My lab is combining electrophysiology, genetics and molecular biology in Drosophila to examine the structure, function and development of neural circuits. We use targeted expression of genes to identified sensory neurons in order to block the function or alter the development of synaptic circuits. For example, targeted expression of the anatomical marker lacZ reveals the structure of sensory neurons and the timing of axon growth into the nervous system while targeted expression of tetanus toxin to these same sensory neurons reveals their function by removing them from the circuit.

R. K. Murphey

Developmental Neuroscience;
Synaptogenesis of Simple
Nervous Systems

Image: Reflexes in Drosophila. (Reddy et al., 1997)

 

We have adapted standard electrophysiological techniques to Drosophila in order to assess the neural function directly by targeting toxins to subsets of sensory neurons, blocking synaptic transmission and exploring the consequences for reflex function and behavior. We then use these results and these methods to examine the assembly process and its disruption by various mutations. For example, we have discovered that mutations in cytoplasmic motors like the dynein complex affect axon growth and ultimately synaptic connectivity. We are in the process of determining how these cytoplasmic motors disrupt axon growth and synaptic connectivity by following their development during metamorphosis. Finally, we are determining how mutations in cytoplasmic motors disrupt synaptic connections using intracellular recording.

 

Representative Publications:

Murphey, R. K. and T. A. Godenschwege (2002). "New roles for ubiquitin in the assembly
and function of neuronal circuits." Neuron 36(1): 5-8.

Godenschwege, T. A., H. Hu, X. Shan-Crofts, C. S. Goodman and R. K. Murphey (2002).
"Bi-directional signaling by Semaphorin 1a during central synapse formation in
Drosophila." Nat Neurosci 5(12): 1294-301.

Godenschwege, T. A., J. H. Simpson, X. Shan, G. J. Bashaw, C. S. Goodman and R. K.
Murphey (2002). "Ectopic expression in the giant fiber system of Drosophila reveals
distinct roles for roundabout (Robo), Robo2, and Robo3 in dendritic guidance and
synaptic connectivity." J Neurosci 22(8): 3117-29.

Allen, M.J., X. Shan and R.K. Murphey (2000). A role for Drosophila Drac1 in neurite outgrowth and synaptogenesis in the giant fiber system. Molecular and Cellular Neuroscience. Mol Cell Neuroscience 16; 754-765.

Allen, M.J., X. Shan, P. Caruccio, S. Froggett and R.K. Murphey. (1999). Targeted expression of truncated Glued disrupts giant fiber synapse formation in Drosophila. J. Neurosci. 19, 9374-9384.

Murphey, R.K., Caruccio, P.C., Getzinger, M., Westgate, P., Phillis, R. (1999) Dynein-dynactin function and sensory axon growth during Drosophila metamorphosis: a role of retrograde motors. Dev. Biol. 209(1), 86-97.

Jin, P., Griffith, L., Murphey, R.K. (1998). Presynaptic calcium-calmodulin dependent protein kinase II regulates habituation of a simple reflex in adult Drosophila. J. Neurosci. (in press).

Killian, K.A. and Murphey, R.K. (1998). Target neuron specification of short-term synaptic facilitation and depression in the cricket CNS. J. Neurobiol. (in press).

Trimarchi, J., Jin, P., and Murphey, R.K. (1998). Controlling the motor neuron. In, The neuromuscular junction in Drosophila. Budnik, V. and S. Gramates, eds. Academic Press (in press).

Reddy, S., Jin, P., Trimarchi, J., Caruccio, P., Phillis, R., and Murphey, R.K. (1997). Mutant molecular motors disrupt neural circuits in Drosophila. J. Neurobiol. 33:711-723.

Trimarchi, J.R. and Murphey, R.K. (1997). The shaking-B2 mutation disrupts electrical synapses in a flight circuit in adult Drosophila. J. Neurosci 17:4700-4710.
 
Phillis, R., Statton, D., Caruccio, P., and Murphey, R.K. (1996). Mutations in the 8 kDa dynein light chain gene disrupts sensory axon projections in the Drosophila imaginal CNS. Development 122:2955-2963.
 
Murphey, R.K. and Davis, G.W. (1994). Retrograde signaling and synaptic function. J. Neurobiol. 25(6): 595-758.

Davis, G.W. and Murphey, R.K. (1994). Retrograde signaling and the development of transmitter release properties in the invertebrate nervous system. J. Neurobiology 25:740-756.

Davis, G.W. and Murphey, R.K. (1994). Long-term regulation of short-term transmitter release properties: Retrograde signaling and synaptic development. Trends Neurosci. 17: 9-13.

Hill, A., Edwards, D. H., and Murphey, R. K. (1994) The effect of neuronal growth on synaptic integration. J. Comput. Neurosci., 1(3): 239-254.

Phillis, R.W., Bramlage, A.T., Wotus, C., Whittaker, A., Gramates, L.S., Seppala, D., Farahanchi, F., Caruccio, P., and Murphey, R.K. (1993). Isolation of mutations affecting neural circuitry required for grooming behavior in Drosophila melanogaster. Genetics 133: 581-592.
Davis, G.W. and Murphey, R.K. (1993). A role for postsynaptic neurons in determining presynaptic release properties in the cricket CNS: evidence for retrograde control of facilitation. J. Neurosci. 13(9): 3827-3838.

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