Project description:Misregulated alternative splicing appears to be a major factor in the pathogenesis of myotonic dystrophy. The present study was done to further explore alternative splicing in this condition by doing exon-level analysis of mRNA from skeletal muscle of 8 subjects with type 1 myotonic dystrophy, 7 subjects with type 2 myotonic dystrophy, 8 disease controls (subjects with facioscapulohumeral muscular dystrophy), and 8 healthy controls . The ratios of signals from the various exons of a gene provided an index of altered exon inclusion/exclusion that was independent of the overall expression of that gene. There were numerous transcripts for which there was evidence of abnormal alternative splicing in subjects with myotonic dystrophy. For many of these transcripts, the abnormal splicing was confirmed by an independent RT-PCR approach. 31 subjects, one sample per subject, four groups: healthy subjects (n = 8), facioscapulohumeral dystrophy (n = 8), type 1 myotonic dystrophy (n = 8), type 2 myotonic dystrophy (n = 7)
Project description:Misregulated alternative splicing appears to be a major factor in the pathogenesis of myotonic dystrophy. The present study was done to further explore alternative splicing in this condition by doing exon-level analysis of mRNA from skeletal muscle of 8 subjects with type 1 myotonic dystrophy, 7 subjects with type 2 myotonic dystrophy, 8 disease controls (subjects with facioscapulohumeral muscular dystrophy), and 8 healthy controls . The ratios of signals from the various exons of a gene provided an index of altered exon inclusion/exclusion that was independent of the overall expression of that gene. There were numerous transcripts for which there was evidence of abnormal alternative splicing in subjects with myotonic dystrophy. For many of these transcripts, the abnormal splicing was confirmed by an independent RT-PCR approach.
Project description:Distinct RNA-mediated impacts on alternative splicing and extracellular matrix gene expression in a mouse model of myotonic dystrophy. Myotonic dystrophy (DM1) is associated with expression of expanded CTG DNA repeats as RNA (CUGexp RNA). To test whether CUGexp RNA creates a global splicing defect, we compared skeletal muscle of two mouse DM1 models, one expressing a CTGexp transgene, and another homozygous for a defective Mbnl1 gene. Strong correlation in splicing changes for ~100 new Mbnl1-regulated exons indicates loss of Mbnl1 explains >80% of the splicing pathology due to CUGexp RNA. In contrast, only about half of mRNA level changes can be attributed to loss of Mbnl1, indicating CUGexp RNA has Mbnl1-independent effects, particularly on mRNAs for extracellular matrix (ECM) proteins. We propose that CUGexp RNA causes two separate effects: loss of Mbnl1 function, disrupting splicing, and loss of another function that disrupts ECM mRNA regulation, possibly mediated by MBNL2. These findings reveal unanticipated similarities between DM1 and other muscular dystrophies. MBNL1 knockout and HSALR mice on FVB background. To test whether CUGexp RNA creates a global splicing defect, we compared skeletal muscle of two mouse DM1 models, one expressing a CTGexp transgene, and another homozygous for a defective Mbnl1 gene. These samples were compared to the skeletal muscle of a wildtype mouse.
Project description:The prevailing patho-mechanistic paradigm for myotonic dystrophy (DM) is that the aberrant presence of embryonic isoforms is responsible for many, if not most, aspects of the pleiotropic disease phenotype. In order to identify such aberrantly expressed isoforms in skeletal muscle of DM type 1 (DM1) and type 2 (DM2) patients, we utilized the Affymetrix exon array to characterize the largest collection of DM samples analyzed to date, and included non-DM dystrophic muscle samples (NMD) as disease controls. For the exon array profiling on the Human Exon 1.0 ST array (Affymetrix Santa Clara, CA) we used a panel of 28 skeletal muscle biopsies from DM1 (n=8), DM2 (n=10), Becker muscular dystrophy, BMD, (n=3), Duchenne muscular dystrophy, DMD (n=1), Tibial muscular dystrophy, TMD, (n=2) and normal skeletal muscle (n=4). Normal control RNAs were purchased commercially. .CEL files were generated with a pre-commercial version of the Affymetrix processing software, and the headers might be non-standard. In our lab, users of the Partek software could use them, whereas users of GeneSpring had to modify the header information.
Project description:MBNL1 is a known splicing factor and is related to Myotonic Dystrophy (DM). This study examines the tissue specific splicing patterns of MBNL1 using a mutant and wild type mouse across three tissues (heart,brain,quadricep) related publications: Aberrant alternative splicing and extracellular matrix gene expression in mouse models of myotonic dystrophy. Du H, etal Nat Struct Mol Biol. 2010 Feb;17(2):187-93. and Hum Mol Genet. 2006 Jul 1;15(13):2087-97. Failure of MBNL1-dependent post-natal splicing transitions in myotonic dystrophy. Lin X, Miller JW, Mankodi A, Kanadia RN, Yuan Y, Moxley RT, Swanson MS, Thornton CA. We examined quadricep,heart and brain of a mouse MBNL1 mutant to test whether MBNL mutants creates a tissue specific splicing defect. These samples were compared to the tissues of a wild type mouse.
Project description:The prevailing patho-mechanistic paradigm for myotonic dystrophy (DM) is that the aberrant presence of embryonic isoforms is responsible for many, if not most, aspects of the pleiotropic disease phenotype. In order to identify such aberrantly expressed isoforms in skeletal muscle of DM type 1 (DM1) and type 2 (DM2) patients, we utilized the Affymetrix exon array to characterize the largest collection of DM samples analyzed to date, and included non-DM dystrophic muscle samples (NMD) as disease controls.