In the quest to identify genes that regulate dopamine signaling, the UMass Amherst researchers quickly recognized that dopamine acts through proteins used by other neurotransmitters in other nervous system cells. "So we couldn't use traditional genetic tools to study dopamine signaling. We needed to develop a new method to study protein function in individual cells in multicellular organisms," Chase notes.
The technique they developed takes advantage of nonsense-mediated decay (NMD), a surveillance mechanism present in all eukaryotic organisms. NMD destroys aberrant mRNA molecules that can arise naturally through mutation during transcription or mRNA processing.
"In our strategy, we replace the normal copy of a gene with a tagged version that targets the gene's mRNA for destruction by NMD," Chase explains. "We then remove NMD from all the organism's cells. Without NMD present, the replacement gene is expressed normally in all cells. We then knock down expression of the gene cell-specifically by restoring NMD activity only in cells we select."
He adds, "This cell-specific restoration of NMD activity is easy and can also be controlled in time. Thus, using NMD we can not only remove gene function in individual cell types, we can control exactly when gene function is removed in that cell type. This gives complete control of gene expression and allows one to investigate the function of any gene in any cell type at any time."
"With this very powerful new technique, now you can identify an individual gene and you can ask whether it plays a role in the behavior of interest. All these genes are expressed in our brains, so we are learning about all sorts of fa
|Contact: Janet Lathrop|
University of Massachusetts at Amherst