Exon 10 skipping in ACAT1 caused by a novel c.949G>A mutation located at an exonic splice enhancer site
- Beta-ketothiolase deficiency, also known as mitochondrial acetoacetyl-CoA thiolase (T2) deficiency, is an autosomal recessive disease caused by mutations in the acetylCoA acetyltransferase 1 (ACAT1) gene. A German T2deficient 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/argininerich splicing factor 1. A mutation in this sequence, c.951C>T, results in exon 10 skipping. A minigene construct was synthesized that included exon 9truncated intron 9exon 10truncated intron 10exon 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.
Document Type: | Article |
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Language: | English |
Author: | Hiroki Otsuka, Hideo Sasai, Mina Nakama, Yuka Aoyama, Elsayed Abdelkreem, Hidenori Ohnishi, Vassiliki Konstantopoulou, Jörn Oliver Sass, Toshiyuki Fukao |
Parent Title (English): | Molecular Medicine Reports |
Volume: | 14 |
Issue: | 5 |
First Page: | 4906 |
Last Page: | 4910 |
ISSN: | 1791-2997 |
DOI: | https://doi.org/10.3892/mmr.2016.5819 |
PMID: | https://pubmed.ncbi.nlm.nih.gov/27748876 |
Publisher: | Spandidos |
Date of first publication: | 2016/10/10 |
Departments, institutes and facilities: | Fachbereich Angewandte Naturwissenschaften |
Institut für funktionale Gen-Analytik (IFGA) | |
Dewey Decimal Classification (DDC): | 6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit |
Entry in this database: | 2017/01/25 |