Exon skipping in IVD RNA processing in isovaleric acidemia caused by point mutations in the coding region of the IVD gene.
Exon skipping in IVD RNA processing in isovaleric acidemia caused by point mutations in the coding region of the IVD gene.
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DOI：
10.1086/302751
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发表时间：
2000-02
影响因子：
9.8
通讯作者：
J. Vockley;P. Rogan;B. Anderson;J. Willard;R. S. Seelan;David C. Smith;Wanguo Liu
中科院分区：
文献类型：
--
作者：
J. Vockley;P. Rogan;B. Anderson;J. Willard;R. S. Seelan;David C. Smith;Wanguo Liu
异戊酸血症（IVA）是一种由异戊酸辅酶a脱氢酶（IVD）缺乏引起的隐性疾病。我们在其他地方报道了IVA患者成纤维细胞中IVD基因的9个点突变，这导致IVD蛋白加工和活性异常。在本报告中，我们描述了在7例IVA患者中发现的8个IVD基因突变，这些突变导致IVD RNA剪接异常。编码区的四个突变导致患者成纤维细胞中mRNA物种剪接异常。其中三种是改变氨基酸的点突变，而一种是单碱基插入，导致mRNA的阅读框发生移位。其中两个编码突变加强了天然剪接接点附近已有的隐剪接受体，并明显干扰外显子识别，导致外显子跳变。这种错误剪接的机制尚未在其他地方报道。另外四个突变改变了IVD基因中保守的gt或ag二核苷酸剪接位点。通过将这些突变转染到Cos-7细胞系模型剪接系统中，证实了外显子跳变和隐剪接。通过个体信息分析预测，一些突变会使邻近的供体或受体位点失活或显著减弱。在这些患者中发现的高频率剪接突变是不寻常的，正如外显子中发现的与错义突变相关的错误剪接一样。这些结果可能有助于更好地理解IVA的表型复杂性，并为体内定义内含子/外显子边界的重要因素提供见解。
Isovaleric acidemia (IVA) is a recessive disorder caused by a deficiency of isovaleryl-CoA dehydrogenase (IVD). We have reported elsewhere nine point mutations in the IVD gene in fibroblasts of patients with IVA, which lead to abnormalities in IVD protein processing and activity. In this report, we describe eight IVD gene mutations identified in seven IVA patients that result in abnormal splicing of IVD RNA. Four mutations in the coding region lead to aberrantly spliced mRNA species in patient fibroblasts. Three of these are amino acid altering point mutations, whereas one is a single-base insertion that leads to a shift in the reading frame of the mRNA. Two of the coding mutations strengthen pre-existing cryptic splice acceptors adjacent to the natural splice junctions and apparently interfere with exon recognition, resulting in exon skipping. This mechanism for missplicing has not been reported elsewhere. Four other mutations alter either the conserved gt or ag dinucleotide splice sites in the IVD gene. Exon skipping and cryptic splicing were confirmed by transfection of these mutations into a Cos-7 cell line model splicing system. Several of the mutations were predicted by individual information analysis to inactivate or significantly weaken adjacent donor or acceptor sites. The high frequency of splicing mutations identified in these patients is unusual, as is the finding of missplicing associated with missense mutations in exons. These results may lead to a better understanding of the phenotypic complexity of IVA, as well as provide insight into those factors important in defining intron/exon boundaries in vivo.