A Study of Exposure to Polycyclic Aromatic Hydrocarbons and Polymorphisms in the Tumor Suppressor Gene, p53, of Wild Menhaden

The British Petroleum (BP) Deep Water Horizon Oil spill in the Gulf of Mexico (GOM) caused detrimental effects to wildlife including marine fish populations (Diercks, et al. 2010). The fish were exposed to crude oil which contains polycyclic aromatic hydrocarbons (PAHs). Some PAHs are carcinogens and can damage DNA in key regulatory genes in various species (Milleman, et al. 2015; Nadler, 2017). Menhaden are oily, filter feeding fish and incorporate and retain these lipophilic contaminants at high levels. The objective of the present work was to search for genetic mutations on the tumor suppressor gene, p53, in various organs (gill, muscle, gonad, liver, and heart) of wild menhaden collected from two locations with differing proximity to the spill. Gulf Menhaden (Brevoortia patronus) were collected from the Vermillion (low oil exposure) and Grand Isle (heavy oil exposure) bay areas of the GOM. The DNA binding region of the p53 gene was amplified by PCR and Single-strand Conformational Polymorphism (SSCP) was utilized as an indicator of p53 mutations. P53 normally functions to inhibit cell division when excessive DNA damage is present. When mutated, cancer may result from uncontrolled cell growth. Fluorescence spectroscopy confirmed PAH- like compounds in almost all fish samples tested. The genomic analysis illustrates one sharp band at 360 bp which is consistent with the expected size of the DNA binding domain of p53, indicating a successful amplification of this gene. SSCP reveals one profile in all organ samples concluding low incidence of gene variation or single nucleotide polymorphisms