A NOVEL FORM OF TISSUE-SPECIFIC RNA PROCESSING PRODUCES APOLIPOPROTEIN-B48 IN INTESTINE
A NOVEL FORM OF TISSUE-SPECIFIC RNA PROCESSING PRODUCES APOLIPOPROTEIN-B48 IN INTESTINE
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DOI：
10.1016/0092-8674(87)90510-1
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发表时间：
1987-09-11
期刊：
影响因子：
64.5
通讯作者：
SCOTT, J
中科院分区：
文献类型：
--
作者：
POWELL, LM;WALLIS, SC;SCOTT, J
有证据表明，肠道apo-B48与肝脏apo-B100的氨基末端一半共线。为了研究apo-B48产生的机制，我们检测了人和兔小肠的cDNA克隆。所有克隆均含有单个C →。T碱基与肝脏序列的差异，导致翻译终止于密码子2153。通过聚合酶链反应扩增人和兔小肠、兔肝脏和人肝癌细胞系HepG2的cDNA，结果表明终止密码子仅存在于肠mRNA中。肠细胞基因组DNA不含终止密码子。我们建议，一个共同或转录后C。U改变可能导致apo-B48的产生，其代表apo-B100的氨基端2152个氨基酸。这是第一个组织特异性修饰单个mRNA核苷酸的例子，导致来自同一初级转录物的两种不同蛋白质。
Evidence suggests that intestinal apo-B48 is colinear with the amino-terminal half of hepatic apo-B100. To investigate the mechanism of apo-B48 production, we examined cDNA clones from human and rabbit small intestine. All clones contained a single C .fwdarw. T base difference from the hepatic sequence, resulting in a translational stop at codon 2153. Amplification by the polymerase chain reaction of cDNA from human and rabbit small intestine, rabbit liver, and the human hepatoma cell line HepG2 showed that the stop codon was only present in intestinal mRNA. Enterocyte genomic DNA did not contain the stop codon. We suggest that a co- or posttranscriptional C .fwdarw. U change may result in the production of apo-B48, which represents the amino-terminal 2152 amino acids of apo-B100. This is the first example of tissue-specific modification of a single mRNA nucleotide resulting in two different proteins from the same primary transcript.