Studying the Effect of MBNL1 and MBNL2 Loss in Skeletal Muscle Regeneration.

Loss of function of members of the muscleblind-like (MBNL) family of RNA binding proteins has been shown to play a key role in the spliceopathy of RNA toxicity in myotonic dystrophy type 1 (DM1), the most common muscular dystrophy affecting adults and children. MBNL1 and MBNL2 are the most abundantly expressed members in skeletal muscle. A key aspect of DM1 is poor muscle regeneration and repair, leading to dystrophy.

Cardiac Pathology in Myotonic Dystrophy Type 1.

Myotonic dystrophy type 1 (DM1), the most common muscular dystrophy affecting adults and children, is a multi-systemic disorder affecting skeletal, cardiac, and smooth muscles as well as neurologic, endocrine and other systems. This review is on the cardiac pathology associated with DM1. The heart is one of the primary organs affected in DM1.

Modeling muscle regeneration in RNA toxicity mice.

RNA toxicity underlies the pathogenesis of disorders such as myotonic dystrophy type 1 (DM1). Muscular dystrophy is a key element of the pathology of DM1. The means by which RNA toxicity causes muscular dystrophy in DM1 is unclear.

Systemic therapy in an RNA toxicity mouse model with an antisense oligonucleotide therapy targeting a non-CUG sequence within the DMPK 3'UTR RNA.

Myotonic dystrophy type 1 (DM1), the most common adult muscular dystrophy, is an autosomal dominant disorder caused by an expansion of a (CTG)n tract within the 3' untranslated region (3'UTR) of the dystrophia myotonica protein kinase (DMPK) gene. Mutant DMPK mRNAs are toxic, present in nuclear RNA foci and correlated with a plethora of RNA splicing defects. Cardinal features of DM1 are myotonia and cardiac conduction abnormalities.

MBNL1 overexpression is not sufficient to rescue the phenotypes in a mouse model of RNA toxicity.

Myotonic dystrophy type 1 (DM1) is caused by an expanded (CTG)n tract in the 3'UTR of the DM protein kinase (DMPK) gene. The RNA transcripts produced from the expanded allele sequester or alter the function of RNA-binding proteins (MBNL1, CUGBP1, etc.).

Disease Phenotypes in a Mouse Model of RNA Toxicity Are Independent of Protein Kinase Cα and Protein Kinase Cβ.

Myotonic dystrophy type 1(DM1) is the prototype for diseases caused by RNA toxicity. RNAs from the mutant allele contain an expanded (CUG)n tract within the 3' untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. The toxic RNAs affect the function of RNA binding proteins leading to sequestration of muscleblind-like (MBNL) proteins and increased levels of CELF1 (CUGBP, Elav-like family member 1).

TWEAK Regulates Muscle Functions in a Mouse Model of RNA Toxicity.

Myotonic dystrophy type 1 (DM1), the most common form of muscular dystrophy in adults, is caused by toxic RNAs produced from the mutant DM protein kinase (DMPK) gene. DM1 is characterized by progressive muscle wasting and weakness. Therapeutic strategies have mainly focused on targeting the toxic RNA.

TWEAK/Fn14, a pathway and novel therapeutic target in myotonic dystrophy.

Myotonic dystrophy type 1 (DM1), the most prevalent muscular dystrophy in adults, is characterized by progressive muscle wasting and multi-systemic complications. DM1 is the prototype for disorders caused by RNA toxicity. Currently, no therapies exist.

NKX2-5, a modifier of skeletal muscle pathology due to RNA toxicity.

RNA toxicity is implicated in a number of disorders; especially those associated with expanded repeat sequences, such as myotonic dystrophy (DM1). Previously, we have shown increased NKX2-5 expression in RNA toxicity associated with DM1. Here, we investigate the relationship between NKX2-5 expression and muscle pathology due to RNA toxicity.

Evaluating the effects of CELF1 deficiency in a mouse model of RNA toxicity.

Myotonic dystrophy type 1 (DM1), the most common form of adult-onset muscular dystrophy, is caused by an expanded (CTG)n repeat in the 3' untranslated region of the DM protein kinase (DMPK) gene. The toxic RNA transcripts produced from the mutant allele alter the function of RNA-binding proteins leading to the functional depletion of muscleblind-like (MBNL) proteins and an increase in steady state levels of CUG-BP1 (CUGBP-ETR-3 like factor 1, CELF1). The role of increased CELF1 in DM1 pathogenesis is well studied using genetically engineered mouse models.

The RNA-binding protein Staufen1 is increased in DM1 skeletal muscle and promotes alternative pre-mRNA splicing.

In myotonic dystrophy type 1 (DM1), dystrophia myotonica protein kinase messenger ribonucleic acids (RNAs; mRNAs) with expanded CUG repeats (CUG(exp)) aggregate in the nucleus and become toxic to cells by sequestering and/or misregulating RNA-binding proteins, resulting in aberrant alternative splicing. In this paper, we find that the RNA-binding protein Staufen1 is markedly and specifically increased in skeletal muscle from DM1 mouse models and patients. We show that Staufen1 interacts with mutant CUG(exp) mRNAs and promotes their nuclear export and translation.

RNA toxicity in myotonic muscular dystrophy induces NKX2-5 expression.

Myotonic muscular dystrophy (DM1) is the most common inherited neuromuscular disorder in adults and is considered the first example of a disease caused by RNA toxicity. Using a reversible transgenic mouse model of RNA toxicity in DM1, we provide evidence that DM1 is associated with induced NKX2-5 expression. Transgene expression resulted in cardiac conduction defects, increased expression of the cardiac-specific transcription factor NKX2-5 and profound disturbances in connexin 40 and connexin 43.

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

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), which results in nuclear entrapment of the 'toxic' mutant RNA and interacting RNA-binding proteins (such as MBNL1) in ribonuclear inclusions. 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).

Expression of lexA targeted ribozyme in Escherichia coli BL-21 (DE3) cells.

Coding sequences for a hammerhead ribozyme designed to cleave lexA mRNA in a targeted manner was cloned under phage T7 promoter and expressed in E. coli strain BL-21 (DE3) expressing T7 RNA polymerase under the control of IPTG-inducible lac UV-5 promoter. Ribozyme expression in vivo was demonstrated by RNase protection assay.

Kinetic analysis of ribozyme-substrate complex formation in yeast.

Many RNA-mediated reactions in transcription, translation, RNA processing, and transport require assembly of RNA complexes, yet assembly pathways remain poorly understood. Assembly mechanisms can be difficult to assess in a biological context because many components interact in complex pathways and individual steps are difficult to isolate experimentally. Our previous studies of self-cleaving hairpin ribozymes showed that kinetic and equilibrium parameters measured in yeast agree well with parameters measured in vitro under ionic conditions that mimic the intracellular environment.