Aberrantly spliced mRNAs of the 3-hydroxy-3-methylglutaryl coenzyme A lyase (HL) gene with a donor splice-site point mutation produce hereditary HL deficiency
Author
Buesa, Carlos
Pié, Juan
Barceló, Ana
Casals i Farré, Núria
Mascaró, Cristina
Casale, César H.
Haro, Diego
Duran, Marinus
Smeitink, Jan A. M.
Hegardt, Fausto G.
Publication date
1996-11ISSN
0022-2275
Abstract
A novel point mutation in the 3-hydroxy-3methyl-glutaryl coenzyme A lyase gene was found in a Turkish patient with homozygous 3-hydroxy-3-methylglutaric acidemia. Amplification by RT-PCR of the mRNA using a six different pairs of oligonucleotides produced no differences in four of the fragments amplified with respect to the control, but generated two fragments of different size. One was representative of a deletion of 126 bp and the other of an insertion of 78 bp. These abnormal mRNAs resulted from a G–>C transversion at the nucleotide +1 of an intron, which changed the invariant GT dinucleotide of the 5' donor splice site. This was associated with the occurrence of an alternative splicing, which led to the skipping of the whole exon of 126 bp, and also with the activation of one cryptic donor splice site in the same intron. These aberrant spliced mRNAs are predicted to encode two abnormal HMG-CoA lyase proteins: the first results in a protein with an internal deletion of 42 amino acids, whose enzyme activity is largely abolished, as the catalytic site was completely removed; the second contains 17 missense amino acids that precede a stop codon. Northern blot analysis showed that the overall content of these aberrantly spliced mRNAs in proband fibroblasts was the same as that found in control fibroblasts. However, hardly any transcript was observed corresponding to the inserted mutated mRNA when it was examined by a specific probe. To quantify the relative proportion of the two mRNAs, a quantitative RT-PCR (the DNA-mimic PCR reaction) was carried out. Results show that the proportion of the inserted mRNAs with respect to the deleted mRNA is only 1.2%. The father, mother, and two brothers of the proband were heterozygous in the G–>C mutation in the +1 nucleotide of the intron considered, while the two alleles of another brother were free of the mutation.
Document Type
Article
Document version
Published version
Language
English
Subject (CDU)
61 - Medical sciences
Keywords
Nucleòtids
RNA
Aminoàcids
Enzims
ADN
Nucleótidos
ARN
Aminoácidos
Enzimas
ADN
Nucleotides
RNA
Amino acids
Enzymes
DNA
Pages
13
Publisher
American Society for Biochemistry and Molecular Biology
Collection
37;11
Is part of
Journal of Lipid Research
Citation
Buesa, Carlos; Pié, Juan; Barceló, Ana [et al.]. Aberrantly spliced mRNAs of the 3-hydroxy-3-methylglutaryl coenzyme A lyase (HL) gene with a donor splice-site point mutation produce hereditary HL deficiency. Journal of Lipid Research, 1996, 37(11), p. 2420-2432. Disponible en: <https://www.sciencedirect.com/science/article/pii/S0022227520374903?via%3Dihub>. Fecha de acceso: 4 may. 2021. DOI: 10.1016/S0022-2275(20)37490-3
This item appears in the following Collection(s)
- Ciències de la Salut [725]
Rights
Under a Creative Commons license. This is an Open Access article under theCC BY license.
Except where otherwise noted, this item's license is described as https://creativecommons.org/licenses/by/4.0/