scholarly journals Glial and neuronal Semaphorin signaling instruct the development of a functional myotopic map for Drosophila walking

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Durafshan Sakeena Syed ◽  
Swetha B.M. Gowda ◽  
O Venkateswara Reddy ◽  
Heinrich Reichert ◽  
K VijayRaghavan

Motoneurons developmentally acquire appropriate cellular architectures that ensure connections with postsynaptic muscles and presynaptic neurons. In Drosophila, leg motoneurons are organized as a myotopic map, where their dendritic domains represent the muscle field. Here, we investigate mechanisms underlying development of aspects of this myotopic map, required for walking. A behavioral screen identified roles for Semaphorins (Sema) and Plexins (Plex) in walking behavior. Deciphering this phenotype, we show that PlexA/Sema1a mediates motoneuron axon branching in ways that differ in the proximal femur and distal tibia, based on motoneuronal birth order. Importantly, we show a novel role for glia in positioning dendrites of specific motoneurons; PlexB/Sema2a is required for dendritic positioning of late-born motoneurons but not early-born motoneurons. These findings indicate that communication within motoneurons and between glia and motoneurons, mediated by the combined action of different Plexin/Semaphorin signaling systems, are required for the formation of a functional myotopic map.

2015 ◽  
Author(s):  
Durafshan Sakeena Syed ◽  
Swetha B.M. ◽  
O. Venkateswara Reddy ◽  
Heinrich Reichert ◽  
VijayRaghavan K.

Motoneurons developmentally acquire appropriate cellular architectures that ensure connections with postsynaptic muscles and presynaptic neurons. In Drosophila, leg motoneurons are organized as a myotopic map, where their dendritic domains represent the muscle field. Here we investigate mechanisms underlying development of aspects of this myotopic map, required for walking. A behavioral screen identified roles for Semaphorins (Sema) and Plexins (Plex) in walking behavior. Deciphering this phenotype, we show that PlexA/Sema1a mediates motoneuron axon branching in ways that differ in the proximal femur and distal tibia, based on motoneuronal birth order. Importantly, we show a novel role for glia in positioning dendrites of specific motoneurons; PlexB/Sema2a is required for dendritic positioning of late-born motoneurons but not early-born motoneurons. These findings indicate that communication within motoneurons and between glia and motoneurons, mediated by the combined action of different Plexin/Semaphorin signaling systems, are required for the formation of a functional myotopic map.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Reiner Wirbel ◽  
Frank Blümler ◽  
Dirk Lommel ◽  
Guido Syré ◽  
Veit Krenn

A 27-year-old man treated 2.5 years ago for synchronous multicentric giant cell tumor of bone located at the right proximal humerus and the right 5th finger presented now with complaints of pain in his right hip and wrist of two-month duration. Radiology and magnetic resonance revealed multicentric giant cell tumor lesions of the right proximal femur, the left ileum, the right distal radius, and the left distal tibia. The patient has an eighteen-year history of a healed osteosarcoma of the right tibia that was treated with chemotherapy, resection, and allograft reconstruction. A literature review establishes this as the first reported case of a patient with synchronous and metachronous multicentric giant cell tumor who also has a history of osteosarcoma.


2000 ◽  
Vol 55 (6) ◽  
pp. 599-612 ◽  
Author(s):  
Joseph Lee Rodgers ◽  
H. Harrington Cleveland ◽  
Edwin van den Oord ◽  
David C. Rowe
Keyword(s):  

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