Although researchers know a great deal about the biophysical
basis of hearing, not much is known about the molecules which
are required for mechanotransduction in vertebrate sensory
hair cells. In Christiane Nsslein-Volhard's laboratory at
the Max Planck Institute of Developmental Biology in
Tbingen/Germany, a new study on zebrafish mutants with
problems in balance has lead to the identification of eight
genes which are required for inner ear and lateral line
function. Five of these genes appear to have a specific role
within sensory hair cells since they are required for the
production of extracellular potential generation, a measure
of hair cell function.
The results of the study can be found in the February issue of Neuron (Nicolson et al. 1998). A strong point of the work is the analysis of the zebrafish mutants at different levels of neurobiology, from behavior and anatomy to physiology. This was achieved by fruitful collaboration between scientists at the Max Planck Institute of Developmental Biology and the Ear, Nose, and Throat Clinic in Tbingen, Germany.
The zebrafish vestibular/auditory mutants are similar to mice shaker/waltzer type mutants in that they also make circular motions and have problems with maintaining balance. Behavioral tests suggest that some of these zebrafish mutants do not sense gravity, i.e. they swim as if they are in a weightless environment. A major advantage of using zebrafish to study the inner ear is the transparency of the larval organ which allows researchers to directly view sensory hair cells in live fish. In addition, the transparent larvae are suitable for imaging of neuronal activity within the brain and peripheral nervous system.
Localization of the defects to the sensory hair cells or primary neurons in the mutants was achieved by a non
Contact: Teresa Nicolson