大鼠肝癌中α_1-抑制因子3基因表达及基因结构的某些变化

THE EXPRESSION OF ALPHA 1-INHIBITOR 3 GENE AND SOME CHANGES OF ITS STRUCTURE IN RAT HEPATOMAS.

在DEN诱发的大鼠肝癌中,大部分(75%,12/16)肝癌组织中α_1-I 3的基因表达显著减少或失去表达能力。进一步的研究表明,该基因表达异常的原因可能部分地是由于基因的甲基化程度较高,及可能由于基因本身结构的变化(如重复序列的插入及在某些限制性内切酶位点发生突变)而导致基因结构异常(RFLP)有关。本文还就α_1-I 3类内源性蛋白酶抑制因子与癌变的关系进行了讨论。

The expression and structure of alpha 1-inhibitor 3 (α_1-I 3) gene were investigated in 16 primary rat hepatomas induced by diethylnitrosaminc. In most tumor samples (75%, 12/16),the expression, of α_1-I 3 gene manitested markedly diminished or undetectable level of α_1-I 3 mRNA. Further study indicated that the abnormal expression of α_1-I 3 gene in the hepatomas examined might be due to, at least in part, the gene hypermethylation,insertion of repeat sequence(s) or base substitutions at the recognition sequences of some restriction endonucleases which caused certain alteration in the gene structure. The significance of α_1-I 3 as an endogenous antitumor factor in hepatocarcinogenesis was also discussed.