Basu Malay Kumar, Makalowski Wojciech, Rogozin Igor B, Koonin Eugene V
National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA.
Biol Direct. 2008 May 14;3:19. doi: 10.1186/1745-6150-3-19.
We report that the positions of minor, U12 introns are conserved in orthologous genes from human and Arabidopsis to an even greater extent than the positions of the major, U2 introns. The U12 introns, especially, conserved ones are concentrated in 5'-portions of plant and animal genes, where the U12 to U2 conversions occurs preferentially in the 3'-portions of genes. These results are compatible with the hypothesis that the high level of conservation of U12 intron positions and their persistence in genomes despite the unidirectional U12 to U2 conversion are explained by the role of the slowly excised U12 introns in down-regulation of gene expression.
我们报告称，与主要的U2内含子相比，次要的U12内含子在人类和拟南芥直系同源基因中的位置保守程度更高。特别是U12内含子，保守的U12内含子集中在植物和动物基因的5'端，而U12向U2的转换优先发生在基因的3'端。这些结果与以下假设相符：尽管存在U12向U2的单向转换，但U12内含子位置的高度保守性及其在基因组中的持续存在可以通过缓慢切除的U12内含子在基因表达下调中的作用来解释。
