Panels A-C: The D42-Gal4 driver transgene conducting the expression of UAS-dPNA:GFP transgene in larval motor neurons. The confocal images show the motorneuron boutons loaded with dPNA:GFP, in dissected-fixed preparations. Arrowheads indicate the distribution of GFP puncta from the motor neuron presynapse to adjacent areas, most likely the skeletal muscles, supporting previous observations that dPNA:GFP can migrate from the presynapse to post-synaptic partners. Marking the terminal with an anti-Fasciclin-II MAb (Helt G. 1997*) for example, will help delineate the bouton-boundaries more accurately. Similarly, immunolabeling the muscles and colocalization will help confirm the anterograde dPNA:GFP transfer at the larval NMJ. Scale bar in A is approximately 8 microns.

Panels D-F: Expression of UAS-dPNA:GFP transgene by the dMEF2-Gal4 driver in the larval skeletal muscles (m). The filleted-preparations were immunlabled with an anti-BruchPilot (BRP) monoclonal antibody and AlexaFluor594 secondary antibody to localize the motor neuron presynaptic terminals. dPNA:GFP appears to migrate (arrow) from the post-synaptic muscle compartment to the segmental nerves innervating the muscle. GFP-puncta within the boutons (arrowheads) is almost absent. Is it the peripheral glial cells that ensheath the segmental nerves (but not the bouton terminals), that show preferential retrograde uptake of dPNA:GFP from the muscle? Colocalization of dPNA:GFP with a glia-specific marker, such as anti-gliotactin MAb (Auld et al. 1995), will be required to test this possibility.

*Helt, G. (1997) Data visualization and gene discovery in Drosophila melanogaster, Appendix A. PhD thesis, University of California at Berkeley.

Acknowledgements

Thanks to Drs. Milton Charlton, Jeffrey Dason (Dept. of Physiology, Univ. of Toronto) and Dr. Greg Macleod (Dept. of Physiology, UTHSCSA, San Antonio) for the support and discussions.

• confocal
• neuromuscular junction
• trans-synaptic transfer
• Peanut-Agglutinin
• motoneurons
• GFP
• gfp
• gfp
• Drosophila larva
• Drosophila
• drosophila
• drosophila
• skeletal muscles

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