Compartmentalization and axon guidance in the Drosophila brain

The Drosophila brain is composed of many morphologically and functionally distinct processing centers and brain morphogenesis depends on the creation and maintenance of distinct boundaries between adjacent regions to prevent cells from mixing. In the Drosophila visual system, I have found that Slit and Roundabout (Robo) proteins function to prevent cells from adjacent compartments from mixing. I have defined a boundary between two distinct compartments, the lamina and lobula, and find that the secreted ligand Slit is present in the lamina, while the Robo receptors (Robo, Robo2 and Robo3) are expressed on lobula neurons. I examined the function of theses proteins by identifying a tissue-specific allele of slit and creating transgenic RNAi flies that inhibit the expression of the Robo proteins. Loss of Slit or all three Robo proteins in the visual system results in the invasion of lobula neurons into the lamina. Mixing of cells at the lamina/lobula boundary results in glial cell mispositioning and aberrant photoreceptor axon targeting. Thus, Slit and Robo proteins are required to restrict movement of cells across the lamina/lobula boundary. Additionally, I have characterized Ptpmeg, a highly conserved protein tyrosine phosphatase (PTP). In addition to the C-terminus PTP domain, Ptpmeg contains a central PDZ domain and an N-terminus FERM domain. The in vivo role of this family of proteins is unknown. To explore the function of Ptpmeg in flies, mutants were generated by targeted gene disruption. Examination of the adult nervous system of Ptpmeg mutants reveals a defect in the mushroom bodies (MB), brain structures required for olfactory learning and memory. In mutant animals, the MB lobes are disorganized and fail to elaborate their characteristic structure. I find

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Biology.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Tayler, Timothy D., 1972-

Advisor dc:contributor.advisor

• Paul A. Garrity.

• Biology.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/28937
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/28937

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/28937