D., Guangdong Ocean University, Zhanjiang, China, Wu, T., Guangdong Ocean University, Zhanjiang, China, Chen, H., Guangdong Ocean University, Zhanjiang, China, Shi, S., Guangdong Ocean University, Zhanjiang, China, Li, G., Guangdong Ocean University, Zhanjiang, China
• Format: Journal Article
• Language: English
• Published: Seoul The Genetics Society of Korea 01.08.2015; 한국유전학회
• Subjects: Animal Genetics and Genomics; Biomedical and Life Sciences; CLARIAS FUSCUS; Human Genetics; Life Sciences; Methyltestosterone, Estradiol, Letrozole, foxl2; Microbial Genetics and Genomics; Plant Genetics and Genomics; Research Article; Teleostei; 생물학; Methyltestosterone; Estradiol; Letrozole
• ISSN: 1976-9571; 2092-9293
• DOI: 10.1007/s13258-015-0296-z

Winged helix/forkhead transcription factor gene 2 (Foxl2) plays a crucial role during early ovarian development in fish. Sex steroids and aromatase inhibitors can regulate gonadal differentiation in teleosts. To address the role of Foxl2 in gonadal differentiation, foxl2 was isolated and characterized from the Hong Kong catfish, Clarias fuscus. Tissue distribution analysis by quantitative real-time PCR (qPCR) showed that the foxl2 mRNA was highest in the ovaries; moderate in the female pituitary and hypothalamus; but weak in the forebrain, liver, testis and male pituitary, with a sexually dimorphic pattern in which there was higher expression overall in females versus males. Treatment of the fries during the period of gonadal differentiation [2 - 30 days post hatching (dph)] with 17amethyltestosterone (MT), an aromatase inhibitor (letrozole) and 17b-estradiol (E2) affected the expression of foxl2. The expression of foxl2 was highest before gonadal differentiation (12 dph), but decreased significantly after gonadal differentiation (18-30 dph). In addition, MT and letrozole were able to down-regulate foxl2, but E2 up-regulated foxl2 during gonadal morphological differentiation. These results indicate the significant roles of Foxl2 in the gonadal differentiation of C. fuscus.