Foci of trinucleotide repeat transcripts in nuclei of myotonic dystrophy cells and tissues.

Taneja, Krishan; McCurrach, Mila E.; Schalling, Martin; Housman, David E.; Singer, Robert H.

doi:10.1083/jcb.128.6.995

Cited by 549 publications

(457 citation statements)

References 27 publications

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“…1 ). Unlike the wild-type transcript, mutant DMPK mRNA forms nuclear aggregates 3,4 and is thought to trigger dominant effects by aberrant interactions with or altered activity of RNA splicing factors, principally members of the muscleblind-like (MBNL) family (such as MBNL1) and the CUG-BP and ETR3-like factor (CELF) family (such as CUG-BP1), leading to abnormal splicing of specific RNAs such as chloride channel (Clcn1), insulin Correspondence should be addressed to M.S.M. (mahadevan@virginia.edu).…”

Section: Introductionmentioning

confidence: 99%

“…22 ). The RNA foci in DM2 contain only the (CCUG) n RNA 23 , whereas in DM1 the entire processed mutant DMPK mRNA is present 3,4 , suggesting that the context in which the (CUG) repeats reside (that is, the DMPK 3′ UTR) is important with respect to induction of CUG-BP1. Although speculative, this may prove to be important in understanding differences between DM1 and DM2, such as congenital myotonic dystrophy, which is seen only in DM1.…”

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confidence: 99%

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Reversible model of RNA toxicity and cardiac conduction defects in myotonic dystrophy

et al. 2006

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Myotonic dystrophy (DM1), the most common muscular dystrophy in adults, is caused by an expanded (CTG) n tract in the 3′ UTR of the gene encoding myotonic dystrophy protein kinase (DMPK) 1 , which results in nuclear entrapment of the 'toxic' mutant RNA and interacting RNAbinding proteins (such as MBNL1) in ribonuclear inclusions 2 . It is unclear if therapy aimed at eliminating the toxin would be beneficial. To address this, we generated transgenic mice expressing the DMPK 3′ UTR as part of an inducible RNA transcript encoding green fluorescent protein (GFP). We were surprised to find that mice overexpressing a normal DMPK 3′ UTR mRNA reproduced cardinal features of myotonic dystrophy, including myotonia, cardiac conduction abnormalities, histopathology and RNA splicing defects in the absence of detectable nuclear inclusions. However, we observed increased levels of CUG-binding protein (CUG-BP1) in skeletal muscle, as seen in individuals with DM1. Notably, these effects were reversible in both mature skeletal and cardiac muscles by silencing transgene expression. These results represent the first in vivo proof of principle for a therapeutic strategy for treatment of myotonic dystrophy by ablating or silencing expression of the toxic RNA molecules.Common features of adult-onset DM1 include myotonia, progressive skeletal muscle loss, cardiac conduction defects, smooth muscle dysfunction, cataracts and insulin resistance 2 . The normal number of CTG repeats (n = 5 to ~30) is higher (n = 50 to >3,000) in individuals with DM1 (ref. 1 ). Unlike the wild-type transcript, mutant DMPK mRNA forms nuclear aggregates 3,4 and is thought to trigger dominant effects by aberrant interactions with or altered activity of RNA splicing factors, principally members of the muscleblind-like (MBNL) family (such as MBNL1) and the CUG-BP and ETR3-like factor (CELF) family (such as CUG-BP1), leading to abnormal splicing of specific RNAs such as chloride channel (Clcn1), insulin Correspondence should be addressed to M.S.M. (mahadevan@virginia.edu). 4 These authors contributed equally to this work. AUTHOR CONTRIBUTIONSM.S.M., R.S.Y., Q.Y., C.D.F.-M., T.D.B. and L.H.P. performed experimental work and data analysis. S.B. generated the transgene constructs. M.S.M. was responsible for conceptual design and execution. COMPETING INTERESTS STATEMENTThe authors declare that they have no competing financial interests. One potential therapeutic approach in DM1 is to get rid of the toxic RNA from cells. However, it is unclear if this will alleviate the effects of the disease. We used the tetracycline (Tet) inducible system with the reverse tetracycline transactivator (rtTA) to generate double transgenic mice harboring (i) a Tet-responsive, DMPK promoter 10,11 -driven transgene (named GFP-DMPK 3′ UTR) expressing the DMPK 3′ UTR mRNA as part of a GFP transcript, and (ii) a constitutively expressed rtTA transgene (Fig. 1a) Fig. 1). Notably, RNA blots of skeletal muscle RNA showed two major species due to alternative use of polyadenylation signal...

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Reversible model of RNA toxicity and cardiac conduction defects in myotonic dystrophy

et al. 2006

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“…10 Both genetic types share a common pathomechanism: mutant mRNA transcripts containing CUG/CCUG expansions are retained in the nucleus and aggregate as nuclear foci. 11 RNA-binding proteins sequester in the nucleus, 12 resulting in mis-splicing of downstream effector genes (reviewed by Ranum and Cooper 13 ).…”

Section: Introductionmentioning

confidence: 99%

Identification of variants in MBNL1 in patients with a myotonic dystrophy-like phenotype

et al. 2016

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The myotonic dystrophies (DMs) are the most common inherited muscular disorders in adults. In most of the cases, the disease is caused by (CTG) n /(CCTG) n repeat expansions (EXPs) in non-coding regions of the genes DMPK (dystrophia myotonica-protein kinase) and CNBP (CCHC-type zinc-finger nucleic acid-binding protein). The EXP is transcribed into mutant RNAs, which provoke a common pathomechanism that is characterized by misexpression and mis-splicing. In this study, we screened 138 patients with typical clinical features of DM being negative for EXP in the known genes. We sequenced DMPK and CNBPassociated with DM, as well as CELF1 (CUGBP, Elav-like family member 1) and MBNL1 (muscleblind-like splicing regulator 1) -associated with the pathomechanism of DM, for pathogenic variants, addressing the question whether defects in other genes could cause a DM-like phenotype. We identified variants in three unrelated patients in the MBNL1 gene, two of them were heterozygous missense mutations and one an in-frame deletion of three amino acids. The variants were located in different conserved regions of the protein. The missense mutations were classified as potentially pathogenic by prediction tools. Analysis of MBNL1 splice target genes was carried out for one of the patients using RNA from peripheral blood leukocytes (PBL). Analysis of six genes known to show mis-splicing in the skeletal muscle gave no informative results on the effect of this variant when tested in PBL. The association of these variants with the DM phenotype therefore remains unconfirmed, but we hope that in view of the key role of MBNL1 in DM pathogenesis our observations may foster further studies in this direction.

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“…DM1 is linked to the expansion of a CTG repeat in the 3 0 -untranslated region of the dystrophia myotonica protein kinase gene (DMPK) localized on chromosome 19q13.3. 1,2 Although it has been suggested that haploinsufficiency and position effect variegation may contribute to DM1 phenotype, there is increasing evidence that the accumulation of mutant DMPK mRNA with expanded CUG repeats [3][4][5][6][7][8] has a central function in the pathogenetic mechanism. 9,10 Induced expression of expanded CUG repeats in a transgenic mouse model resulted in a DM1 phenotype, which reverted to normal when the induction was switched off.…”

Section: Introductionmentioning

confidence: 99%

Correction of dystrophia myotonica type 1 pre-mRNA transcripts by artificial trans-splicing

et al. 2008

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Dystrophia myotonica type 1 (DM1), the most common muscular dystrophy in adults, results from expansion of a CTG repeat in the 3 0 -untranslated region of the dystrophia myotonica protein kinase gene (DMPK). Correction of the mutant DMPK transcript is a potential therapeutic strategy in DM1. We investigated the efficacy of artificial trans-splicing molecules (ATMs) to target and correct DMPK transcripts. ATMs designed to target intron 14 of DMPK pre-mRNA transcripts were tested for their ability to trans-splice the transcripts of a DMPK mini-gene construct and the endogenous DMPK transcripts of human myosarcoma cells (CCL-136). On agarose gel electrophoresis analysis, six of eight ATMs showed trans-splicing efficacy when applied to DMPK mini-gene construct transcripts, of which three were able to trans-splice endogenous DMPK pre-mRNA transcripts in myosarcoma cells, with trans-splicing efficiency ranging from 1.81 to 7.41%. These findings confirm that artificial trans-splicing can repair DMPK pre-mRNA and provide proof-of-principle evidence for this approach as potential therapeutic strategy for DM1.

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Foci of trinucleotide repeat transcripts in nuclei of myotonic dystrophy cells and tissues.

Cited by 549 publications

References 27 publications

Reversible model of RNA toxicity and cardiac conduction defects in myotonic dystrophy

Reversible model of RNA toxicity and cardiac conduction defects in myotonic dystrophy

Identification of variants in MBNL1 in patients with a myotonic dystrophy-like phenotype

Correction of dystrophia myotonica type 1 pre-mRNA transcripts by artificial trans-splicing

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