title: Brain and liver targeted overexpression of O6-methylguanine DNA methyltransferase in transgenic mice.
abstract: O6-Methylguanine DNA methyltransferase (MGMT; EC 2.1.1.63) is an unusual DNA repair protein in that it directly and specifically repairs a premutagenic DNA lesion without involving other proteins. MGMT removes the alkyl group from O6-alkylguanine in DNA in a unique stoichiometric reaction by accepting the alkyl group on a cysteine residue. The intracellular level of MGMT varies among tissues and appears to be inversely correlated to tissue-specific tumorigenesis induced by monofunctional alkylating agents. Because MGMT acts in solo, genetic manipulation of its expression may provide valuable insight into its contribution to cellular resistance to alkylation toxicity and to tumor induction. The human MGMT full length cDNA has been fused with a portion of the human transferrin (TF) 5'-flanking region (TF/MGMT). Transgenic founder mice were produced carrying the TF/MGMT transgene and then bred to establish stable transgenic lines. Human MGMT transcripts were specifically expressed in abundance in transgenic brain and liver tissues. In vitro MGMT assays revealed approximately 150-fold and approximately 25-fold increases in MGMT activity in transgenic brain and liver extracts respectively. Western blot analysis confirmed that human MGMT protein is specifically synthesized in transgenic brain and liver tissues.
authors.affiliation: Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio 78284-7762.
authors.forename: C A
authors.initials: CA
authors.lastname: Walter
authors.forename: J
authors.initials: J
authors.lastname: Lu
authors.forename: M
authors.initials: M
authors.lastname: Bhakta
authors.forename: S
authors.initials: S
authors.lastname: Mitra
authors.forename: W
authors.initials: W
authors.lastname: Dunn
authors.forename: D C
authors.initials: DC
authors.lastname: Herbert
authors.forename: F J
authors.initials: FJ
authors.lastname: Weaker
authors.forename: T
authors.initials: T
authors.lastname: Hoog
authors.forename: P
authors.initials: P
authors.lastname: Garza
authors.forename: G S
authors.initials: GS
authors.lastname: Adrian
mesh_terms: D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology*; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D006801:Humans; D008099:Liver / Q000201:enzymology*; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic / Q000235:genetics* / Q000378:metabolism*; D008845:Microinjections; D008969:Molecular Sequence Data; D019853:O(6)-Methylguanine-DNA Methyltransferase; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D014168:Transferrin / Q000235:genetics
chemical_list: D014168:Transferrin; D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase