title: Neuronal development in the Drosophila compound eye: photoreceptor cells R1, R6, and R7 fail to differentiate in the retina aberrant in pattern (rap) mutant.
abstract: The compound eye of Drosophila is a reiterated pattern of 800 unit eyes known as ommatidia. In each ommatidium there are eight photoreceptor neurons (R1-R8) and an invariant number of accessory cells organized in a precise manner. In the developing eye, specification of cell fates is triggered by sequential inductive events mediated by cell-cell interactions. The R8 photoreceptor neuron is the first cell to differentiate and is thought to play a central role in the recruitment of the remaining photoreceptor cells. Our previous work demonstrated that mutations in the retina aberrant in pattern (rap) locus lead to abnormal pattern formation in the compound eye. Genetic mosaic experiments demonstrated that for normal retinal patterning to occur, rap gene function is required only in the photoreceptor cell R8. In this study we analyzed the R cell composition of developing as well as the adult eyes of rap mutants employing a variety of R cell specific markers. We show that in rap mutants, although some of the R8-specific markers show normal expression patterns, other aspects of the R8 cell differentiation are abnormal. In addition, the cells R1, R6, and R7 fail to differentiate properly in rap mutants. These results suggest that the rap gene encodes an R8-specific function that plays a role in the determination of the photoreceptor cells R1, R6, and R7.
authors.affiliation: Department of Biology, City College, New York, New York 10031, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Karpilow
authors.forename: A C
authors.initials: AC
authors.lastname: Pimentel
authors.forename: H K
authors.initials: HK
authors.lastname: Shamloula
authors.forename: T R
authors.initials: TR
authors.lastname: Venkatesh
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D002450:Cell Communication / Q000502:physiology; D016923:Cell Death / Q000235:genetics; D002454:Cell Differentiation / Q000502:physiology; D003035:Cobalt; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D004742:Enhancer Elements, Genetic / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006023:Glycoproteins / Q000235:genetics*; D018398:Homeodomain Proteins; D007301:Insect Hormones / Q000235:genetics; D026563:LDL-Receptor Related Protein-Associated Protein; D007763:Lac Operon; D008024:Ligands; D008562:Membrane Glycoproteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D008854:Microscopy, Electron; D018832:Molecular Chaperones / Q000235:genetics; D009154:Mutation / Q000502:physiology; D009475:Neurons, Afferent / Q000166:cytology / Q000201:enzymology; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology / Q000196:embryology* / Q000648:ultrastructure; D011506:Proteins / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D018000:Receptors, Peptide; D011994:Recombinant Proteins / Q000235:genetics; D012160:Retina / Q000166:cytology / Q000196:embryology / Q000648:ultrastructure; D017299:Rod Opsins / Q000235:genetics; D013194:Staining and Labeling; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: C072318:B-H1 protein, Drosophila; D002352:Carrier Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D006023:Glycoproteins; D018398:Homeodomain Proteins; D007301:Insect Hormones; D026563:LDL-Receptor Related Protein-Associated Protein; D008024:Ligands; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D018832:Molecular Chaperones; D011506:Proteins; D018000:Receptors, Peptide; D011994:Recombinant Proteins; C081481:Rho protein, Drosophila; D017299:Rod Opsins; C472498:Stet protein, Drosophila; D014157:Transcription Factors; C072141:boss protein, Drosophila; C066579:sca protein, Drosophila; D003035:Cobalt; D020794:Receptor Protein-Tyrosine Kinases; C056737:sev protein, Drosophila; C027875:cobaltous sulfide