Kiss T, Jakab G, Antal M, Pálfi Z, Hegyi H, Kis M, Solymosy F
Institute of Plant Physiology, Hungarian Academy of Sciences, Szeged.
Nucleic Acids Res. 1988 Jun 24;16(12):5407-26. doi: 10.1093/nar/16.12.5407.
U4 RNA, which is known to play an indispensable role in pre-mRNA splicing, is present in plant nuclei, has a canonical m3 2,2,7 G cap at its 5' end and is associated with U6 RNA in snRNP particles. It occurs in broad bean in the form of a number of sequence variants. Two of these were sequenced: U4A RNA is 154 and U4B RNA is 152 nucleotides long. Sequence similarity of broad bean U4B RNA is 94 per cent to broad bean U4A RNA, 65 per cent to rat U4A RNA, 61 per cent to Drosophila U4A RNA and 50 per cent to snR14, the U4 RNA equivalent of the yeast Saccharomyces cerevisiae. Sequence conservation is much more pronounced in the 5' half of the molecule than in its 3' half. The secondary structure of both variants of broad bean U4 RNA perfectly fits with that of all other U4 RNAs sequenced so far. Nucleotide changes between broad bean U4A and U4B RNAs are restricted to molecular regions that affect the thermodynamic stability of these molecules. A model is proposed for the base pairing interaction of broad bean U4 RNA with broad bean U6 RNA. This is the first report on the structure of a plant U4 RNA.
U4 RNA在mRNA前体剪接中发挥着不可或缺的作用，存在于植物细胞核中，其5'端有一个典型的m3 2,2,7 G帽结构，并与核内小核糖核蛋白颗粒中的U6 RNA相关联。它在蚕豆中以多种序列变体的形式存在。其中两种已被测序：U4A RNA长154个核苷酸，U4B RNA长152个核苷酸。蚕豆U4B RNA与蚕豆U4A RNA的序列相似性为94%，与大鼠U4A RNA的序列相似性为65%，与果蝇U4A RNA的序列相似性为61%，与酿酒酵母的U4 RNA等效物snR14的序列相似性为50%。分子的5'端比3'端的序列保守性更为明显。蚕豆U4 RNA的两种变体的二级结构与迄今为止测序的所有其他U4 RNA的二级结构完全吻合。蚕豆U4A和U4B RNA之间的核苷酸变化仅限于影响这些分子热力学稳定性的分子区域。本文提出了蚕豆U4 RNA与蚕豆U6 RNA碱基配对相互作用的模型。这是关于植物U4 RNA结构的首次报道。
