Biochemistry and Molecular Biology
Penn State Science
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Melissa Rolls

Melissa Rolls

Main Content

  • Associate Professor of Biochemistry and Molecular Biology
  • Chair of the Molecular, Cellular and Integrative Biosciences Graduate Program
118 Life Sciences Building
University Park, PA 16802
Phone: (814) 867-1395

Research Interests

Subcellular compartmentalization of neurons

Graduate Programs


Research Summary

The Rolls lab uses live imaging and Drosophila genetics to investigate two broad areas of neuronal cell biology:
1. neuron polarity, focusing on microtubule polarity
2. neuronal responses to injury including degeneration and regeneration.

Microtubule polarity:
Neurons receive information from dendrites and send information through axons, each neuron thus has two major functionally and molecularly distinct compartments. We have found that microtubules in these two compartments have opposite orientation in all types of Drosophila neurons. This opposite polarity likely underlies many differences between axons and dendrites, so we are working to identify mechanisms that allow a single cell to set up two different arrangements of microtubules.

Neuronal responses to injury:

Many neurons must remain intact for an animal’s entire life. In order to do this, they must be able to recover from injury. Two aspects of this recovery are degeneration of regions too damaged to be repaired and regeneration of regions required for function. We study several types of degeneration and regeneration at the single cell level in whole intact animals and aim to identify molecular mechanisms that control the morphological changes we track.

Rolls figure 1

Figure 1: An example of controlled in vivo neuron injury. Using a pulsed UV laser we can sever single axons in whole animals. Neuronal microtubules are labeled with GFP and glial membranes are labeled with RFP.


Rolls figure 2

Figure 2: Severing axons close to the cell body elicits regeneration of an axon from a dendrites. The cell is labeled with RFP, and was injured and tracked over several days in whole intact animals. In this cell new growth can be seen emerging from the dendrite on the right.

Selected Publications


  • Stone, M. C., Rao, K., Gheres, K. W., Kim, S., Tao, J., La Rochelle, C., Folker, C. T., Sherwood, N. T., Rolls, M. M. Normal spastin gene dosage is specifically required for axon regeneration. Cell Reports in press.
  • Hill, S. E., Parmar, M., Gheres, K. W., Guignet, M. A., Huang, Y., Jackson, F. R., Rolls, M. M. Development of dendrite polarity in Drosophila neurons. Neural Development in press.
  • Stewart, A., Tsubouchi, A., Rolls, M. M., Tracey, W. D., Sherwood, N. T. (2012) Katanin p60-like1 promotes microtubule growth and terminal dendrite stability in the larval class IV sensory neurons of Drosophila. Journal of Neuroscience 32: 11631-11642.
  • Chen, L., Stone, M. C., Tao, J., Rolls, M. M. (2012) Axon injury and stress trigger a microtubule-based neuroprotective pathway. Proceeding of the National Academy of Sciences, USA 109: 11842-11847.
  • Nguyen, M. M., Stone, M. C., Rolls, M. M. (2011) Microtubules are organized independently from the centrosome in Drosophila neurons. Neural Development 6: 38 (1-16).
  • Tao, J., Rolls, M. M. (2011) Dendrites have a rapid program of injury-induced degeneration that is molecularly distinct from developmental pruning. Journal of Neuroscience 31: 5398-5405.
  • Mattie, F. J., Stackpole, M. M., Stone, M. C., Clippard, J. R., Rudnick, D. A., Qiu, Y., Tao, J., Allender, D. L., Parmar, M., Rolls, M. M. (2010) Directed microtubule growth, +TIPs and kinesin-2 are required for uniform microtubule polarity in dendrites. Current Biology 21: 2169-2177.
  • Stone, M. C., Nguyen, M. M., Tao, J., Allender, D. L., Rolls, M. M. (2010) Global upregulation of microtubule dynamics and polarity reversal during regeneration of an axon from a dendrite. Molecular Biology of the Cell  21: 767-777.
  • Stone, M. C., Roegiers, F., Rolls, M. M. (2008) Microtubules have opposite orientation in axons and dendrites of Drosophila neurons. Molecular Biology of the Cell 19: 4122-4129.