Exon 10 skipping in ACAT1 caused by a novel c.949G>A mutation located at an exonic splice enhancer site.
Exon 10 skipping in ACAT1 caused by a novel c.949G>A mutation located at an exonic splice enhancer site.
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ACAT1 中的外显子 10 跳跃是由位于外显子剪接增强子位点的新型 c.949G>A 突变引起的。
作者：
Hiroki Otsuka;Hideo Sasai;M. Nakama;Y. Aoyama;Elsayed Abdelkreem;H. Ohnishi;V. Konstantopoulou;J. Sass;T. Fukao
β-酮硫解酶缺乏症，也称为线粒体乙酰乙酰辅酶A硫解酶（T2）缺乏症，是一种由乙酰辅酶A乙酰转移酶1（ACAT 1）基因突变引起的常染色体隐性遗传病。一名德国T2缺陷患者在11个月大时发生严重酮症酸中毒发作，被发现是先前报告的ACAT 1无效突变c.472A>G（p.N158D）和新突变c.949G>A（p.D317N）的复合杂合子。c.949G>A突变被怀疑引起异常剪接，因为它位于外显子剪接增强子序列内（c. 947 CTGACGC），是富含丝氨酸/精氨酸的剪接因子1的潜在结合位点。该序列中的突变c.951C>T导致外显子10跳跃。合成了一个小基因构建体，其中包括外显子9-截短的内含子9-外显子10-截短的内含子10-外显子11，该小基因的剪接显示，c.949G>A突变体构建体在一定比例的转录物中引起外显子10跳跃。此外，在外显子10的第一个核苷酸处额外的G替换为C（c.941G>C）消除了c.949G>A突变的影响。对c.949G>A突变体cDNA的瞬时表达分析显示，在突变的D317 N酶中没有残留的T2活性。因此，c.949G>A（D317 N）是一种致病性错义突变，并且减少了外显子剪接增强子的作用并导致外显子10跳跃。目前的研究表明，错义突变，甚至同义取代，可能会破坏酶的功能干扰剪接。
Beta-ketothiolase deficiency, also known as mitochondrial acetoacetyl-CoA thiolase (T2) deficiency, is an autosomal recessive disease caused by mutations in the acetyl‑CoA acetyltransferase 1 (ACAT1) gene. A German T2‑deficient patient that developed a severe ketoacidotic episode at the age of 11 months, was revealed to be a compound heterozygote of a previously reported null mutation, c.472A>G (p.N158D) and a novel mutation, c.949G>A (p.D317N), in ACAT1. The c.949G>A mutation was suspected to cause aberrant splicing as it is located within an exonic splicing enhancer sequence (c. 947CTGACGC) that is a potential binding site for serine/arginine‑rich splicing factor 1. A mutation in this sequence, c.951C>T, results in exon 10 skipping. A minigene construct was synthesized that included exon 9‑truncated intron 9‑exon 10‑truncated intron 10‑exon 11, and the splicing of this minigene revealed that the c.949G>A mutant construct caused exon 10 skipping in a proportion of the transcripts. Furthermore, additional substitution of G for C at the first nucleotide of exon 10 (c.941G>C) abolished the effect of the c.949G>A mutation. Transient expression analysis of the c.949G>A mutant cDNA revealed no residual T2 activity in the mutated D317N enzyme. Therefore, c.949G>A (D317N) is a pathogenic missense mutation, and diminishes the effect of an exonic splicing enhancer and causes exon 10 skipping. The present study demonstrates that a missense mutation, or even a synonymous substitution, may disrupt enzyme function by interference with splicing.
DOI：
10.1016/j.bbrc.2004.01.067
发表时间：
2004-03-05
影响因子：
3.1
作者：
Singh, NN;Androphy, EJ;Singh, RN
通讯作者：
Singh, RN