An Egalitarian-BicaudalD complex is essential for oocyte specification and axis determination in Drosophila.

Mach, Jennifer; Lehmann, Ruth

doi:10.1101/gad.11.4.423

Cited by 190 publications

(235 citation statements)

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“…Within the ovary, the majority of studies have focused on the role of Egl in specification and maintenance of oocyte fate (Theurkauf et al 1993;Mach and Lehmann 1997;Huynh and St Johnston 2000;Bolivar et al 2001). The goal of the present study was to examine the function of Egl during midstages of egg chamber maturation.…”

Section: Resultsmentioning

confidence: 99%

“…Instead, egg chambers in these mutants contain 16 nurse cells (Theurkauf et al 1993;Carpenter 1994). Egl is thought to function in this pathway by restricting meiosis to a single cell and by promoting the microtubule-dependent transport of factors to the presumptive oocyte (Mach and Lehmann 1997;Huynh and St Johnston 2000;Bolivar et al 2001). Milder mutants in egl that are defective in binding Dynein light chain (Dlc) initially specify an oocyte.…”

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confidence: 99%

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Multiple Roles for Egalitarian in Polarization of the Drosophila Egg Chamber

et al. 2016

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The Drosophila egg chamber provides a useful model for examining mechanisms by which cell fates are specified and maintained in the context of a complex tissue. The egg chamber is also an excellent model for understanding the mechanism by which cytoskeletal filaments are organized and the critical interplay between cytoskeletal organization, polarity establishment, and cell fate specification. Previous work has shown that Egalitarian (Egl) is required for specification and maintenance of oocyte fate. Mutants in egl either completely fail to specify an oocyte, or if specified, the oocyte eventually reverts back to nurse cell fate. Due to this very early role for Egl in egg chamber maturation, it is unclear whether later stages of egg chamber development also require Egl function. In this report, we have depleted Egl at specific stages of egg chamber development. We demonstrate that in early-stage egg chambers, Egl has an additional role in organization of oocyte microtubules. In the absence of Egl function, oocyte microtubules completely fail to reorganize. As such, the localization of microtubule motors and their cargo is disrupted. In addition, Egl also appears to function in regulating the translation of critical polarity determining messenger RNAs (mRNAs). Finally, we demonstrate that in midstage egg chambers, Egl does not appear to be required for microtubule organization, but rather for the correct spatial localization of oskar, bicoid, and gurken mRNAs.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Multiple Roles for Egalitarian in Polarization of the Drosophila Egg Chamber

et al. 2016

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“…BicD1 is the human homolog of the Drosophila Bicaudal D gene (BICD). BICD was originally identified as a developmental gene associated with mRNA and Golgi-endoplasmic reticulum transport in Drosophila and mammalian cells (22)(23)(24)(25)(26). We found that endogenous BicD1 strongly interacts with the C-terminal cytoplasmic domain of PAR1, which inhibits signaling to G q -PLC-␤ pathways.…”

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confidence: 91%

A Novel Protease-activated Receptor-1 Interactor, Bicaudal D1, Regulates G Protein Signaling and Internalization

Swift

Trivedi

et al. 2010

Journal of Biological Chemistry

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Protease-activated receptor-1 (PAR1) is a G protein-coupled receptor that plays critical roles in cancer, angiogenesis, inflammation, and thrombosis. Proteolytic cleavage of the extracellular domain of PAR1 generates a tethered ligand that activates PAR1 in an unusual intramolecular mode. The signal emanating from the irreversibly cleaved PAR1 is terminated by G protein uncoupling and internalization; however, the mechanisms of PAR1 signal shut off still remain unclear. Using a yeast twohybrid screen, we identified Bicaudal D1 (BicD1) as a direct interactor with the C-terminal cytoplasmic domain of PAR1. BICD was originally identified as an essential developmental gene associated with mRNA and Golgi-endoplasmic reticulum transport. We discovered a novel function of BicD1 in the modulation of G protein signaling, cell proliferation, and endocytosis downstream of PAR1. BicD1 and its C-terminal CC3 domain inhibited PAR1 signaling to G q -phospholipase C-␤ through coiled-coil interactions with the cytoplasmic 8th helix of PAR1. Unexpectedly, BicD1 was also found to be a potent suppressor of PAR1-driven proliferation of breast carcinoma cells. The growth-suppressing effects of BicD1 required the ability to interact with the 8th helix of PAR1. Silencing of BicD1 expression impaired endocytosis of PAR1, and BicD1 co-localized with PAR1 and tubulin, implicating BicD1 as an important adapter protein involved in the transport of PAR1 from the plasma membrane to endosomal vesicles. Together, these findings provide a link between PAR1 signal termination and internalization through the non-G protein effector, BicD1.

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“…Other genes encoding DE-cadherin (DE-cad) and Armadillo (Arm) determine the oocyte positioning through direct regulation of the adhesion of the oocyte to the follicle cells at the posterior of the egg chamber [13,14]. To test whether these are affected in lgl mutants, we generated germline clones homozygous for lgl 4 and examined the expression of oocyte specification markers Orb, Dynein heavy chain 64C (DHC64C) and Egalitarian (Egl) in the germarium [36,44,45]. Similar to the wild type, all these proteins mainly accumulated in the oocyte in germarial region 3 ( Figure 4A-4C, data not shown), implying that Lgl plays no direct role in oocyte differentiation.…”

Section: Lgl Is Required For the Stalk Cell Differentiation Linked Tomentioning

confidence: 99%

“…The following primary antibodies were used in this work: mouse anti-Orb (1:200, DSHB 6H4), rabbit anti-Bib (1:2 000, gift from YN Jan) [42], mouse anti-β-Gal (1:10, DSHB 40-1a), mouse anti-DHC64C (1:100, gift from TS Hays) [58], rabbit anti-Egl (1:4000, gift from R Lehmann) [45], mouse anti-Arm (1:200, DSHB N2 7A1), rat anti-DE-cad (1:200, DSHB DCAD2), rat anti-Stau (1:1 000, gift from Anne Ephrussi), rabbit anti-Osk (1:3 000, gift from A. Ephrussi) [48], mouse anti-Grk (1:200, DSHB 1D12), and mouse anti-Fas3 (1:200, DSHB 7G10). Secondary antibodies conjugated with Alexa Fluor 488, 546, 568 or 647 (Molecular Probes) were used at 1:1 000 dilution.…”

Section: Antibodies and Immunofluorescencementioning

confidence: 99%

Lethal(2)giant larvae is required in the follicle cells for formation of the initial AP asymmetry and the oocyte polarity during Drosophila oogenesis

Xin

Chen

et al. 2008

Cell Res

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The intricately regulated differentiation of the somatic follicle cell lineages into distinct subpopulations with specific functions plays an essential role in Drosophila egg development. At early oogenesis, induction of the stalk cells generates the first anteroposterior (AP) asymmetry in the egg chamber by inducing the posterior localization of the oocyte. Later, the properly specified posterior follicle cells signal to polarize the oocyte along the AP and dorsoventral (DV) axes at mid-oogenesis. Here, we show that lethal(2)giant larvae (lgl), a Drosophila tumor suppressor gene, is required in the follicle cells for the differentiation of both stalk cells and posterior follicle cells. Loss-of-function mutations in lgl cause oocyte mispositioning in the younger one of the fused chambers, due to lack of the stalk. Removal of lgl function from the posterior follicle cells using the FLP/FRT system results in loss of the oocyte polarity that is elicited by the failure of those posterior cells to differentiate normally. Thus, we provide the first demonstration that lgl is implicated in the formation of the initial AP asymmetry and the patterning of the AP and DV axes in the oocyte by acting in the specification of a subset of somatic follicle cells.

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An Egalitarian-BicaudalD complex is essential for oocyte specification and axis determination in Drosophila.

Cited by 190 publications

References 46 publications

Multiple Roles for Egalitarian in Polarization of the Drosophila Egg Chamber

Multiple Roles for Egalitarian in Polarization of the Drosophila Egg Chamber

A Novel Protease-activated Receptor-1 Interactor, Bicaudal D1, Regulates G Protein Signaling and Internalization

Lethal(2)giant larvae is required in the follicle cells for formation of the initial AP asymmetry and the oocyte polarity during Drosophila oogenesis

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