MicroRNAs have burst into molecular biology as the dark matter of the genome. They are 20-22 base long RNAs produced in mammalian cells that have gone undetected till the last decade. Only now are we beginning to realize the critical role they play in regulation of gene expression in mammalian cells. The differentiation of C2C12 myoblasts into myotubes is paradigmatic of the differentiation of satellite cells into myotubes in adult skeletal muscle. We hypothesize that microRNAs induced during muscle differentiation are important for inducing cell quiescence and promoting myogenic differentiation. The goal of this project is to characterize the microRNAome of skeletal muscle cells with the intent of detecting microRNAs involved in differentiation of C2C12 myoblasts and primary satellite cells. We have identified five microRNAs that are induced during the differentiation process and plan to identify any more that behave similarly. Selective de-regulation of the levels of specific microRNAs (both increase and decrease) will determine how the microRNAs affect cell quiescence and differentiation of the muscle cells. Preliminary results reveal that two key genes involved in DNA replication and cell cycle progression are targets of the microRNAs. We will determine the role of down regulation of these and other genes by the microRNAs in establishment of cell-quiescence in both myoblasts and non-muscle cells. Finally the direct targets of the microRNAs will be ascertained by a two-pronged approach using microarray hybridizations and bioinformatics. Putative targets important for establishment of cell quiescence will be tested to ascertain whether they are indeed repressed by microRNAs during differentiation and how such repression contributes to cell quiescence.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR053948-05
Application #
8120772
Study Section
Skeletal Muscle and Exercise Physiology Study Section (SMEP)
Program Officer
Boyce, Amanda T
Project Start
2007-09-01
Project End
2013-07-31
Budget Start
2011-08-01
Budget End
2013-07-31
Support Year
5
Fiscal Year
2011
Total Cost
$303,379
Indirect Cost
Name
University of Virginia
Department
Biochemistry
Type
Schools of Medicine
DUNS #
065391526
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Mueller, Adam C; Cichewicz, Magdalena A; Dey, Bijan K et al. (2015) MUNC, a long noncoding RNA that facilitates the function of MyoD in skeletal myogenesis. Mol Cell Biol 35:498-513
Dey, Bijan K; Pfeifer, Karl; Dutta, Anindya (2014) The H19 long noncoding RNA gives rise to microRNAs miR-675-3p and miR-675-5p to promote skeletal muscle differentiation and regeneration. Genes Dev 28:491-501
Dey, Bijan K; Mueller, Adam C; Dutta, Anindya (2014) Long non-coding RNAs as emerging regulators of differentiation, development, and disease. Transcription 5:e944014
Dey, Bijan K; Gagan, Jeffrey; Yan, Zhen et al. (2012) miR-26a is required for skeletal muscle differentiation and regeneration in mice. Genes Dev 26:2180-91
Gagan, Jeffrey; Dey, Bijan K; Layer, Ryan et al. (2012) Notch3 and Mef2c proteins are mutually antagonistic via Mkp1 protein and miR-1/206 microRNAs in differentiating myoblasts. J Biol Chem 287:40360-70
Gagan, Jeffrey; Dey, Bijan K; Dutta, Anindya (2012) MicroRNAs regulate and provide robustness to the myogenic transcriptional network. Curr Opin Pharmacol 12:383-8
Dey, Bijan K; Mueller, Adam C; Dutta, Anindya (2012) Non-micro-short RNAs: the new kids on the block. Mol Biol Cell 23:4664-7
Gagan, Jeffrey; Dey, Bijan K; Layer, Ryan et al. (2011) MicroRNA-378 targets the myogenic repressor MyoR during myoblast differentiation. J Biol Chem 286:19431-8
Dey, Bijan K; Gagan, Jeffrey; Dutta, Anindya (2011) miR-206 and -486 induce myoblast differentiation by downregulating Pax7. Mol Cell Biol 31:203-14
Sarkar, Sukumar; Dey, Bijan K; Dutta, Anindya (2010) MiR-322/424 and -503 are induced during muscle differentiation and promote cell cycle quiescence and differentiation by down-regulation of Cdc25A. Mol Biol Cell 21:2138-49

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