Biosciences Graduate Program

Wayne A. Johnson, PhD


Professor of Molecular Physiology and Biophysics

Contact Information

Office: 6-472  BSB
Iowa City, IA 52242

Lab: 6-473, 6-566  BSB
Iowa City, IA 52242

Web: Departmental Profile


BS, Pharmacy, University of Wyoming
PhD, Pharmacology, University of Washington

Education/Training Program Affiliations

Biosciences Graduate Program
Department of Molecular Physiology and Biophysics PhD
Interdisciplinary Graduate Program in Genetics
Interdisciplinary Graduate Program in Neuroscience

Research Summary

Genetic analysis of locomotion behavior: molecular mechanisms of sensory signal transduction. Coordination of rhythmic locomotion such as crawling, swimming or walking depends upon a precisely balanced interplay between central and peripheral control mechanisms. Disruptions of this relationship caused by stroke, athletic injuries, peripheral neuropathy or osteoarthiritis can result in severe defects in motor control. Although significant advances have been made recently, we still have a relatively poor molecular understanding of how peripheral proprioceptive mechanosensory input is able to provide information about body position for moment to moment modifications of central mechanisms mediating rhythmic motor output. Does mechanosensory signaling in proprioceptive neurons designed to detect stretch or tension require a different signaling complex than neurons functioning in external touch sensation? We have developed a genetic model system in Drosophila to examine the molecular components of proprioceptive mechanosensation in type II multiple dendritic(md) sensory neurons. We have isolated a series of locomotion mutants displaying an unusual enhanced locomotion phenotype indicative of altered motor control. These mutant larvae crawl faster and farther with fewer stops and turns than wild-type larvae. One mutant gene encodes a Drosophila epithelial sodium channel subunit, Pickpocket1, making it a candidate mechanotransduction channel. We are currently utilizing the genomic and genetic resources available in the Drosophila system to clone other enhanced locomotion genes in our collection. Combined with an electrophysiological analysis of multiple dendritic neuron function, this molecular information should allow a more detailed characterization of their physiological functions and their relationships to each other.

Date Last Modified: 06/07/2014 - 21:56:23