Ravi K. Singh Lab
Assistant Professor, Pathology (Pediatric Pathology)
rsingh@mcw.edu
Muscle-powered movements govern lifespan and overall quality of human life. Our research aims to better understand how gene expression programs in cardiac and skeletal muscle respond to biological, nutritional, and environmental cues to grow and mature after birth, and to identify mechanisms contributing to aging-associated decline in muscle function (cardiac dysfunction and sarcopenia).
It is now clear that multiple mechanisms regulate gene expression soon after transcription including alternative pre-mRNA splicing and processing, mRNA export, localization, stability and control of translation. These post-transcriptional mechanisms increase proteomic diversity, or cause a change in protein abundance/distribution, ultimately affecting cellular or tissue function. It is not well understood how these mechanisms affect muscle function in the context of development, aging and disease.
What is alternative splicing and why is it important?
Alternative splicing is a process where pre-mRNA from a single gene selects different sets of exons (protein-coding segments) to generate multiple mRNAs (encoding different protein isoforms), and significantly increases proteomic diversity in mammals. RNA-sequencing studies indicate that >90% of human protein-coding genes are alternatively spliced and a majority of alternative splicing occurs in tissue-specific manner including brain, heart, and skeletal muscle. On the other hand, disruption in alternative splicing is also known to cause human diseases (Singh RK and Cooper TA, Trends Mol Med. 2012, (8):472). A major focus of our lab is to better understand how alternative splicing is regulated and integrates with other gene expression programs and cellular processes to optimize cardiac and skeletal function.
Current Projects
RNA binding proteins (or RBPs) regulate nearly all aspects of post-transcriptional gene expression including alternative splicing. Current projects in our lab stems from our and others鈥� finding that highly conserved RBPs of the RNA binding fox-1 homolog (Rbfox) family is important for regulating alternative splicing in cardiac and skeletal muscle. Of the three Rbfox genes, Rbfox1 and Rbfox2 are expressed in heart and skeletal muscle. Double knockout of Rbfox1 and Rbfox2 in adult skeletal muscle causes a ~50% reduction in muscle mass within 4 weeks (Singh et al. Cell Rep. 2018, 24(1):197), lack of Rbfox2 in developing mouse and human heart causes cardiomyopathy (Wei et al., Cell Reports 2015, (10)1521; Homsy et al., Science. 2015, 350(6265):1262; and our preliminary observation), and lack of RBFOX2 in myoblasts inhibits myogenesis (Singh et al. Mol Cell. 2014,55(4):592), emphasizing the importance of regulated splicing in cardiac and skeletal muscle function. Recent studies also suggest that alternative splicing, RBPs and other post-transcriptional gene regulatory mechanisms play a role in in aging-associated decline in muscle function. The objectives of research in our lab are:
- To identify the functional consequences of alternative splicing in modulation of gene expression programs and cellular processes to optimize heart and skeletal muscle function.
- To determine the role of RBPs and alternative splicing in promoting gender-biased functional differences in heart and skeletal muscle biology.
- To identify gene expression programs contributing to aging-associated decline in cardiac and skeletal muscle function.
We are using mouse genetics (classical and CRISPR-Cas9 tools), cell/molecular biology approaches, transcriptome-wide experimental and bioinformatic methods to address these questions.
Employment Opportunities
We are interested in motivated and discovery-driven individuals to join our group. Please contact us to initiate the conversation.
Staff
- Sushil Kumar, Postdoctoral Fellow
- Jacob Besler, Research Technologist I