Exons as microgenes?
Exons as microgenes?
复制标题
外显子作为微基因？
DOI：
10.1126/science.1523407
复制
发表时间：
1992
期刊：
影响因子：
56.9
通讯作者：
J. Knowles
中科院分区：
文献类型：
--
作者：
H. Seidel;D. Pompliano;J. Knowles
非蛋白质编码的核糖体RNA和转运RNA基因中不存在J d连接序列，它们具有完全不同的剪接机制。蛋白质编码基因中剪接位点共有序列的起源是什么？简单的解释是，序列一致性只是一个历史偶然事件，并没有携带关于其进化起源的信息。然而，考虑到古老的RNA剪接机制的存在，蛋白质编码基因特有的剪接共有序列的进化似乎不太可能是偶然的，更可能反映了这些序列的早期功能作用。Tet-rahymena基因中内含子的位置既解释了真核外显子和内含子3 '末端的起源，也表明外显子可能曾经是”微基因”，最初以琥珀终止，编码相对较短的寡肽，自发组装成活性蛋白。其论点如下：从原始RNA的不同片段开始，蛋白质合成的起始（在i）和终止（在t）将产生寡肽文库（a、B、c等），这些寡肽的某些组合将自发地联合收割机结合形成具有催化活性的多链蛋白质组装体（见图）。这种蛋白质片段聚集在一起产生催化活性单元的组装体是众所周知的（6）。通过使用它们共同的琥珀末端（t）作为剪接的识别元件（7），这些微基因的剪接可以使适当的微基因更接近，从而提高所有有助于特定催化活性的片段的连锁遗传的机会。这个概念是; t
\J d junction sequences do not occur in the non-protein-encoding ribosomal RNA and transfer RNA genes, which have quite different splicing mechanisms. What is the origin of the splice-site consensus sequences in protein-encoding genes? The trivial explanation is that the sequence consensus is simply a historical accident and carries no information about its evolutionary origin. Given the existence ofancient RNA splicing mechanisms, however, the evolution of a splicing consensus sequence peculiar to protein-encoding genes seems unlikely to have been accidental and more likely reflects an early functional role of these sequences. The location of the introns in the Tet-rahymena mutase gene both explains the origin of the 3'-termini of eukaryotic exons and introns and suggests the possibility that exons were once" microgenes," originally terminating with amber and encoding relatively short oligopeptides that assembled spontaneously into active protein. The argument runs as follows: from various segments of primordial RNA, initiation of protein synthesis (at i) and termination (at t) would produce a library of oligopeptides (a, b, c, and so forth), some combinations of which would spontaneously combine to form multichain protein assemblies having catalytic activity (see figure). Such assemblies, in which protein fragments come together to generate a catalytically active unit, are well known (6). Splicing of these microgenes by using their common amber termini (t) as a recognition element for splicing (7) could then bring the appropriate microgenes closer together, thereby improving the chances for the linked inheritance of all the fragments that contribute to a particular catalytic activity. This notion is; t
双域珠蛋白基因中“桥”内含子的起源。
DOI：
10.1073/pnas.88.15.6672
发表时间：
1991
影响因子：
11.1
作者：
Naito,Y;Riggs,CK;Vandergon,TL;Riggs,AF
通讯作者：
Riggs,AF