Myotonic dystrophy (DM) is caused by nucleotide expansions of CUG and CCUG in the non-coding regions of the dystrophia myotonia protein kinase gene (DMPK) and the Zn finger 9 gene (ZNF9) respectively. Patients with the CUG expansions have type I myotonic dystrophy (DM1) and patients with the CCUG expansions have type II myotonic dystrophy (DM2). Patients with DM1 and DM2 display the same symptoms, suggesting both CUG and CCUG expansions cause DM through the same mechanism. The hypothesis for how these non-coding expansions cause DM is through an RNA gain-of-function mechanism; the expanded CUG and CCUG repeat RNAs sequester the MBNL RNA binding protein and also indirectly increase the protein levels of another RNA binding protein (CUG-BP), which disrupts the normal cellular function of MBNL and CUG-BP. MBNL and CUG-BP are pre-mRNA splicing factors that appear to function antagonistically. Changing their """"""""active"""""""" concentration results in the mis-regulation of alternative splicing of multiple transcripts with a final outcome of DM for people with CUG and CCUG expansions. The focus of this proposal is to determine the role of MBNL in the disease state (DM) as well as in normal cells. To accomplish these goals we are using a combination of bioinformatics, biochemical, biophysical and structural methods.
Aim 1. Identify cellular targets of MBNL and determine the mechanisms through which MBNL regulates pre- mRNA splicing.
Aim 2. Biochemical and structural characterization of CUG and CCUG repeats alone and in complex with MBNL. Our goal is to understand the molecular mechanisms that cause DM. This understanding will help lead to the development of therapies to help the many people (1 in 8000) that have this most common form of adult onset muscular dystrophy. ? ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
1R01AR053903-01
Application #
7132112
Study Section
Skeletal Muscle and Exercise Physiology Study Section (SMEP)
Program Officer
Nuckolls, Glen H
Project Start
2006-08-01
Project End
2011-07-31
Budget Start
2006-08-01
Budget End
2007-07-31
Support Year
1
Fiscal Year
2006
Total Cost
$255,535
Indirect Cost
Name
University of Oregon
Department
Biochemistry
Type
Organized Research Units
DUNS #
948117312
City
Eugene
State
OR
Country
United States
Zip Code
97403
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Purcell, Jamie; Oddo, Julia C; Wang, Eric T et al. (2012) Combinatorial mutagenesis of MBNL1 zinc fingers elucidates distinct classes of regulatory events. Mol Cell Biol 32:4155-67
Gates, Devika P; Coonrod, Leslie A; Berglund, J Andrew (2011) Autoregulated splicing of muscleblind-like 1 (MBNL1) Pre-mRNA. J Biol Chem 286:34224-33
Cass, Danielle; Hotchko, Rachel; Barber, Paul et al. (2011) The four Zn fingers of MBNL1 provide a flexible platform for recognition of its RNA binding elements. BMC Mol Biol 12:20
Voelker, Rodger B; Berglund, J Andrew (2010) Two ways to misregulate mRNAs in myotonic dystrophy. Nat Struct Mol Biol 17:141-2
Warf, M Bryan; Berglund, J Andrew (2010) Role of RNA structure in regulating pre-mRNA splicing. Trends Biochem Sci 35:169-78
Goers, Emily S; Purcell, Jamie; Voelker, Rodger B et al. (2010) MBNL1 binds GC motifs embedded in pyrimidines to regulate alternative splicing. Nucleic Acids Res 38:2467-84
Warf, M Bryan; Diegel, Julien V; von Hippel, Peter H et al. (2009) The protein factors MBNL1 and U2AF65 bind alternative RNA structures to regulate splicing. Proc Natl Acad Sci U S A 106:9203-8
Warf, M Bryan; Nakamori, Masayuki; Matthys, Catherine M et al. (2009) Pentamidine reverses the splicing defects associated with myotonic dystrophy. Proc Natl Acad Sci U S A 106:18551-6
Goers, Emily S; Voelker, Rodger B; Gates, Devika P et al. (2008) RNA binding specificity of Drosophila muscleblind. Biochemistry 47:7284-94

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