PT  - JOURNAL ARTICLE
AU  - Durafshan Sakeena Syed
AU  - BM Swetha
AU  - O. Venkateswara Reddy
AU  - Heinrich Reichert
AU  - VijayRaghavan K.
TI  - Glial and neuronal Semaphorin signaling instruct the development of a functional myotopic map for <em>Drosophila</em> walking
AID  - 10.1101/027375
DP  - 2015 Jan 01
TA  - bioRxiv
PG  - 027375
4099  - http://biorxiv.org/content/early/2015/09/24/027375.short
4100  - http://biorxiv.org/content/early/2015/09/24/027375.full
AB  - 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 (Serna) 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.