Drosophila Importin-α2 Is Involved in Synapse, Axon and Muscle Development

Abstract

Nuclear import is required for communication between the cytoplasm and the nucleus and to enact lasting changes in gene transcription following stimuli. Binding to an Importin-α molecule in the cytoplasm is often required to mediate nuclear entry of a signaling protein. As multiple isoforms of Importin-α exist, some may be responsible for the entry of distinct cargoes rather than general nuclear import. Indeed, in neuronal systems, Importin-α isoforms can mediate very specific processes such as axonal tiling and communication of an injury signal. To study nuclear import during development, we examined the expression and function of Importin-α2 in Drosophila melanogaster. We found that Importin-α2 was expressed in the nervous system where it was required for normal active zone density at the NMJ and axonal commissure formation in the central nervous system. Other aspects of synaptic morphology at the NMJ and the localization of other synaptic markers appeared normal in importin-α2 mutants. Importin-α2 also functioned in development of the body wall musculature. Mutants in importin-α2 exhibited errors in muscle patterning and organization that could be alleviated by restoring muscle expression of Importin-α2. Thus, Importin-α2 is needed for some processes in the development of both the nervous system and the larval musculature.

Drosophila Tet Is Expressed in Midline Glia and Is Required for Proper Axonal Development

“…Thirty brains were analyzed per genotype. Scoring was based on counting the number of segments at which axons diverge away from the midline (adapted from Mosca and Schwarz, 2010).…”

Retrograde neurotrophin signaling through Tollo regulates synaptic growth in Drosophila

“…Branch length was determined using ImageJ, where arbors of primary and secondary branches were measured starting at the first bouton or branch point after defasiculation (whichever occurred first). pJNK and puc-lacZ fluorescence intensity was measured using methods described previously ( Mosca and Schwarz, 2010a , b ). For pJNK analysis, confocal z stacks of distal and proximal boutons were imported into ImageJ and converted into multichannel composite images.…”

Neurodevelopmental Perspectives on Wnt Signaling in Psychiatry

“…Finally, in the Frizzled-nuclear import (FNI) pathway which thus far has only been described at the Drosophila melanogaster (fruit fly) neuromuscular junction [23,24,25], Wnt-Fzd binding causes internalization and cleavage of Fzd. Subsequent nuclear trafficking of a transcriptionally active Fzd cleavage fragment depends on its interaction with 7-PDZ-domain glutamate-receptor interacting protein (GRIP) [24,26].…”