This project will investigate the molecular mechanism of the nonsense-mediated mRNA decay (NMD) pathway in mammalian cells. mRNA decay plays a prominent role in regulation of gene expression. Specific cell signals can transiently stabilize unstable mRNAs or destabilize stable mRNAs to regulate protein expression. NMD is a specific mRNA decay pathway that rids the cell of aberrant mRNAs, which by mutation or erroneous processing fail to encode full-length protein. In human cells, this pathway is dependent on three hUpf proteins and a protein complex (called the exon-junction complex) that is deposited on mRNAs after pre-mRNA splicing. Assembly of the exon-junction complex and the hUpf proteins onto mRNAs with premature termination codons and their subsequent targeting for NMD will be studied with the goal of understanding the molecular mechanism of the NMD pathway in mammalian cells. The findings should provide valuable information about mRNA decay in mammalian cells, an important process in regulation of gene expression that is currently poorly understood. This project will result in generation of several valuable reagents, useful for studies of translation and mRNA decay. These will be freely available to researchers after publication. In addition, female graduate students as well as undergraduates will be directly involved in the latest techniques in gene expression research, and the research in this project will be invaluable in the PI's undergraduate teaching at University of Colorado at Boulder.
