Evolutionary fates and origins of U12-type introns
Evolutionary fates and origins of U12-type introns
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DOI：
10.1016/s1097-2765(00)80292-0
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发表时间：
1998-12-01
期刊：
影响因子：
16
通讯作者：
Sharp, PA
中科院分区：
文献类型：
--
作者：
Burge, CB;Padgett, RA;Sharp, PA
在真核生物细胞核中，u2型和u12型内含子由不同的剪接体剪接。设计了一种基于剪接位点序列特性区分这两种类型内含子的分类方法，并在现有基因组序列中鉴定了56种不同的含有u12型内含子的基因。u12型内含子在各种真核生物分类群中出现的频率一直很低，但几乎可以肯定，在秀丽隐杆线虫中已经丢失了。与现有同源序列的比较表明，在RT-AG和GT-AG的末端之间存在U12内含子的亚型转换，以及内含子从U12型向u2型的转换，并为裂变/融合模型提供了证据，在该模型中，两种剪接系统在不同的谱系中进化，并融合在真核祖细胞中。
U2-type and U12-type introns are spliced by distinct spliceosomes in eukaryotic nuclei. A classification method was devised to distinguish these two types of introns based on splice site sequence properties and was used to identify 56 different genes containing U12-type introns In available genomic sequences. U12-type introns occur with a consistently low frequency in diverse eukaryotic taxa but have almost certainly been lost from C. elegans. Comparisons with available homologous sequences demonstrate subtype switching of U12 introns between termini of RT-AG and GT-AG as well as conversion of introns from U12-type to U2-type and provide evidence for a fission/fusion model in which the two splicing systems evolved in separate lineages that were fused in a eukaryotic progenitor.