Transcription of a novel P450 gene varies with some factors (pollutant exposure, temperature, time, and body region) in a marine oligochaete (Thalassodrilides sp.)

•A marine oligochaete had a high tolerance to PAH-polluted sediment.•A novel CYP gene was identified from an oligochaete.•Its mRNA expression was increased by exposure to PAH-polluted sediment.•The mRNA expression levels varied with exposure time and temperature.

Cytochrome P450 (CYP) enzymes play important roles in the metabolism of exogenous compounds such as polycyclic aromatic hydrocarbons (PAHs). A novel, full-length CYP gene (CYP4V30) was identified in the oligochaete Thalassodrilides sp. CYP4V30 mRNA expression was studied in worms exposed to PAH-polluted (Σ16PAHs; 37441 ng/g dry weight) or unpolluted (Σ16PAHs; 19 ng/g dry weight) sediment. CYP4V30 expression was much higher in worms exposed to contaminated sediments than in those exposed to unpolluted sediments at some temperatures (20 and 25 °C) and exposure durations (11-fold increase at 20 °C, 10-day exposure), but not at 15 °C or other exposure durations (P < 0.05). CYP4V30 mRNA expression was higher in the middle of the body than in the posterior (P < 0.05). The variation in transcriptional response with exposure time, temperature, and body region indicates that these factors should be considered when monitoring marine sediment pollution.