Jackson Scott, Cannone Jamie, Lee Jung, Gutell Robin, Woodson Sarah
Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20497-2021, USA.
J Mol Biol. 2002 Oct 11;323(1):35-52. doi: 10.1016/s0022-2836(02)00895-1.
More than 1200 introns have been documented at over 150 unique sites in the small and large subunit ribosomal RNA genes (as of February 2002). Nearly all of these introns are assigned to one of four main types: group I, group II, archaeal and spliceosomal. This sequence information has been organized into a relational database that is accessible through the Comparative RNA Web Site (http://www.rna.icmb.utexas.edu/) While the rRNA introns are distributed across the entire tree of life, the majority of introns occur within a few phylogenetic groups. We analyzed the distributions of rRNA introns within the three-dimensional structures of the 30S and 50S ribosomes. Most sites in rRNA genes that contain introns contain only one type of intron. While the intron insertion sites occur at many different coordinates, the majority are clustered near conserved residues that form tRNA binding sites and the subunit interface. Contrary to our expectations, many of these positions are not accessible to solvent in the mature ribosome. The correlation between the frequency of intron insertions and proximity of the insertion site to functionally important residues suggests an association between intron evolution and rRNA function.
截至2002年2月，在小亚基和大亚基核糖体RNA基因的150多个独特位点已记录了1200多个内含子。几乎所有这些内含子都被归为四种主要类型之一：I类、II类、古细菌型和剪接体型。这些序列信息已被整理到一个关系数据库中，可通过比较RNA网站（http://www.rna.icmb.utexas.edu/）访问。虽然rRNA内含子分布在整个生命树中，但大多数内含子出现在少数几个系统发育组内。我们分析了30S和50S核糖体三维结构内rRNA内含子的分布。rRNA基因中大多数含有内含子的位点只包含一种类型的内含子。虽然内含子插入位点出现在许多不同的坐标处，但大多数聚集在形成tRNA结合位点和亚基界面的保守残基附近。与我们的预期相反，在成熟核糖体中，这些位置中的许多对溶剂不可及。内含子插入频率与插入位点与功能重要残基的接近程度之间的相关性表明内含子进化与rRNA功能之间存在关联。
