大鼠血清白蛋白基因的分离、鉴定和表达以及在急性炎症期间大鼠血清白蛋白mRNA水平的变化

ISOLATION,CHARACTERIZATION AND EXPRESSION OF GENE FOR RAT SERUM ALBUMIN,AND CHANGES OF ITS mRNA LEVEL DURING ACUTE INFLAMMATION

利用表达载体λgT11Amp3以大鼠肝 mRNA 建立了一个 cDNA 文库,从中分离了表达大鼠血清白蛋白抗原决定簇的克隆。内切酶作用图谱和 DNA 顺序测定法表明最大的插入子含有成熟白蛋白的完整编码顺序。聚丙烯酰胺凝胶电泳和免疫检测表明所表达的蛋白质是和细菌β-半乳糖苷酶一起以融合蛋白质的形式存在的。以 DNA-RNA 杂交法用P 标记的血清白蛋白 cDNA 进行测定,表明在急性炎症期间,大鼠肝中的白蛋白 mRNA 水平大大下降。

The expression vector λgTllAmp3 has been used to constructa cDNA library from rat liver mRNA.Twenty independent clones,expres-sing antigenic determinants to rat albumin;were isolated.The sizes of the cDNAinsertrons for these clones varied from 0.9 to 1.9 kb.Three of them(clone 4,12,21)were further identified by restriction mapping and DNA sequencing.The lar-gest insertron contained the entire coding sequence for mature albumin.Observa-tion of the expressed proteins by polyacrylamide gel electrophoresis followed byimmunological detection indicated that the proteins were produced as hybrids lin-ked to the bacterial β-galactosidase.TheP-labelled cDNA for albumin was used to measure mRNA levels by DNA-RNA hybridization,During acute inflammation,the level of the albuminmRNA in ratliver decreased,reaching the minimum of 25% of the normal level36h after inducing inflammation.