Post-transcriptional modification of spliceosomal RNAs is normal in SMN-deficient cells
Post-transcriptional modification of spliceosomal RNAs is normal in SMN-deficient cells
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DOI：
10.1261/rna.030106.111
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发表时间：
2012-01-01
期刊：
影响因子：
4.5
通讯作者：
Bordonne, Remy
中科院分区：
文献类型：
--
作者：
Deryusheva, Svetlana;Choleza, Maria;Bordonne, Remy
运动神经元存活蛋白（survivalofmotorneuron，SMN）在剪接体snRNP的生物发生中起重要作用，是维持核Cajalbody（CB）完整性所必需的因子之一。CB富含小CB特异性（sca）RNA，其引导snRNA中假尿苷化和2 '-O-甲基化残基的形成。由于SMN缺陷细胞缺乏典型的CB，我们询问这些细胞中主要和次要snRNA的内部残基的修饰是否有缺陷。我们绘制了主要U2和次要U4 atac和U12 snRNAs中的修饰核苷酸。使用放射性和荧光引物延伸的方法，我们发现，修改的主要和次要剪接体snRNAs是正常的SMN缺陷细胞。我们的实验还揭示了以前未检测到的假尿苷在位置60在人类U2和2 '-O-甲基化的A1，A2，和G19在人类U4 atac。这些结果证实，并扩展到次要snRNA，先前的实验表明scaRNP可以在不存在典型CB的情况下发挥作用。此外，他们表明SMN缺陷细胞中的差异剪接缺陷不是由于主要或次要snRNA的转录后修饰失败。
The survival of motor neuron (SMN) protein plays an important role in the biogenesis of spliceosomal snRNPs and is one factor required for the integrity of nuclear Cajal bodies (CBs). CBs are enriched in small CB-specific (sca) RNAs, which guide the formation of pseudouridylated and 2'-O-methylated residues in the snRNAs. Because SMN-deficient cells lack typical CBs, we asked whether the modification of internal residues of major and minor snRNAs is defective in these cells. We mapped modified nucleotides in the major U2 and the minor U4atac and U12 snRNAs. Using both radioactive and fluorescent primer extension approaches, we found that modification of major and minor spliceosomal snRNAs is normal in SMN-deficient cells. Our experiments also revealed a previously undetected pseudouridine at position 60 in human U2 and 2'-O-methylation of A1, A2, and G19 in human U4atac. These results confirm, and extend to minor snRNAs, previous experiments showing that scaRNPs can function in the absence of typical CBs. Furthermore, they show that the differential splicing defects in SMN-deficient cells are not due to failure of post-transcriptional modification of either major or minor snRNAs.