Two novel CYP3A isoforms in marine mussel Mytilus coruscus: Identification and response to cadmium and benzo[a]pyrene

Area of Science:

• * Marine molecular biology and toxicology.
• * Biochemistry and environmental science.

Background:

• * Cytochrome P450 3A (CYP3A) enzymes are vital for xenobiotic metabolism in many organisms.
• * Limited information exists regarding CYP3A gene function and genetic makeup in molluscs.

Purpose of the Study:

• * To identify and characterize novel CYP3A genes in the mussel Mytilus coruscus.
• * To investigate the tissue distribution and expression patterns of these genes in response to environmental stressors.
• * To assess the potential of these genes as biomarkers for pollutant exposure.

Main Methods:

• * Identification and characterization of two novel CYP3A genes (McCYP3A-1 and McCYP3A-2).
• * Real-time quantitative RT-PCR (qRT-PCR) for gene expression analysis.
• * Erythromycin N-demethylase (ERND) assay to measure enzyme activity.
• * Exposure studies using cadmium (Cd) and benzo[a]pyrene (B[α]P).

Main Results:

• * McCYP3A-1 and McCYP3A-2 genes were identified, possessing characteristic CYP and CYP3 domains.
• * Transcripts were constitutively expressed across tissues, with high levels in digestive glands, hepatopancreas, and gonads.
• * Gene expression showed dynamic changes upon exposure to B[α]P and Cd, with Cd inducing a time-dependent response.
• * ERND activity increased over time following exposure to both Cd and B[α]P.

Conclusions:

• * McCYP3A-1 and McCYP3A-2 are identified as functional CYP3A members in Mytilus coruscus.
• * These genes are involved in xenobiotic metabolism and respond to environmental pollutants.
• * McCYP3A-1 and McCYP3A-2 show promise as candidate biomarkers for monitoring polycyclic aromatic hydrocarbons and heavy metal contamination.