Jaworski C J, Piatigorsky J
Laboratory of Molecular and Developmental Biology, National Eye Institute, Bethesda, Maryland 20892.
Nature. 1989 Feb 23;337(6209):752-4. doi: 10.1038/337752a0.
The frequent correspondence of exons to structural or functional domains in proteins has suggested that many proteins have evolved by modular assembly. This idea is supported by examples of apparent exon duplication and by shared domains among both alternatively spliced and completely separate genes. During this process it is probable that some combinations of exons would not prove advantageous and would therefore be lost. Here we report that within the active single-copy human gene for alpha A-crystallin there is a 'pseudo-exon' in the early stages of being extinguished, perhaps the result of a failed experiment in the evolution of this specialized, lens-specific protein.
外显子与蛋白质的结构或功能域频繁对应，这表明许多蛋白质是通过模块化组装进化而来的。明显的外显子重复实例以及可变剪接基因和完全独立基因之间共享的结构域都支持了这一观点。在这个过程中，一些外显子组合可能不会被证明具有优势，因此会丢失。我们在此报告，在有活性的单拷贝人类αA-晶体蛋白基因中，有一个处于被淘汰早期阶段的“假外显子”，这可能是这种特殊的、晶状体特异性蛋白质进化过程中一次失败实验的结果。
