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Analysis of gene abnormalities in newly found rats with congenital defect of alcohol metabolism.

新发现先天性酒精代谢缺陷大鼠基因异常分析

基本信息

批准号：
06670568
负责人：
KOHGO Yutaka
金额：
$ 1.41万
依托单位：
Asahikawa Medical College (1995)Sapporo Medical University (1994)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

Long Evans Cinamon (LEC) and Long Evans Agouti (LEA) rats are mutant strains established from Long Evans rats. LEC rats display hereditary hepatitis and spontaneous hepatocellular carcinoma. We preveously found that both LEA and LEC rats fed with liquid diet containing 5% ethanol died within 2 weeks owing to acute ethanol intoxication. In the present study, the molecular abnormalities of ethanol metabolism on these strains were elucidated. Enzymatic activities of both alcohol dehydrogenase (ADH) and acetaldehyde deheydrogenase (ALDH) were decreased at the level of 60-75% of the control Wistar rats. Nucleotide sequence analysis of both LEC and LEA rat liver ALDH RNA (exon 3 of ALDH-2) showed that there was a point mutation ; CAG to CGG at codon 67, indicating the presence of variant low Km ALDH as seen in human oriental people. In addition to ALDH point mutation, ADH gene also showed an abnormality in the first intron of class 1 ADH gene. The sequence length of TG repeat was 98 base pairs, while that of control Wistar rat was 80 base pairs. This result suggests that the insertion of TG repeat was present in LEC rat and may be responsible for the reduction of transcriptional efficiency of ADH gene. In contrast, by Western blot analysis, cytochrome P450 expression 2E1 (MEOS activity) was induced 8 times higher by ethanol feeding in LEC rat, which is normal response.

Long Evans Cinamon（LEC）和Long Evans Agglutinus（莱亚）大鼠是从Long Evans大鼠建立的突变品系。LEC大鼠显示遗传性肝炎和自发性肝细胞癌。我们以前发现，莱亚和LEC大鼠喂养含5%乙醇的液体饲料，由于急性乙醇中毒，在2周内死亡。在本研究中，这些菌株的乙醇代谢的分子异常进行了阐述。乙醇脱氢酶（ADH）和乙醛脱氢酶（ALDH）的酶活性均降低到对照组Wistar大鼠的60-75%。LEC和莱亚大鼠肝ALDH RNA（ALDH-2的外显子3）的核苷酸序列分析显示，在密码子67处存在点突变; CAG至CGG，表明存在人类东方人中所见的变体低Km ALDH。除ALDH点突变外，ADH基因第一内含子也存在异常。TG重复序列长度为98 bp，对照组为80 bp。这一结果提示，LEC大鼠存在TG重复序列的插入，可能是ADH基因转录效率降低的原因。与此相反，通过Western blot分析，在LEC大鼠中，乙醇喂养诱导细胞色素P450表达2 E1（MEOS活性）高8倍，这是正常反应。