Localization of choline acetyltransferase-expressing neurons in the larval visual system of Drosophila melanogaster.
Choline acetyltransferase (ChAT) is the enzyme catalyzing the biosynthesis of acetylcholine and is considered to be a phenotypically specific marker for cholinergic neurons. We have examined the distribution of ChAT-expressing neurons in the larval nervous system of Drosophila melanogaster by three different but complementary techniques: in situ hybridization with a cRNA probe to ChAT messenger RNA, immunocytochemistry using a monoclonal anti-ChAT antibody, and X-gal staining of transformed animals carrying a reporter gene composed of 7.4 kb of 5' flanking DNA from the ChAT gene fused to a lacZ reporter gene. All three techniques demonstrated ChAT-expressing neurons in the larval visual system. In embryos, the photoreceptor organ (Bolwig's organ) exhibited strong cRNA hybridization signals. The optic lobe of late third-instar larvae displayed ChAT immunoreactivity in Bolwig's nerve and a neuron close to the insertion site of the optic stalk. This neuron's axon ran in parallel with Bolwig's nerve to the larval optic neuropil. This neuron is likely to be a first-order interneuron of the larval visual system. Expression of the lacZ reporter gene was also detected in Bolwig's organ and the neuron stained by anti-ChAT antibody. Our observations indicate that acetylcholine may be a neurotransmitter in the larval photoreceptor cells as well as in a first-order interneuron in the larval visual system of Drosophila melanogaster.
Yasuyama
K
K
Division of Neurosciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
Kitamoto
T
T
Salvaterra
P M
PM
D000818:Animals; D000911:Antibodies, Monoclonal; D001921:Brain / Q000201:enzymology; D048429:Cell Size; D002795:Choline O-Acetyltransferase / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018076:DNA, Complementary; D004331:Drosophila melanogaster / Q000201:enzymology*; D004625:Embryo, Nonmammalian / Q000201:enzymology; D005697:Galactosides; D017930:Genes, Reporter; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007211:Indoles; D007763:Lac Operon; D007814:Larva / Q000201:enzymology; D009474:Neurons / Q000166:cytology / Q000201:enzymology*; D009899:Optic Lobe, Nonmammalian / Q000201:enzymology; D011679:Pupa / Q000201:enzymology; D012333:RNA, Messenger / Q000032:analysis; D014170:Transformation, Genetic; D014795:Visual Pathways / Q000502:physiology; D001616:beta-Galactosidase / Q000235:genetics
D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D005697:Galactosides; D007211:Indoles; D012333:RNA, Messenger; D002795:Choline O-Acetyltransferase; D001616:beta-Galactosidase; C044888:5-bromo-4-chloro-3-indolyl beta-galactoside