Journal Article

Elevation of RNA-binding protein CUGBP1 is an early event in an inducible heart-specific mouse model of myotonic dystrophy

De Biasi, Mariella, Taffet, George, Cooper, Thomas A., Wang, Guey-Shin, Kearney, Debra L.

2007

Overview

Myotonic dystrophy type 1 (DM1) is caused by a CTG trinucleotide expansion in the 3' untranslated region (3' UTR) of DM protein kinase (DMPK). The key feature of DM1 pathogenesis is nuclear accumulation of RNA, which causes aberrant alternative splicing of specific pre-mRNAs by altering the functions of CUG-binding proteins (CUGBPs). Cardiac involvement occurs in more than 80% of individuals with DM1 and is responsible for up to 30% of disease-related deaths. We have generated an inducible and heart-specific DM1 mouse model expressing expanded CUG RNA in the context of DMPK 3' UTR that recapitulated pathological and molecular features of DM1 including dilated cardiomyopathy, arrhythmias, systolic and diastolic dysfunction, and mis-regulated alternative splicing. Combined in situ hybridization and immunofluorescent staining for CUGBP1 and CUGBP2, the 2 CUGBP1 and ETR-3 like factor (CELF) proteins expressed in heart, demonstrated elevated protein levels specifically in nuclei containing foci of CUG repeat RNA. A time-course study demonstrated that colocalization of MBNL1 with RNA foci and increased CUGBP1 occurred within hours of induced expression of CUG repeat RNA and coincided with reversion to embryonic splicing patterns. These results indicate that CUGBP1 upregulation is an early and primary response to expression of CUG repeat RNA.

• Publisher: American Society for Clinical Investigation
• Subject: Alternative Splicing / Animals / Binding proteins / Biomedical research / Cardiac arrhythmia / Cardiomyopathy / Causes of / CELF1 Protein / Cell Nucleus - chemistry / Cell Nucleus - metabolism / Development and progression / Disease Models, Animal / Genetic aspects / Health aspects / Heart / Insulin resistance / Kinases / Mice / Mice, Transgenic / Microscopy / Myocytes, Cardiac - chemistry / Myocytes, Cardiac - metabolism / Myocytes, Cardiac - pathology / Myotonic dystrophy / Myotonic Dystrophy - genetics / Myotonic Dystrophy - metabolism / Myotonic Dystrophy - pathology / Myotonin-Protein Kinase / Pathogenesis / Protein Serine-Threonine Kinases - genetics / Proteins / RNA, Messenger - analysis / RNA, Messenger - metabolism / RNA-Binding Proteins - analysis / RNA-Binding Proteins - genetics / RNA-Binding Proteins - metabolism / Trinucleotide Repeat Expansion