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Effects of Crude Oil on Tumor Suppressor P53 Polymorphisms in Laboratory
Exposed Killifish
Authors: Allison M. Nadler and Carolyn S. Bentivegna
Polycyclic aromatic hydrocarbons (PAH), constituents of crude oil, are implicated as a
potent source of adverse toxicological effects on living organisms. To model the effects of
PAHs in response to environmental oil spill disasters a species of killifish (Fundulus
heteroclitus) was captured and exposed to crude oil in a lab-controlled setting. Over a
period of 7 days fish were dosed with crude oil by gavage, culled, and organs were
harvested for analysis. Excitation-emission matrix spectroscopy (EEMS) on gall bladder
tissue homogenates was used to verify exposure. Effects of PAH on the p53 gene were
evaluated as an indicator of genotoxicity. P53 is a tumor suppressor protein that when
mutated is implicated in a variety of cancers and genomic instability. Specifically, the p53
DNA binding domain of the gene was amplified from liver tissue and analyzed using gel
electrophoresis and single-stranded conformational polymorphism (SSCP) gels. SSCP
showed that across control and treated killifish, seven unique genetic profiles could be
identified, indicating native polymorphisms. EEMS analysis on samples from days 3 and 7
confirmed PAH exposure. Several experimental profiles found in both control and treated
fish were cloned and resubjected to SSCP. Results showed masked polymorphisms in
treated but not control fish. Subsequent DNA sequencing of clones showed multiple point
nucleotide changes associated with different SSCP profiles. These findings support the
possible occurrence of crude oil-related mutagenesis in critical gene targets in response to
PAH exposure.
Allison M. Nadler
Seton Hall University
E-mail
[email protected]
Phone Number
(973) 4762933