Expression of genes for alcohol and aldehyde metabolizing enzymes in mouse oocytes and preimplantation embryos.
Alcohols and aldehydes are metabolized primarily by alcohol (ADH) and aldehyde (ALDH) dehydrogenase isozymes. Although significant progress has been made towards understanding the involvement of these isozymes in the oxidation of alcohol and aldehydes in the body, it is not known how these compounds are handled during fertilization and preimplantation embryogenesis. In this study, reverse transcription and the polymerase chain reaction (RT-PCR) was used to determine which ADH and ALDH isozymes are expressed at the oocyte, zygote, morula, and blastocyst stages of preimplantation development in the mouse. Transcripts of beta-actin and vimentin, assayed as controls, were detected at all stages, as well as Class III ADH (Adh-2) and Class 3 ALDH (Ahd-4), involved in the detoxification of formaldehyde and aromatic aldehydes, respectively. In contrast, transcripts for the major ethanol oxidizing isozyme, Class I ADH (Adh-1) was not detected during preimplantation development. Cytosolic retinol dehydrogenase (Adh-3) transcripts were marginally detected in oocytes and zygotes. The mRNA for cytosolic retinal dehydrogenase (Ahd-2), microsomal short-chain retinol dehydrogenases (RoDH Type I), and the mitochondrial low-Km acetaldehyde dehydrogenase (Ahd-5) only appeared as maternal transcripts. Microsomal ALDH (Ahd-3), which is induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), was not expressed until the blastocyst stage. ADH and ALDH enzyme systems may guard mouse preimplantation embryos against the toxic effects of industrial pollutants, such as formaldehyde and TCDD, as well as peroxidatic aldehydes generated during lipid peroxidation. The absence of enzymes to convert ethanol to acetaldehyde, coupled with oocyte expression of the acetaldehyde-degrading enzyme, Ahd-5, may be protective for the early embryo.
Department of Obstetrics & Gynecology, C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, 275 East Hancock, Detroit, MI 48201, USA. aa4306@wayne.edu
Ujjwal Kumar
UK
Rout
D Randall
DR
Armant
D000199:Actins / Q000235:genetics / Q000378:metabolism; D000426:Alcohol Dehydrogenase / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D000444:Aldehyde Dehydrogenase / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001755:Blastocyst / Q000201:enzymology*; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D018507:Gene Expression Regulation, Developmental; D007527:Isoenzymes; D051379:Mice; D009865:Oocytes / Q000201:enzymology*; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000235:genetics; D014746:Vimentin / Q000235:genetics / Q000378:metabolism
D000199:Actins; D017931:DNA Primers; D007527:Isoenzymes; D012333:RNA, Messenger; D014746:Vimentin; D000426:Alcohol Dehydrogenase; D000444:Aldehyde Dehydrogenase