APOLIPOPROTEIN B-48 IS THE PRODUCT OF A MESSENGER-RNA WITH AN ORGAN-SPECIFIC IN-FRAME STOP CODON
APOLIPOPROTEIN B-48 IS THE PRODUCT OF A MESSENGER-RNA WITH AN ORGAN-SPECIFIC IN-FRAME STOP CODON
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DOI：
10.1126/science.3659919
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发表时间：
1987-10-16
期刊：
影响因子：
56.9
通讯作者：
CHAN, L
中科院分区：
文献类型：
--
作者：
CHEN, SH;HABIB, G;CHAN, L
人载脂蛋白（apo）B - 48的一级结构已被推导出来，并且通过DNA过量杂交、胰蛋白酶肽段测序、克隆的互补DNA以及肠道信使RNA（mRNA）的综合研究表明，它是一种肠道mRNA的产物，该mRNA具有一个符合读码框的UAA终止密码子，这是由于apoB - 100 mRNA中编码谷氨酰胺2153的密码子CAA发生了C到U的改变。从乳糜性腹水液中纯化的apoB - 48的羧基末端异亮氨酸2152显然已从初始翻译产物上被切割下来，使得蛋氨酸2151成为新的羧基末端。这些数据表明，大约85%的肠道mRNA在终止密码子下游约0.1到1.0千碱基处终止。另外约15%的mRNA长度与肝脏apoB - 100 mRNA相似，尽管它们具有相同的符合读码框的终止密码子。在mRNA中引入器官特异性的终止密码子似乎是前所未有的，并且可能对隐蔽的多聚腺苷酸化信号识别和RNA加工具有影响。
The primary structure of human apolipoprotein (apo) B-48 has been deduced and shown by a combination of DNA excess hybridization, sequencing of tryptic peptides,cloned complementary DNAs, and intestinal messenger RNAs (mRNAs) to be the product of an intestinal mRNA with an in-frame UAA stop codon resulting from a C to U change in the codon CAA encoding Gln2153 in apoB-100 mRNA. The carboxyl-terminal Ile2152 of apoB-48 purified from chylous ascites fluid has apparently been cleaved from the initial translation product, leaving Met2151 as the new carboxyl-terminus. These data indicate that .apprx. 85% of the intestinal mRNAs terminate within .apprx. 0.1 to 1.0 kilobase downstream from the stop codon. The other .apprx.15% have lengths similar to hepatic apoB-100 mRNA even though they have the same in-frame stop codon. The organ-specific introduction of a stop codon to a mRNA appears unprecedented and might have implications for cryptic polyadenylation signal recognition and RNA processing.