Abstract

Cytochrome P450 family 1 (CYP1A) subfamily genes are the most well studied CYP genes in vertebrates; however, information on CYP1A genes in Javanese medaka is relatively scarce. In the present study, full-length cDNA of CYP1A was cloned from the fish liver exposed to 500 ppb β-naphthoflavone for 24 h, which is 2439 bp contained in an open reading frame of 1593 bp encoding a protein of 530 amino acids. Real time polymerase chain reaction (RT-PCR) was used to measure the quantitatively tissue expression of the gene by environmental stress conditions. The results indicate that the highest levels of the CYP1A gene transcript was in intestine and the lowest in liver of the fish that fed on fuel oil-contaminated feed. Javanese medaka CYP1A transcripts were detected in the gill, muscle and intestine when transferred from seawater to freshwater with the highest level of expression in gill and muscle. CYP1A gene expression in the tissues tends to be down-regulated in Javanese medaka starved for one week.

Key words: Cytochrome P450, CYP1A, Javanese medaka, heavy fuel oil, salinity, starvation, cloning, expression.