拟南芥U59snoRNA基因簇的结构与功能研究

Study on the Structure and Function of U59 snoRNA Gene Cluster from A.thaliana

在拟南芥 (Arabidopsisthaliana)中发现和鉴定了具有两个反义序列的snoRNA组成的一个基因簇 .该基因簇由两个相同的snoRNA基因组成 .位于boxD′上游的反义序列与人U59snoRNA基因的反义序列相同 ,因此命名为拟南芥U59a和U59b .位于boxD上游的反义序列在所有哺乳动物和酵母snoRNA基因的反义序列中未找到同源拷贝 .经低浓度的dNTP逆转录检验证实此反义序列并不指导拟南芥 2 5SrRNAGl84 5位点 2′ o 核糖甲基化 .这些结果表明 :拟南芥U59a和U59bsnoRNA基因与动物U59snoRNA在基因结构、组织和功能上有较大的差异 .拟南芥U59snoRNA基因簇的发现为进一步研究植物rRNA的加工和修饰、植物snoRNA基因的组织与表达多样性以及两个反义序列snoRNA基因的起源提供了一个良好的研究体系 .

U59 snoRNA gene cluster, consisted of two same snoRNA genes possessing two antisense elements each, was identified and characterized from A thaliana.The antisense element located upstream of box D′is identical to that of U59 snoRNA identified from human, so, they were termed as A thaliana U59a and U59b snoRNA respectively. The antisense element located in the upstream of box D is different from all of those of snoRNA identified from mammlian and yeast genome. It was verified that the antisense element located upstream of box D dos not guide A thaliana 25S rRNA G1845 2′-o-ribose methylation revealed by lower concentrition dNTP reverse transcription analysis. The results showed the important difference between A thaliana U59 snoRNA and human U59 snoRNA, suggesting A thaliana U59 snoRNA gene cluster as a good system for further studying diversities of plant snoRNA gene organization and expression, and the origin of snoRNA genes.