RRC ID 5665
Author Erclik T, Hartenstein V, Lipshitz HD, McInnes RR.
Title Conserved role of the Vsx genes supports a monophyletic origin for bilaterian visual systems.
Journal Curr Biol
Abstract BACKGROUND:Components of the genetic network specifying eye development are conserved from flies to humans, but homologies between individual neuronal cell types have been difficult to identify. In the vertebrate retina, the homeodomain-containing transcription factor Chx10 is required for both progenitor cell proliferation and the development of the bipolar interneurons, which transmit visual signals from photoreceptors to ganglion cells.
RESULTS:We show that dVsx1 and dVsx2, the two Drosophila homologs of Chx10, play a conserved role in visual-system development. DVSX1 is expressed in optic-lobe progenitor cells, and, in dVsx1 mutants, progenitor cell proliferation is defective, leading to hypocellularity. Subsequently, DVSX1 and DVSX2 are coexpressed in a subset of neurons in the medulla, including the transmedullary neurons that transmit visual information from photoreceptors to deeper layers of the visual system. In dVsx mutant adults, the optic lobe is reduced in size, and the medulla is small or absent. These results suggest that the progenitor cells and photoreceptor target neurons of the vertebrate retina and fly optic lobe are ancestrally related. Genetic and functional homology may extend to the neurons directly downstream of the bipolar and transmedullary neurons, the vertebrate ganglion cells and fly lobula projection neurons. Both cell types project to visual-processing centers in the brain, and both sequentially express the Math5/ATO and Brn3b/ACJ6 transcription factors during their development.
CONCLUSIONS:Our findings support a monophyletic origin for the bilaterian visual system in which the last common ancestor of flies and vertebrates already contained a primordial visual system with photoreceptors, interneurons, and projection neurons.
Volume 18(17)
Pages 1278-87
Published 2008-9-9
DOI 10.1016/j.cub.2008.07.076
PII S0960-9822(08)01021-X
PMID 18723351
MeSH Animals Cell Differentiation / genetics Cell Proliferation Drosophila / cytology Drosophila / embryology Drosophila / genetics* Embryo, Nonmammalian / chemistry Embryo, Nonmammalian / cytology Embryo, Nonmammalian / metabolism Embryonic Development / genetics Eye / embryology Larva / chemistry Larva / cytology Larva / genetics Mutation Nerve Tissue Proteins / analysis Nerve Tissue Proteins / genetics Nerve Tissue Proteins / physiology* Neuroepithelial Cells / chemistry Neuroepithelial Cells / cytology Neuroepithelial Cells / metabolism Optic Lobe, Nonmammalian / chemistry Optic Lobe, Nonmammalian / cytology Optic Lobe, Nonmammalian / embryology Photoreceptor Cells, Invertebrate / metabolism Phylogeny Retina / metabolism Sequence Homology, Amino Acid Stem Cells / chemistry Stem Cells / cytology Stem Cells / metabolism Transcription Factors / chemistry Transcription Factors / genetics Transcription Factors / physiology Vision, Ocular / genetics*
IF 9.601
Times Cited 29
Drosophila DGRC#105481