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Abstract

Cytochrome P450 aromatase (CYP19) is a key enzyme in the steroidogenic pathway that catalyses the
conversion of testosterone to estrogen, and therefore is thought to influence gonadal sex differentiation.
In an effort to understand the role of this enzyme in ovarian differentiation, we isolated cDNA encoding
the two distinct isoforms, ovarian and brain (termed cyp19a and cyp19b, respectively) of adult common
carp, Cyprinus carpio. The cloned cDNA for cyp19a had an open reading frame (ORF) of 518 amino acid
residues, in contrast to cyp19b with an ORF of 511 amino acids. Sequence and phylogenetic analysis
showed that these CYP19 isoforms were orthologous with previously described cyp19a and cyp19b from
other teleosts. Quantitative real-time PCR indicated that both isoforms are expressed in adult ovary and
brain, with predominant expression of cyp19a in the ovary and cyp19b in the brain. The major aromatase
expressing tissue was found to be the brain, with greatest cyp19b expression in the anterior quarter (telencephalon)
in both sexes. The gonad showed sexually dimorphic expression of both genes and dimorphic
expression of cyp19a was observed in the cerebellum and the liver. Ontogenic expression showed
that only the ovarian aromatase transcript is inherited maternally, with lower expression observed
through early larval development under warmer rearing conditions. The differential and overlapping
expression suggests these two aromatase genes have different roles in reproductive physiology.

Item Type:	Article
Authors/Creators:	Barney, M and Patil, JG and Gunasekera, RM and Carter, CG
Keywords:	Estrogenic pathway; Brain; Gonad; Sex differentiation; Quantitative real-time PCR; Reproduction
Journal or Publication Title:	General and Comparative Endocrinology
ISSN:	0016-6480
DOI / ID Number:	https://doi.org/10.1016/j.ygcen.2008.03.013
Additional Information:	The definitive version is available at http://www.sciencedirect.com
Item Statistics:	View statistics for this item

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