We study mechanotransduction by hair cells, the sensory cells of the inner ear. Being interested in what molecules make up the transduction apparatus, the collection of channels, linker molecules, and motors that mediate transduction, we take a frank reductionist approach. We start with physiology: when you mechanically stimulate a hair cell, what are the characteristics of the resulting receptor current? Studying transduction currents, we learn how transduction channels open and close in response to mechanical forces, and how the adaptation motor responds to sustained forces and allows channels to close. These experiments have suggested candidate families for the transduction channel and the adaptation motors, for example, and we use these clues to identify, clone, and characterize the responsible molecules. Because the scarcity of hair cells prevent extensive biochemical characterization, we express transduction molecules in vitro and determine properties that can be compared with the physiology of transduction. This approach has proven highly successful for identification of the adaptation motor, myosin-1c; the tip link, cadherin-23; and the calcium pump, PMCA2a.
Recently, we have applied proteomics techniques to every aspect of the lab's research program. Modern mass spectrometry is remarkably comprehensive in its ability to identify and quantify molecules and has the sensitivity to detect scarce hair-bundle proteins.
Now that we know the several hundred most abundant proteins of the hair bundle, we can begin to dissect how the hair bundle is assembled during development. Moreover, our knowledge of several proteins of the transduction complex, together with the sensitivity of mass spectrometry, allows us to take a biochemical approach to identification of the transduction channel, one of the central mysteries of the auditory system.
"These Ai14 mice harbor a targeted mutation of the Gt(ROSA)26Sor locus with a loxP-flanked STOP cassette preventing transcription of a CAG promoter-driven red fluorescent protein variant (tdTomato), and may be useful as a Cre reporter strain. TdTomato is expressed following Cre-mediated recombination."
Transgenic strain allows for temporal and cell-specific targeting of Atoh1.
"When these Math1-CreERT2 mice are bred with mice containing a loxP-flanked sequence of interest, tamoxifen-inducible, Cre-mediated recombination will result in deletion of the flanked sequences in Math1 expressing cells (the entire dorsal neural tube from posterior rhombomere 1 to the spinal cord); making them useful in studying cerebellum development and fate mapping of Math1/Atoh1 cells."