Detection of a smaller, 32‐kDa 8‐oxoguanine DNA glycosylase 1 in 3′‐methyl‐4‐dimethylamino‐azobenzene‐treated mouse liver

• Published in: Cancer science Vol. 95; no. 2; pp. 118 - 122
• Main Authors: Hirano, Takeshi, Kudo, Hideaki, Doi, Yoshiaki, Nishino, Tomoko, Fujimoto, Sunao, Tsurudome, Yosuke, Ootsuyama, Yuko, Kasai, Hiroshi
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2004; John Wiley & Sons, Inc
• Subjects: Animals; Base excision repair; Blotting, Western; Carcinogenesis; Deoxyribonucleic acid; DNA; DNA Damage - genetics; DNA glycosylase; DNA Glycosylases - biosynthesis; DNA Repair; Epitopes; Gene Expression; Guanine - analogs & derivatives; Immunoblotting; Immunohistochemistry; Liver; Liver Neoplasms - chemically induced; Liver Neoplasms - enzymology; Liver Neoplasms - genetics; Localization; Mice; Nuclear Localization Signals - genetics; OGG1 protein; p-Dimethylaminoazobenzene - analogs & derivatives; p-Dimethylaminoazobenzene - toxicity; Polyclonal antibodies; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - analysis; Rodents
• ISSN: 1347-9032; 1349-7006
• DOI: 10.1111/j.1349-7006.2004.tb03191.x

We previously reported that 3′‐methyl‐4‐dimethylaminoazobenzene (3′‐MeDAB) increased the 8‐hydroxyguanine (8‐OH‐Gua) content in nuclear DNA and the base excision repair activity in mouse liver. However, to understand the mechanism of 3′‐MeDAB carcinogenesis, a further investigation of the 8‐OH‐Gua repair systems was necessary. In this report, we examined the expression of the repair enzyme, 8‐oxoguanine DNA glycosylase 1 (OGG1), in 3′‐MeDAB‐treated mouse liver. We prepared four kinds of anti‐peptide polyclonal antibodies raised against mouse OGG1 (mOGG1). The sequences used as epitopes were designed from positions located close to the N‐terminus, the nuclear localization signal (NLS), and the regions containing Lys249 and Asp267, which are involved in the catalytic mechanisms of mOGG1 (glycosylase and lyase, respectively). Immunoblotting, using all four antibodies, revealed a 32‐kDa protein (mOGG1‐32) in addition to the 38‐kDa mOGG1 in the 3′‐MeDAB‐treated mouse liver. Moreover, immunostaining with mOGG1 antibody yielded strong, positive signals in the 3′‐MeDAB‐treated mouse liver nuclei. However, we could not detect any difference in the Ogg1 mRNA expression pattern. Although the function of mOGG1‐32 remains unclear, these findings suggest that 3′‐MeDAB may alter the function of the DNA repair protein, and this action may be related to 3′‐MeDAB carcinogenesis.