TY - JOUR
T1 - The Canoe protein is necessary in adherens junctions for development of ommatidial architecture in the Drosophila compound eye
AU - Matsuo, Takashi
AU - Takahashi, Kuniaki
AU - Suzuki, Emiko
AU - Yamamoto, Daisuke
PY - 1999/12/17
Y1 - 1999/12/17
N2 - Rhabdomeres of the Drosophila melanogaster canoe(misl) mutant ommatidia were twisted, branched, and often fused to each other. A considerable proportion of rhabdomeres were found to have fallen below the retinal basement membrane. Electron-microscopic observations of the mutant ommatidia revealed that microvilli, the subcellular structures composing the rhabdome, were normal. As was the case with partial loss-of-function mutations in the canoe locus, overexpression of the wild-type canoe transgene driven by the heat shock promoter or sevenless enhancer in the wild-type canoe background caused malformation of the rhabdomeres in the adult ommatidia. Immunolabeling of the Canoe protein in the pupal retinae showed that it was accumulated in adherens junctions in photoreceptor rhabdomeres at high concentrations, as well as in pigment cells, bristle cells, and the interjunctional region of photoreceptors at a lower level. In the canoe mutant ommatidia, the Canoe protein concentration was dramatically decreased in adherens junctions, while it was maintained at a level comparable with the wild-type flies in the interjunctional region. Since Canoe or its mammalian homolog AF-6 is known to bind to F-actin and Ras, we suggest the possibility that Canoe couples Ras signaling with cytoskeleton, thereby supporting the straight elongation of rhabdomere required for development of a regular array of ommatidia.
AB - Rhabdomeres of the Drosophila melanogaster canoe(misl) mutant ommatidia were twisted, branched, and often fused to each other. A considerable proportion of rhabdomeres were found to have fallen below the retinal basement membrane. Electron-microscopic observations of the mutant ommatidia revealed that microvilli, the subcellular structures composing the rhabdome, were normal. As was the case with partial loss-of-function mutations in the canoe locus, overexpression of the wild-type canoe transgene driven by the heat shock promoter or sevenless enhancer in the wild-type canoe background caused malformation of the rhabdomeres in the adult ommatidia. Immunolabeling of the Canoe protein in the pupal retinae showed that it was accumulated in adherens junctions in photoreceptor rhabdomeres at high concentrations, as well as in pigment cells, bristle cells, and the interjunctional region of photoreceptors at a lower level. In the canoe mutant ommatidia, the Canoe protein concentration was dramatically decreased in adherens junctions, while it was maintained at a level comparable with the wild-type flies in the interjunctional region. Since Canoe or its mammalian homolog AF-6 is known to bind to F-actin and Ras, we suggest the possibility that Canoe couples Ras signaling with cytoskeleton, thereby supporting the straight elongation of rhabdomere required for development of a regular array of ommatidia.
KW - Development
KW - Drosophila melanogaster (Insecta)
KW - Eye mutants
KW - PDZ-domain protein
KW - Photoreceptor
KW - Rhabdomere
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U2 - 10.1007/s004410050062
DO - 10.1007/s004410050062
M3 - Article
C2 - 10639730
AN - SCOPUS:0032705809
VL - 298
SP - 397
EP - 404
JO - Zeitschrift für Zellforschung und mikroskopische Anatomie (Vienna, Austria : 1948)
JF - Zeitschrift für Zellforschung und mikroskopische Anatomie (Vienna, Austria : 1948)
SN - 0302-766X
IS - 3
ER -