Date of Award


Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)




Rebecca J. Van Beneden

Second Committee Member

Dorothy E. Croall

Third Committee Member

Keith W. Hutchinson


Environmental exposure to pollutants has been implicated in gonadal tumor formation in Maine softshell clams (Mya armaria). These germinomas have a prevalence as high as 40% in some populations with potential reproductive consequences. Investigations to determine the etiology and mechanisms involved in clam tumorigenesis have been based on a hypothesis of dioxin-induced disease progression. An assessment of changes in gene expression in response to dioxin exposure revealed the upregulation of a mRNA (Mya armaria E3; &E3) with significant sequence homology to E6AP, a HECT (homologous to E6AP carboxy terminus) E3 ubiquitin-protein ligase. E6AP is responsible for the abnormal degradation of the tumor suppressor p53