The actin cytoskeleton is required for maintenance of posterior pole plasm components in the Drosophila embryo

Lantz, Valerie; Clemens, Scott E; Miller, Ken

doi:10.1016/s0925-4773(99)00096-9

Cited by 41 publications

(31 citation statements)

References 39 publications

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“…Treatment of embryos with the actin-severing drugs Cytochalasin D and Latrunculin A disrupts the localization of oskar mRNA and protein, but not of bicoid mRNA (Lantz et al, 1999), which is similar to what we observed in lasp mutant embryos and consistent with a role of Lasp in actin-…”

Section: Discussionsupporting

confidence: 89%

“…oskar mRNA and protein remain tightly associated with the posterior pole during oogenesis and early embryogenesis, in spite of the strong cytoplasmic streaming that occurs after stage 10B of oogenesis (Gutzeit and Koppa, 1982), and experiments with the actin-severing drugs Cytochalasin D and Latrunculin A suggest that oskar mRNA and protein are attached to the actin cytoskeleton (Lantz et al, 1999). In addition, and in contrast to Oskar, Bicoid protein diffuses along the anteroposterior axis after its synthesis and is detected down to 30% of the egg length, although its mRNA is restricted to the anterior pole in the embryo [100-80% egg length (Driever and Nusslein-Volhard, 1988)], which suggests that mRNA localization is not sufficient for protein restriction.…”

Section: Introductionmentioning

confidence: 99%

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The actin-binding protein Lasp promotes Oskar accumulation at the posterior pole of theDrosophilaembryo

et al. 2009

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During Drosophila oogenesis, oskar mRNA is transported to the posterior pole of the oocyte, where it is locally translated and induces germ-plasm assembly. Oskar protein recruits all of the components necessary for the establishment of posterior embryonic structures and of the germline. Tight localization of Oskar is essential, as its ectopic expression causes severe patterning defects. Here, we show that the Drosophila homolog of mammalian Lasp1 protein, an actin-binding protein previously implicated in cell migration in vertebrate cell culture, contributes to the accumulation of Oskar protein at the posterior pole of the embryo. The reduced number of primordial germ cells in embryos derived from lasp mutant females can be rescued only with a form of Lasp that is capable of interacting with Oskar, revealing the physiological importance of the Lasp-Oskar interaction.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

The actin-binding protein Lasp promotes Oskar accumulation at the posterior pole of theDrosophilaembryo

et al. 2009

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“…Loss of LKB1 function in germ line clones of presumptive null alleles prevents the reorganization of the oocyte microtubule network at stage 7 that is required for posterior localization of osk mRNA and affects epithelial polarity in the ovarian follicle cells . LKB1 colocalizes with cortical actin in the oocyte, integrity of which is required for anchoring of pole plasm components and nos mRNA (Lantz et al 1999;Forrest and Gavis 2003). It is therefore attractive to speculate that LKB1 might act at the cortex, where actin and microtubule filaments meet, phosphorylating a currently unknown substrate to promote the trapping of pgc-containing RNPs.…”

Section: Discussionmentioning

confidence: 99%

The Molecular Chaperone Hsp90 Is Required for mRNA Localization in Drosophila melanogaster Embryos

et al. 2007

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Localization of maternal nanos mRNA to the posterior pole is essential for development of both the abdominal segments and primordial germ cells in the Drosophila embryo. Unlike maternal mRNAs such as bicoid and oskar that are localized by directed transport along microtubules, nanos is thought to be trapped as it swirls past the posterior pole during cytoplasmic streaming. Anchoring of nanos depends on integrity of the actin cytoskeleton and the pole plasm; other factors involved specifically in its localization have not been described to date. Here we use genetic approaches to show that the Hsp90 chaperone (encoded by Hsp83 in Drosophila) is a localization factor for two mRNAs, nanos and pgc. Other components of the pole plasm are localized normally when Hsp90 function is partially compromised, suggesting a specific role for the chaperone in localization of nanos and pgc mRNAs. Although the mechanism by which Hsp90 acts is unclear, we find that levels of the LKB1 kinase are reduced in Hsp83 mutant egg chambers and that localization of pgc (but not nos) is rescued upon overexpression of LKB1 in such mutants. These observations suggest that LKB1 is a primary Hsp90 target for pgc localization and that other Hsp90 partners mediate localization of nos.

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“…Scale bar: 100 µm. The PAR/aPKC complex and phosphoinositide signaling Wheatley et al, 1995;Tetzlaff et al, 1996;Lantz et al, 1999). Mutations in the gene shackleton also show defects in axial expansion and lack pole cells, but the posterior localization of oskar mRNA is normal, indicating that defects in axial expansion alone are sufficient to cause the lack of pole cells (Yohn et al, 2003).…”

Section: Pten Activity Is Required For the Control Of Several Actin Dmentioning

confidence: 99%

Direct association of Bazooka/PAR-3 with the lipid phosphatase PTEN reveals a link between the PAR/aPKC complex and phosphoinositide signaling

et al. 2005

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Cell polarity in Drosophila epithelia, oocytes and neuroblasts is controlled by the evolutionarily conserved PAR/aPKC complex, which consists of the serine-threonine protein kinase aPKC and the PDZ-domain proteins Bazooka(Baz) and PAR-6. The PAR/aPKC complex is required for the separation of apical and basolateral plasma membrane domains, for the asymmetric localization of cell fate determinants and for the proper orientation of the mitotic spindle. How the complex exerts these different functions is not known. We show that the lipid phosphatase PTEN directly binds to Baz in vitro and in vivo, and colocalizes with Baz in the apical cortex of epithelia and neuroblasts. PTEN is an important regulator of phosphoinositide turnover that antagonizes the activity of PI3-kinase. We show that Pten mutant ovaries and embryos lacking maternal and zygotic Pten function display phenotypes consistent with a function for PTEN in the organization of the actin cytoskeleton. In freshly laid eggs, the germ plasm determinants oskarmRNA and Vasa are not localized properly to the posterior cytocortex and pole cells do not form. In addition, the actin-dependent posterior movement of nuclei during early cleavage divisions does not occur and the synchrony of nuclear divisions at syncytial blastoderm stages is lost. Pten mutant embryos also show severe defects during cellularization. Our data provide evidence for a link between the PAR/aPKC complex, the actin cytoskeleton and PI3-kinase signaling mediated by PTEN.

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The actin cytoskeleton is required for maintenance of posterior pole plasm components in the Drosophila embryo

Cited by 41 publications

References 39 publications

The actin-binding protein Lasp promotes Oskar accumulation at the posterior pole of theDrosophilaembryo

The actin-binding protein Lasp promotes Oskar accumulation at the posterior pole of theDrosophilaembryo

The Molecular Chaperone Hsp90 Is Required for mRNA Localization in Drosophila melanogaster Embryos

Direct association of Bazooka/PAR-3 with the lipid phosphatase PTEN reveals a link between the PAR/aPKC complex and phosphoinositide signaling

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