ROBERT E. MARC
Robert Marc
email: robert.marc@hsc.utah.edu		 Professor of Ophthalmology & Visual Science

The Marc Lab
Cellular Neuroscience
Neurobiology of Disease

B.S. 1971, University of Texas at El Paso; Ph.D. 1975, University of Texas Graduate School of Biomedical Sciences; Post-doctoral fellow, 1976-77 UCLA School of Medicine.

A multispectral image of ionotropic glutamate receptor activation in the bipolar cell layer of the rabbit retina.

1. The RED channel encodes GLYCINE, revealing ON-center cone bipolar cells that use metabotropic glutamate receptors to decode cone inputs.
2. The GREEN channel encodes kainate activated AGB permeation, demonstrating ionotropic glutamate receptor activation. The flickering cells are those that respond vigorously to 30 micromolar kainate.
3. The BLUE channel encodes endogenous GLUTAMATE signals. The pure blue cells are ON-center rod bipolar cells that also use metabotropic glutamate receptors.

RESEARCH:

Retinal Circuitry and Rewiring Induced by Neurodegenerative Disease

Dr. Marc's research focuses on the pathways involved in vertebrate retinal processing and their disruption in retinal degenerations, with emphasis on the connectivities of cells using the fast neurotransmitters glutamate, GABA, glycine and acetylcholine. Retinal pathways using ionotropic kainate, AMPA and NMDA receptors are visualized with organic cations that permeate activated receptor channels. These probes of excitation history can also be used in living, behaving organisms to map endogenous patterns of visually-driven excitation. The data are analyzed by quantitative light and electron microscopic digital imaging, and combined with neurotransmitter/metabolite maps and gene-gun dye particle marking of single cells to yield a comprehensive view of the types, numbers and connections of neurons which process visual signals. Inherited photoreceptor degenerations eventually trigger large-scale tissue remodeling and rewiring of the retina, and we are now mapping the nature of this corruptive rewiring. A major thrust in the laboratory is a high-throughput electron microscope imaging project - the largest synaptic wiring project in the world - now being initiated in collaboration with the UU SCI (Scientific Visualization and Imaging) Institute.

Selected Publications

Marc, R.E., Jones, B.W., Anderson, J.R., Kinard, K., Marshak, D.W., Wilson, J.H., Wensel, T.G., and Lucas, R.J. (2007) Neural reprogramming in retinal degenerations. Invest Ophthalmol Vis Sci, 48:3364-3371.

Marc, R.E., Kalloniatis, M., and Jones. B.W. (2005) Excitation mapping with the organic cation AGB2+. Vision Research, 45:3454-3468.

Jones, B.W. and Marc, R.E. (2005) Retinal remodeling during retinal degeneration. Experimental Eye Research, 81:121-244.

Marc, R.E., Jones, B.W., and Watt, C.B. (2005) Retinal remodeling: Circuitry revisions triggered by photoreceptor degeneration. In: Plasticity in the Visual system: from Genes to Circuits. Eds, Pinaud et al., Springer, pp. 33-54.

Rohrer, B., Blanco, R., Marc, R.E., Lloyd, M.B., Bok, D., Schneeweis, D.M., Reichardt, L.F. (2004) Functionally intact glutamate-mediated signaling in bipolar-cells of the Trkb knockout mouse retina. Visual Neurosci, 21:703-713.

Marc, R.E. (2004) "Retinal Neurotransmitters" in The Visual Neurosciences (Chalupa and Werner, Eds.). MIT Press, pp. 315-330.

Marc, R.E., Jones, B.W., Watt, C.B., and Strettoi, E. (2003) Neural Remodeling in Retinal Degeneration. Progress in Retinal and Eye Research, 22:607-655.

Jones, B.W., Watt, C.B., Frederick, J.M., Baehr, W., Chen, C.K., Levine, E.M., Milam, A.H., LaVail, M.M., and Marc, R.E. (2003) Retinal remodeling triggered by photoreceptor degenerations. J Comp Neurol, 464:1-16.

Marc, R.E., and Cameron, D. (2002) A molecular phenotype atlas of the zebrafish retina. J. Neurocytol., 30:593-654.

Marc, R.E., and Jones, B.W. (2002) Molecular phenotyping of retinal ganglion cells. J. Neurosci., 22:413-427.

Marc, R.E., and Liu, W.L. (2000) Fundamental GABAergic amacrine cell circuitries in the retina: Nested feedback, concatenated inhibition, and axosomatic synapses. J. Comp. Neurol., 425:560-582.

Marc, R.E. (1999) Mapping glutamatergic drive in the vertebrate retina with a channel permeant organic cation. J. Comp. Neurol., 407:47-64.

Marc, R.E. (1999) Kainate activation of horizontal, bipolar, amacrine and ganglion cells in the rabbit retina. J. Comp. Neurol., 407:65-76.

Kalloniatis, M., Marc, R.E., and Murry, R. (1996) Amino acid signatures in the primate retina. J. Neurosci., 16:6807-6829.

Marc, R.E., Murry, R., and Basinger, S.F. (1995) Pattern recognition of amino acid signatures in retinal neurons. J. Neurosci., 15:5106-5129.

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