|Elizabeth A. Connor
Associate Professor of Biology, University of Massachusetts
Ph.D.: University of Vermont
Developmental Neurobiology: Synapse Development, Maintenance, and Regeneration
The neuromuscular junction, the site of communication between a motor neuron and a skeletal muscle fiber, is composed of cells which are specialized in molecular and structural composition to form the "machinery" required for successful synaptic transmission. We are studying the factors involved in the formation and maintenance of the neuromuscular junction.
To determine the role of the muscle fiber in the functional maintenance of frog nerve terminals we examined the function of nerve terminals deprived of muscle using an optical assay of presynaptic activity. We found that nerve terminals remained at synaptic sites for long periods after target removal and retained their ability to release synaptic vesicles. In experiments where we determined the response of individual nerve terminals to loss of target, by repeated in vivo imaging, we demonstrated that a healthy muscle fiber was not required for maintenance of a nerve terminal. Instead, nonmuscle cues are likely to confer stability to frog motor nerve terminals.
Our efforts to identify the nonmuscle factors that contribute to the stabilization of motor nerve terminals at synaptic sites are focusing on the terminal Schwann cell and extracellular matrix. These experiments will expand our understanding of the molecular and cellular interactions that govern synaptic maintenance and plasticity.
Dunaevsky, A. and E. A. Connor (2000). "F-actin is concentrated in nonrelease domains at frog neuromuscular junctions." J Neurosci 20(16): 6007-12.
Dunaevsky, A. and E. A. Connor (1998). "Stability of frog motor nerve terminals in the absence of target muscle fibers." Dev Biol 194(1): 61-71.
Connor, E.A. (1997) Developmental regulation of interstitial cell density in skeletal muscle. J. Neurocytol. 26: 23-32.
Dunaevsky, A. and Connor, E.A. (1998) Stability of frog motor nerve terminals in the absence of target muscle fibers. Dev. Biol. 194, 61-71.
Connor, E.A. (1997) Developmental regulation of interstitial cell density in skeletal muscle. J. Neurocytol. 26, 23-32.
Connor E.A., Dunaevsky, A., Griffiths, D.J.G., Hardwick, J.C. and Parsons, R.L. (1997) Transmitter release differs at snake twitch and tonic endplates during potassium-induced nerve terminal depolarization. J. Neurophysiol. 77, 749-760.
Dunaevsky, A. and Connor, E.A. (1995) Long term maintenance of presynaptic function in the absence of target muscle fibers. J. Neurosci. 15, 6137-6144.
Connor, E.A., Qin, K., Yankelev, H. and DeStefano, D. (1994) Synaptic activity and connective tissue remodeling in denervated frog muscle. J. Cell Biol. 127, 1435-1445.