TCIRG1-dependent recessive osteopetrosis: mutation analysis, functional identification of the splicing defects, and in vitro rescue by U1 snRNA
- PMID: 15300850
- DOI: 10.1002/humu.20076
TCIRG1-dependent recessive osteopetrosis: mutation analysis, functional identification of the splicing defects, and in vitro rescue by U1 snRNA
Abstract
Human malignant infantile osteopetrosis (arOP) is a genetically heterogeneous autosomal recessive disorder of bone metabolism. The TCIRG1 gene, encoding the a3 subunit of the vacuolar proton pump, which mediates the acidification of the bone/osteoclast interface, is responsible for more than one-half of the arOP patients. We performed genetic analysis of TCIRG1 in 55 arOP patients including 25 new cases and identified nine novel mutations. The two most frequent mutations, c.1674-1G>A (aberrant splicing: r.1674_1884del) and c.2005C>T (protein variation: p.Arg669X), found in 17 and 16 alleles, respectively, constituted 30% of all TCIRG1 abnormalities. They both originated in Northern Europe, p.Arg669X quite recently from West Flanders, Belgium. As substitutions in splicing regulatory sequences represented a large portion (40%; 44 alleles) of the TCIRG1 variations, we developed a functional splicing assay to distinguish between polymorphic variants and disease-causing mutations. Three intronic nucleotide substitutions flanking the splice sites (c.117+4A>T; c.1673+5G>A; and c.504-8G>A) were studied using hybrid minigenes and an abnormal processing of the transcripts was demonstrated in all cases. Cotransfection experiments with complementary U1 snRNAs performed in c.117+4A>T and c.1673+5G>A mutations showed that only in the first case was the defect at the 5' splice site corrected, indicating that mutations near the invariant GT donor sites are mechanistically different. These findings indicate the feasibility of the hybrid minigene approach to detect splicing defects, particularly in patients in whom the RNA is not available. In addition, the present results suggest that modified U1 snRNAs may represent a new therapeutic strategy for arOP patients with a U1 snRNP-dependent splicing defect.
Copyright 2004 Wiley-Liss, Inc.
Similar articles
-
Novel c.G630A TCIRG1 mutation causes aberrant splicing resulting in an unusually mild form of autosomal recessive osteopetrosis.J Cell Biochem. 2019 Oct;120(10):17180-17193. doi: 10.1002/jcb.28979. Epub 2019 May 20. J Cell Biochem. 2019. PMID: 31111556
-
The mutational spectrum of human malignant autosomal recessive osteopetrosis.Hum Mol Genet. 2001 Aug 15;10(17):1767-73. doi: 10.1093/hmg/10.17.1767. Hum Mol Genet. 2001. PMID: 11532986
-
As little as needed: the extraordinary case of a mild recessive osteopetrosis owing to a novel splicing hypomorphic mutation in the TCIRG1 gene.J Bone Miner Res. 2014 Jul;29(7):1646-50. doi: 10.1002/jbmr.2203. J Bone Miner Res. 2014. PMID: 24535816 Free PMC article.
-
Rare gross deletion in T-cell immune regulator-1 gene in Iranian family with infantile malignant osteopetrosis.Saudi Med J. 2008 Oct;29(10):1494-6. Saudi Med J. 2008. PMID: 18946580 Review.
-
Development of Engineered-U1 snRNA Therapies: Current Status.Int J Mol Sci. 2023 Sep 27;24(19):14617. doi: 10.3390/ijms241914617. Int J Mol Sci. 2023. PMID: 37834063 Free PMC article. Review.
Cited by
-
An Exon-Specific Small Nuclear U1 RNA (ExSpeU1) Improves Hepatic OTC Expression in a Splicing-Defective spf/ash Mouse Model of Ornithine Transcarbamylase Deficiency.Int J Mol Sci. 2020 Nov 19;21(22):8735. doi: 10.3390/ijms21228735. Int J Mol Sci. 2020. PMID: 33228018 Free PMC article.
-
Osteopetrosis: genetics, treatment and new insights into osteoclast function.Nat Rev Endocrinol. 2013 Sep;9(9):522-36. doi: 10.1038/nrendo.2013.137. Epub 2013 Jul 23. Nat Rev Endocrinol. 2013. PMID: 23877423 Review.
-
V-ATPases and osteoclasts: ambiguous future of V-ATPases inhibitors in osteoporosis.Theranostics. 2018 Oct 26;8(19):5379-5399. doi: 10.7150/thno.28391. eCollection 2018. Theranostics. 2018. PMID: 30555553 Free PMC article. Review.
-
Structural and functional understanding of disease-associated mutations in V-ATPase subunit a1 and other isoforms.Front Mol Neurosci. 2023 Jul 3;16:1135015. doi: 10.3389/fnmol.2023.1135015. eCollection 2023. Front Mol Neurosci. 2023. PMID: 37465367 Free PMC article. Review.
-
Fetal liver cells transplanted in utero rescue the osteopetrotic phenotype in the oc/oc mouse.Am J Pathol. 2009 Mar;174(3):727-35. doi: 10.2353/ajpath.2009.080688. Epub 2009 Feb 13. Am J Pathol. 2009. PMID: 19218349 Free PMC article.
Publication types
MeSH terms
Substances
Associated data
- Actions
- Actions
- Actions
- Actions
LinkOut - more resources
Full Text Sources
Medical
Molecular Biology Databases
Research Materials
Miscellaneous