Actin Organization in the Early Drosophila Embryo

2008 ◽  
pp. 127-143 ◽  
Author(s):  
Eyal D. Schejter
Keyword(s):  
Drosophila Embryo ◽  
Actin Organization ◽  
Early Drosophila Embryo

scholarly journals The Concentration of Nuf, a Rab11 Effector, at the Microtubule-organizing Center Is Cell Cycle–regulated, Dynein-dependent, and Coincides with Furrow Formation

2007 ◽  
Vol 18 (9) ◽  
pp. 3313-3322 ◽  
Author(s):  
Blake Riggs ◽  
Barbara Fasulo ◽  
Anne Royou ◽  
Sarah Mische ◽  
Jian Cao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Small Gtpase ◽  
Drosophila Embryo ◽  
Microtubule Organizing Center ◽  
Recycling Endosome ◽  
Actin Organization ◽  
Protein Levels ◽  
Nuclear Fallout ◽  
Early Drosophila Embryo ◽  
Organizing Center

Animal cytokinesis relies on membrane addition as well as acto-myosin–based constriction. Recycling endosome (RE)-derived vesicles are a key source of this membrane. Rab11, a small GTPase associated with the RE and involved in vesicle targeting, is required for elongation of the cytokinetic furrow. In the early Drosophila embryo, Nuclear-fallout (Nuf), a Rab11 effector, promotes vesicle-mediated membrane delivery and actin organization at the invaginating furrow. Although Rab11 maintains a relatively constant localization at the microtubule-organizing center (MTOC), Nuf is present at the MTOC only during the phases of the cell cycle in which furrow invagination occurs. We demonstrate that Nuf protein levels remain relatively constant throughout the cell cycle, suggesting that Nuf is undergoing cycles of concentration and dispersion from the MTOC. Microtubules, but not microfilaments, are required for proper MTOC localization of Nuf and Rab11. The MTOC localization of Nuf also relies on Dynein. Immunoprecipitation experiments demonstrate that Nuf and Dynein physically interact. In accord with these findings, and in contrast to previous reports, we demonstrate that microtubules are required for proper metaphase furrow formation. We propose that the cell cycle–regulated, Dynein-dependent recruitment of Nuf to the MTOC influences the timing of RE-based vesicle delivery to the invaginating furrows.

The Cytoskeleton of the Early Drosophila Embryo

1986 ◽  
Vol 1986 (Supplement 5) ◽  
pp. 311-328 ◽  
Author(s):  
R. M. WARN
Keyword(s):  
Drosophila Embryo ◽  
Early Drosophila Embryo

scholarly journals Assembly of yolk spindles in the early Drosophila embryo

2003 ◽  
Vol 120 (4) ◽  
pp. 441-454 ◽  
Author(s):  
Maria Giovanna Riparbelli ◽  
Giuliano Callaini
Keyword(s):  
Drosophila Embryo ◽  
Early Drosophila Embryo

The distribution of cytoplasmic bacteria in the early Drosophila embryo is mediated by astral microtubules

1994 ◽  
Vol 107 (3) ◽  
pp. 673-682 ◽  
Author(s):  
G. Callaini ◽  
M.G. Riparbelli ◽  
R. Dallai
Keyword(s):  
Cortical Layer ◽  
Drosophila Embryo ◽  
Mitotic Spindles ◽  
Embryo Viability ◽  
Polar Bodies ◽  
Early Drosophila Embryo ◽  
Close Relationship ◽  
Different Strains ◽  
Partial Dissociation ◽  
Almost All

Maternally inherited cytoplasmic bacteria have occasionally been observed in embryos and adults of different strains of several Drosophila species. While there is a considerable body of data on the relationship between bacteria and embryo viability, little is known about the behavior of these bacteria during the early development of Drosophila. In eggs laid by infected Drosophila melanogaster females we showed that cytoplasmic bacteria were initially concentrated in a thin cortical layer and scattered in the yolk region. During the following syncytial blastoderm mitoses the bacteria mainly accumulated towards the poles of the mitotic spindles, suggesting that astral microtubules play a role in localizing bacteria. This is supported by the observation that treatment of the infected embryos with the microtubule-disrupting drug colchicine led to the partial dissociation of the bacteria from the spindle poles, whereas cytochalasin treatment left almost all the bacterial clusters intact. Moreover, bacteria were not found near the polar bodies and yolk nuclei, which were without astral microtubules. In mitosis-defective embryos, with centrosomes dissociated from the nuclei, the bacteria were concentrated in association with the isolated astral microtubules, and in cold-treated embryos, in which microtubules regrew from isolated centrosomes after recovering, the bacteria clustered around the newly formed asters. These observations, also supported by electron microscope analysis, indicate a close relationship between cytoplasmic bacteria and astral microtubules, and suggest that the latter were able to build discrete cytoplasmic domains ensuring the proper distribution of cytoplasmic components during the blastoderm mitoses, despite the lack of cell membranes.

scholarly journals Evolution of maternal and zygotic mRNA complements in the early Drosophila embryo

PLoS Genetics ◽  
2018 ◽  
Vol 14 (12) ◽  
pp. e1007838 ◽  
Author(s):  
Joel Atallah ◽  
Susan E. Lott
Keyword(s):  
Drosophila Embryo ◽  
Early Drosophila Embryo

scholarly journals The GAGA factor is required in the early Drosophila embryo not only for transcriptional regulation but also for nuclear division

Development ◽  
1996 ◽  
Vol 122 (4) ◽  
pp. 1113-1124 ◽  
Author(s):  
K.M. Bhat ◽  
G. Farkas ◽  
F. Karch ◽  
H. Gyurkovics ◽  
J. Gausz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chromatin Remodeling ◽  
In Vitro Transcription ◽  
Drosophila Embryo ◽  
Gaga Factor ◽  
Early Drosophila Embryo ◽  
Hypersensitive Sites ◽  
And Function ◽  
Stimulatory Factor

The GAGA protein of Drosophila was first identified as a stimulatory factor in in vitro transcription assays using the engrailed and Ultrabithorax promoters. Subsequent studies have suggested that the GAGA factor promotes transcription by blocking the repressive effects of histones; moreover, it has been shown to function in chromatin remodeling, acting together with other factors in the formation of nuclease hypersensitive sites in vitro. The GAGA factor is encoded by the Trithorax-like locus and in the studies reported here we have used the maternal effect allele Trl13C to examine the functions of the protein during embryogenesis. We find that GAGA is required for the proper expression of a variety of developmental loci that contain GAGA binding sites in their upstream regulatory regions. The observed disruptions in gene expression are consistent with those expected for a factor involved in chromatin remodeling. In addition to facilitating gene expression, the GAGA factor appears to have a more global role in chromosome structure and function. This is suggested by the spectrum of nuclear cleavage cycle defects observed in Trl13C embryos. These defects include asynchrony in the cleavage cycles, failure in chromosome condensation, abnormal chromosome segregation and chromosome fragmentation. These defects are likely to be related to the association of the GAGA protein with heterochromatic satellite sequences which is observed throughout the cell cycle.

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