Detection of calcium transients in Drosophila mushroom body neurons with camgaroo reporters.
Camgaroos are yellow fluorescent protein derivatives that hold promise as transgenically encoded calcium sensors in behaving animals. We expressed two versions of camgaroo in Drosophila mushroom bodies using the galactosidase-4 (GAL4) system. Potassium depolarization of brains expressing the reporters produces a robust increase in fluorescence that is blocked by removing extracellular calcium or by antagonists of voltage-dependent calcium channels. The fluorescence increase is not attributable to cytoplasmic alkalization; depolarization induces a slight acidification of the cytoplasm of mushroom body neurons. Acetylcholine applied near the dendrites of the mushroom body neurons induces a rapid and ipsilateral-specific fluorescence increase in the mushroom body axons that is blocked by antagonists of calcium channels or nicotinic acetylcholine receptors. Fluorescence was observed to increase in all three classes of mushroom body neurons, indicating that all types respond to cholinergic innervation.
Yu
Dinghui
D
Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Baird
Geoffrey S
GS
Tsien
Roger Y
RY
Davis
Ronald L
RL
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D004330:Drosophila / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D008164:Luminescent Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D024521:Mushroom Bodies / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D019076:Transgenes
D001426:Bacterial Proteins; D002121:Calcium Channel Blockers; D004268:DNA-Binding Proteins; C052130:GAL4 protein, S cerevisiae; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C054562:yellow fluorescent protein, Bacteria; D049452:Green Fluorescent Proteins; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium