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This Article Accepted manuscript (PDF) All Versions of this Article: JOE-08-0303v1 199/2/317    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Zhang, Y. Articles by Zhang, L. Search for Related Content PubMed PubMed Citation Articles by Zhang, Y. Articles by Zhang, L.

Y Zhang, Biology Department, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
W Zhang, State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
H Yang, Biology Department, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
W Zhou, Biology Department, School of Life Sciences, Sun Yat-Sen University, Guangzhopu, China
C Hu, Chinese Academy of Sciences, South China Sea Institute of Oceanology, Guangzhou, China
L Zhang, Biology Department, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China

Correspondence: Lihong Zhang, Email: zhlih{at}mail.sysu.edu.cn

Abstract

Previously, the ricefield eel (Monopterus albus) was speculated to have only one cytochrome P450 aromatase gene. In this study, however, the cDNAs encoding two distinct cytochrome P450 aromatases, CYP19A1 and CYP19A2, were isolated. The genomic organizations of both CYP19 genes were conserved as compared to other teleosts. Northern blot detected an abundant expression of CYP19A1 in the ovary, and CYP19A2 in the hypothalamus. RT-PCR coupled with Southern blot showed that CYP19A1 was expressed predominantly in the gonads of both sexes, with higher levels in the ovary than testis, while CYP19A2 was expressed in all the tissues examined in the male, but only in the brain and pituitary in the female.

The levels of CYP19A1 mRNA in the ovary were increased significantly during vitellogenesis, but decreased significantly at mature stage. The levels of CYP19A2 mRNA in the brain and pituitary did not vary significantly during vitellogenesis. As ovarian development shifted from vitellogenesis to maturation, the levels of CYP19A2 mRNA was decreased significantly in the brain, but increased significantly in the pituitary. During natural sex change from female to male, the levels of CYP19A1 mRNA in the gonad were significantly decreased. The levels of CYP19A2 mRNA in the hypothalamus were significantly increased at the early intersexual phase, whereas the expression levels in the pituitary were significantly decreased at the intersexual phases. Taken together, these results showed a novel sexual dimorphism of CYP19A2 mRNA tissue distribution, and both CYP19 genes were associated with the ovarian development and natural sex change of ricefield eel.