CHARACTERIZATION OF APOLIPOPROTEIN-B MESSENGER-RNA EDITING FROM RABBIT INTESTINE

被引：35

作者：

GARCIA, ZC ^{[1
]}

POKSAY, KS ^{[1
]}

BOSTROM, K ^{[1
]}

JOHNSON, DF ^{[1
]}

BALESTRA, ME ^{[1
]}

SHECHTER, I ^{[1
]}

INNERARITY, TL ^{[1
]}

机构：

[1] UNIV CALIF SAN FRANCISCO, GLADSTONE FDN LABS CARDIOVASC DIS, CARDIOVASC RES INST, POB 40608, SAN FRANCISCO, CA 94140 USA

来源：

ARTERIOSCLEROSIS AND THROMBOSIS | 1992年 / 12卷 / 02期

关键词：

RNA PROCESSING; APOLIPOPROTEIN-B; RNA EDITING; APOLIPOPROTEIN-B-48;

D O I：

10.1161/01.ATV.12.2.172

中图分类号：

R5 [内科学];

学科分类号：

1002 ; 100201 ;

摘要：

Apolipoprotein (apo) B-48 is generated by a unique physiological process. Cytidine 6,666 of the apo B primary transcript is posttranscriptionally converted to a uridine by an RNA editing mechanism that transforms the codon for glutamine 2,153 to a termination codon. The editing reaction can be duplicated in a cell-free extract. In this study, the apo B-48 mRNA editing activity derived from partially purified extracts of rabbit enterocytes was characterized. The optimum conditions for the editing reaction were determined to be a salt concentration of 0.125-0.150 M NaCl or KCl a pH of 8-8.5, and a temperature of 30-degrees-C. The reaction rate was linear up to 45 minutes and was proportional to the editing extract concentration. No metal ion cofactors, DNA or RNA cofactors, or energy requirements were identified. At optimum conditions, the reaction followed Michaelis-Menten kinetics, with a K(m) of 0.4 nM for the rabbit RNA substrate. In addition, the reaction rate was enhanced by the addition of 25-mu-g/ml heparin or 40% glycerol. The characteristics of the editing reaction suggest that it is catalyzed by a nucleotide sequence-specific cytidine deaminase that is either a single enzyme or a multimeric protein.

引用

页码：172 / 179

页数：8

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