IDENTIFICATION, EXPRESSION AND SEQUENCE ANALYSIS OF THE GENE CYP19A1A IN THE OVARY OF INDIAN MAJOR CARP CATLA CATLA THROUGHOUT A REPRODUCTIVE CYCLE AND IN THE EXTRAGONADAL TISSUESRose Gregoria P.J. and Moses Inbaraj R.
Aromatase is an enzyme responsible for a key step in the biosynthesis of estrogens, a product of a unique gene called cyp19. Catlacatla like other teleosts, expresses cyp19a1a gene mainly in the ovary, responsible for the production of aromatase enzyme. The abundance of the mRNA encoding cyp19a1a was determined by rtqRT-PCR in the tissues of the ovary of catla fish throughout the annual reproductive cycle. The expression of cyp19a1a has seen its peak level during the previtellogenic and vitellogenic period and the expression was very law during the time of resting period or postvitellogenic period. The expression level was prominent in the preparatory period, but it is lesser than previtellogenic and vitellogenic period. The expression of cyp19a1a is also seen in other tissues of brain, kidney, intestine, liver and gill. There was no expression of cyp19a1a in the male gonad. It confirms the significant role of this gene in the ovarian differentiation and in the different phases of reproductory cycle of C. catla. Phylogenetic results indicate that the gene cyp19a1a is evolutionally conserved throughout the vertebrate phyla.