In vivo analyses of cytoplasmic transport and cytoskeletal organization during Drosophila oogenesis: characterization of a multi-step anterior localization pathway.
Anterior patterning of the Drosophila embryo depends on localization of bicoid (bcd) mRNA to the anterior pole of the developing oocyte, and bcd mRNA localization requires both the exuperantia (exu) gene and an intact microtubule cytoskeleton. To gain insight into the mechanism of anterior patterning, we have used time lapse laser scanning confocal microscopy to analyze transport of particles containing a Green Fluorescent Protein-Exu fusion (GFP-Exu), and to directly image microtubule organization in vivo. Our observations indicate that microtubules are required for three forms of particle movement within the nurse cells, while transport through the ring canals linking the nurse cells and oocyte appears to be independent of both microtubules and actin filaments. As particles enter the oocyte, a final microtubule-dependent step directs movement to the oocyte cortex. However, our observations and previous studies suggest that the polarity of the oocyte microtubule network is not in itself sufficient to generate anterior asymmetry, and that additional factors are required to restrict morphogens to the anterior pole. Based on these observations, we propose a multi-step anterior localization pathway.
Theurkauf
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Department of Biochemistry and Cell Biology and the Institute for Cell and Developmental Biology, State University of New York at Stony Brook, Stony Brook, NY 11794-5215, USA.
Hazelrigg
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D000818:Animals; D001692:Biological Transport; D019521:Body Patterning / Q000235:genetics*; D003593:Cytoplasm / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D004330:Drosophila / Q000235:genetics / Q000254:growth & development; D029721:Drosophila Proteins; D004527:Egg Proteins / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000648:ultrastructure; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D009866:Oogenesis / Q000235:genetics / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
D029721:Drosophila Proteins; D004527:Egg Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D008164:Luminescent Proteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; C056478:bcd protein, Drosophila; C072067:exu protein, Drosophila; D049452:Green Fluorescent Proteins