Possible Origin and Role of Nuclear Introns

转座因子能产生功能性内含子吗？该实验室最近证明，玉米转座元件，解离（ds）和复制的宿主序列的一个拷贝可以从原始转录物中精确拼接。实际上，Ds元素产生了一个内含子。因此，“内含子晚期”假说的工作模型已经创建，并将通过确定周围序列对Ds剪接的影响，确定8bp宿主复制对Ds剪接的序列要求，确定Ds剪接是否需要符合外显子/内含子边界的一致性，以及确定Ds-转内含子是否会给基因带来任何变化来测试和表征。内含子是由真核细胞（主要是真核细胞）的DNA转录而来的序列，通过剪接产生功能信息，但对于内含子是在进化史早期产生的，并通过提供“可移动的磁带”为基因的创造提供灵活性，还是仅仅是在进化史晚期随机插入基因的序列，没有任何功能目的，存在争议。将玉米中已知的转座因子描述为新产生的内含子，将为“内含子晚期”理论提供支持。＊＊＊

9420422 Hannah Can transposable elements give rise to functional introns? This laboratory has recently demonstrated that the maize transposable element, dissociation (ds) and one copy of the duplicated host sequence can be spliced precisely from the from the primary transcript. In effect, the Ds element has created an intron. A working model of the "intron-late" hypothesis has thus been created and will be tested and characterized by determining the effects of surrounding sequences on Ds splicing, determining the sequence requirements of the 8 bp host duplication on Ds splicing, determining whether fit to consensus of exon/intron borders is needed for Ds splicing and determining whether the Ds-turned intron confers any change on the gene. %%% A controversy exists as to whether introns, sequences which although transcribed from the DNA of (primarily) eukaryotic cells are spliced out to create a functional message, were created early in evolutionary history and served the purpose of providing flexibility in the creation of genes by providing "movable cassettes" or whether they are simply sequences which have been randomly inserted into genes late in evolutionary history and serve no functional purpose. The characterization of a known and well described transposable element in corn as a newly created intron would lend support to the "intron-late" theory. ***