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.
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.
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.
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.