Date of Award
1992
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Abstract
The influence of genetic factors on alcoholism and relative sensitivity to alcohol has been recognized but remains elusive. In mammals, ethanol is primarily oxidized by alcohol dehydrogenase (ADH) to form acetaldehyde. Acetaldehyde is the toxic metabolite responsible for most alcohol-related adverse effects. Acetaldehyde dehydrogenase (ALDH) irreversibly oxidizes acetaldehyde to acetate. Individuals with a mutant allele for mitochondrial ALDH experience a severe reaction to ethanol, caused by elevated acetaldehyde levels. Also, C57BL/6J, alcohol preferring mice are reported to have increased ALDH enzyme activity after ethanol feeding while BALB/c and 129/ReJ (alcohol avoiding) mice do not. The significance of ALDH in regulating the relative level of acteldehyde and the adverse effects of ethanol consumption is now well recognized.;The genes of alcohol metabolism in strains of mice with variable ethanol responses were examined. C57BL/6J mice showed increased Adh-1 and Ahd-2 mRNA, BALB/c mice a small increase in Adh-1 mRNA and no change in Ahd-2 mRNA, while 129/ReJ mice had decreased levels of both mRNA species after ethanol challenge. The increased levels of Ahd-2 mRNA in C57BL/6J mice after ethanol consumption correlated to the reported increases in AHD-2 enzyme activity. Furthermore, a correlation between ethanol preference of the strains and banding patterns on Southern blots produced by hybridization with a partial cDNA probe for Ahd-2 was noted.;The complete cDNA for Ahd-2 was sequenced and includes 1503 nucleotides coding for 501 amino acids. Two regions of the Ahd-2 gene were sequenced and compared among the three strains studied. Only minor differences were observed in both the promoter and Antabuse binding regions. Variable responses to ethanol in these strains cannot be explained by the observed DNA sequence differences observed. Promoter region analysis revealed a number of possible enhancer binding sequences. Binding of proteins to these sequences and possible effects of ethanol on transcriptional regulation in the strains are not known. Partial sequence of an additional gene, 'Ahd-2 related', 90.8% identical to Ahd-2 was obtained. Its function in ethanol metabolism and sensitivity, however, remains to be determined.
Recommended Citation
Bond, Shari Lynne, "Cytosolic Acetaldehyde Dehydrogenase (ahd-2) In Mice:cdna Sequence, Molecular Characterization And A Possible Role In Ethanol Sensitivity" (1992). Digitized Theses. 2079.
https://ir.lib.uwo.ca/digitizedtheses/2079