Highwire coordinates synapse formation and maturation by regulating both a map kinase cascade and the ability of the axon to respond to external cues in the giant fiber system of Drosophila Melanogaster

• Other Authors: Borgen, Melissa A. (author)
• Format: Others
• Language: English
• Published: Florida Atlantic University
• Subjects: Cell differentiation; Cellular control mechanisms; Cellular signal transduction; Drosophila melanogaster > Cytogenetics; Gene expression; Genetic transcription
• Online Access: http://purl.flvc.org/fau/fd/FA00004081; http://purl.flvc.org/fau/fd/FA00004081

The ubiquitin ligase Highwire is responsible for cell-autonomously promoting synapse formation in the Drosophila Giant Fiber system. highwire mutants show defects in synaptic function and extra branching at the axon terminal, corresponding to transient branching that occur in the course of giant synapse formation during metamorphosis. The MAP kinase pathway, including Wallenda and JNK/Basket, plus the transcription factor Jun, act to suppress synaptic function and axon pruning in a dosage sensitive manner, suggesting different molecular mechanisms downstream of the MAP kinase pathway govern function and pruning. A novel role for Highwire is revealed, regulating the giant fiber axon’s ability to respond to external cues regulated by Fos. When expression of the transcription factor Fos is disrupted in the post-synaptic TTMn or surrounding midline glia of highwire mutants, the giant fiber axons show a marked increase in axon overgrowth and midline crossing. However, synaptic function is rescued by the cell nonautonomous manipulation of Fos, indicating distinct mechanisms downstream of Highwire regulating synaptic function and axon morphology. === Includes bibliography. === Dissertation (Ph.D.)--Florida Atlantic University, 2014. === FAU Electronic Theses and Dissertations Collection