Detailed secondary structure models of invertebrate 7SK RNAs

The 7SK RNA is a small nuclear RNA that is involved in the regulation of Pol-II transcription. It is very well conserved in vertebrates, but shows extensive variations in both sequence and structure across invertebrates. A systematic homology search extended the collection of 7SK genes in both Arthropods and Lophotrochozoa making use of the large number of recently published invertebrate genomes. The extended data set made it possible to infer complete consensus structures for invertebrate 7SK RNAs. These show that not only the well-conserved 5′- and 3′- domains but all the interior Stem A domain is universally conserved. In contrast, Stem B region exhibits substantial structural variation and does not adhere to a common structural model beyond phylum level.

7SK核糖核酸（7SK RNA）是一类参与RNA聚合酶II（Pol-II）转录调控的小核RNA（small nuclear RNA）。该RNA在脊椎动物中高度保守，但在无脊椎动物类群间的序列与结构均存在广泛差异。本研究利用近期发表的大量无脊椎动物基因组数据，通过系统性同源性搜索，扩充了节肢动物门（Arthropods）与冠轮动物总门（Lophotrochozoa）中7SK基因的收录范围。扩充后的数据集得以完成对无脊椎动物7SK RNA完整共识结构的推断。分析结果显示，不仅高度保守的5'端与3'端结构域，就连内部的茎区A（Stem A）均全域保守。与之相反，茎区B（Stem B）区域呈现显著的结构变异，在门级分类阶元以上的类群中无法适配统一的结构模型。