Laserscanning Mikroskop mit Multiphotonen Laser
Final Report Abstract
The microscope has been used in four major projects from my lab. Project 1: This work focuses on insulin signaling in the brain. We show that insulin-producing cells project axons project to, and make direct contact, with the hugin neurons. Imp-L2, which biochemically interacts with insulin, is expressed in the hugin neurons and is required for increased insulin signaling in these neurons. We further show that starvation increases insulin signaling in the hugin neurons, demonstrating a difference between brain and periphery in response to nutrient signals. Project 2: We identified a cluster of four serotonergic neurons whose cell bodies are located in the brain and send their axons to the periphery to innervate the entire enteric nervous system. Using electrophysiological, GCaMP based calcium imaging and optogenetic techniques, we show that these likely respond to endocrine cues and function in foregut motility. Project 3: We have identified central neurons that modulate feeding motor patterns. In a multi-pronged approach, we showed that hugin neuropeptide cells can suppress pharyngeal pattern and induce locomotor pattern. Using RNAi, we show that hugin neuropeptide is required for this suppressive effect. Using promoter specific constructs, we separated the hugin neurons into distinct classes and show that distinct cluster modulate different behavioral components. Project 4: We are currently identifying the motor neurons that innervate the feeding muscles. We first express PA(photoactivatable)-GFP in glutamatergic neurons, as most known motor neurons are glutamatergic in Drosophila. We then activate the GFP in specific pharnygeal nerves with a two photon laser and trace it back to the brain. Having identified the motor neurons, we measure its rhythmic activity with GCaMP analysis. Manipulation of the glutamatergic neurons by optogenetics or thermal induced TrpA1 channel and monitoring behavioral complement this work.
Publications
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"The IGFBP7 homolog Imp-L2 promotes insulin signaling in distinct neurons of the Drosophila brain" (2013) J Cell Science 126, 2571
Bader R., Sarraf-Zadeh L., Peters M., Moderau N., Stocker H., Köhler K., Pankratz M. and Hafen E
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"Selection of motor programs for suppressing food intake and inducing locomotion in the Drosophila brain" (2014) PLoS Biol 12(6): e1001893
Schoofs A., Hückesfeld, S., Schlegel P., Miroschnikow A., Peters M., Zeymer M., Spieß R., Chiang A.S. and Pankratz M.
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"Serotongergic pathways in the Drosophila larval enteric nervous system". Journal of Insect Physiology, Volume 69, October 2014, Pages 118-125
Schoofs A., Hückesfeld S., Surendran S. and Pankratz M.
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"Src tyrosine kinase signaling antagonizes nuclear localization of FOXO and inhibits its transcription factor activity" (2014) Sci Rep. 4, 4048
Bülow M., Bülow T., Hoch M., Pankratz M. and Jünger M.
