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Hugh R. Woodland - One of the best experts on this subject based on the ideXlab platform.
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Protein Interactions in Xenopus Germ Plasm RNP Particles
PloS one, 2013Co-Authors: Sarbjit Nijjar, Hugh R. WoodlandAbstract:Hermes is an RNA-binding protein that we have previously reported to be found in the ribonucleoprotein (RNP) particles of Xenopus Germ Plasm, where it is associated with various RNAs, including that encoding the Germ line determinant Nanos1. To further define the composition of these RNPs, we performed a screen for Hermes-binding partners using the yeast two-hybrid system. We have identified and validated four proteins that interact with Hermes in Germ Plasm: two isoforms of Xvelo1 (a homologue of zebrafish Bucky ball) and Rbm24b and Rbm42b, both RNA-binding proteins containing the RRM motif. GFP-Xvelo fusion proteins and their endogenous counterparts, identified with antisera, were found to localize with Hermes in the Germ Plasm particles of large oocytes and eggs. Only the larger Xvelo isoform was naturally found in the Balbiani body of previtellogenic oocytes. Bimolecular fluorescence complementation (BiFC) experiments confirmed that Hermes and the Xvelo variants interact in Germ Plasm, as do Rbm24b and 42b. Depletion of the shorter Xvelo variant with antisense oligonucleotides caused a decrease in the size of Germ Plasm aggregates and loosening of associated mitochondria from these structures. This suggests that the short Xvelo variant, or less likely its RNA, has a role in organizing and maintaining the integrity of Germ Plasm in Xenopus oocytes. While GFP fusion proteins for Rbm24b and 42b did not localize into Germ Plasm as specifically as Hermes or Xvelo, BiFC analysis indicated that both interact with Hermes in Germ Plasm RNPs. They are very stable in the face of RNA depletion, but additive effects of combinations of antisense oligos suggest they may have a role in Germ Plasm structure and may influence the ability of Hermes protein to effectively enter RNP particles.
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Localisation of RNAs into the Germ Plasm of Vitellogenic Xenopus Oocytes
PLoS ONE, 2013Co-Authors: Sarbjit Nijjar, Hugh R. WoodlandAbstract:We have studied the localisation of mRNAs in full-grown Xenopus laevis oocytes by injecting fluorescent RNAs, followed by confocal microscopy of the oocyte cortex. Concentrating on RNA encoding the Xenopus Nanos homologue, nanos1 (formerly Xcat2), we find that it consistently localised into aggregated Germ Plasm ribonucleoprotein (RNP) particles, independently of cytoskeletal integrity. This implies that a diffusion/entrapment-mediated mechanism is active, as previously reported for previtellogenic oocytes. Sometimes this was accompanied by localisation into scattered particles of the "late", Vg1/VegT pathway; occasionally only late pathway localisation was seen. The Xpat RNA behaved in an identical fashion and for neither RNA was the localisation changed by any culture conditions tested. The identity of the labelled RNP aggregates as definitive Germ Plasm was confirmed by their inclusion of abundant mitochondria and co-localisation with the Germ Plasm protein Hermes. Further, the nanos1/Hermes RNP particles are interspersed with those containing the Germ Plasm protein Xpat. These aggregates may be followed into the Germ Plasm of unfertilized eggs, but with a notable reduction in its quantity, both in terms of injected molecules and endogenous structures. Our results conflict with previous reports that there is no RNA localisation in large oocytes, and that during mid-oogenesis even Germ Plasm RNAs localise exclusively by the late pathway. We find that in mid oogenesis nanos1 RNA also localises to Germ Plasm but also by the late pathway. Late pathway RNAs, Vg1 and VegT, also may localise into Germ Plasm. Our results support the view that mechanistically the two modes of localisation are extremely similar, and that in an injection experiment RNAs might utilise either pathway, the distinction in fates being very subtle and subject to variation. We discuss these results in relation to their biological significance and the results of others.
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The Protein Encoded by the Germ Plasm RNA Germes Associates With Dynein Light Chains and Functions in Xenopus Germline Development
Differentiation; research in biological diversity, 2007Co-Authors: Lyubov A. Berekelya, Hugh R. Woodland, Maxim B. Ponomarev, Natalia N. Luchinskaya, Alexander A. Mikryukov, A. V. BelyavskyAbstract:Germ Plasm plays a prominent role in Germline formation in a large number of animal taxons. We previously identified a novel maternal RNA named Germes associated with Xenopus Germ Plasm. In the present work, we addressed possible involvement of Germes protein in Germ Plasm function. Expression in oocytes followed by confocal microscopy revealed that the EGFP fused to Germes, in contrast to the free EGFP, co-localized with the Germ Plasm. Overexpression of intact Germes and Germes lacking both leucine zipper motifs (GermesDeltaLZs) resulted in a statistically significant reduction of the number of primordial Germ cells (PGCs). Furthermore, the GermesDeltaLZs mutant inhibited PGC migration and produced abnormalities in Germ Plasm intra-cellular distribution at tailbud stages. To begin unraveling biochemical interactions of Germes during embryogenesis, we searched for Germes partners using yeast two-hybrid (YTH) system. Two closely related sequences were identified, encoding Xenopus dynein light chains dlc8a and dlc8b. Tagged versions of Germes and dlc8s co-localize in VERO cells upon transient expression and can be co-immunoprecipitated after injection of the corresponding RNAs in Xenopus embryos, indicating that their interactions occur in vivo. We conclude that Germes is involved in organization and functioning of Germ Plasm in Xenopus, probably through interaction with motor complexes.
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Xenopus Xpat protein is a major component of Germ Plasm and may function in its organisation and positioning.
Developmental biology, 2005Co-Authors: Rachel J. Machado, Mary Lou King, Wendy Moore, Richard Hames, Evelyn Houliston, Patrick Chang, Hugh R. WoodlandAbstract:Abstract In many animals, including Drosophila, C. elegans, zebrafish and Xenopus, the Germ line is specified by maternal determinants localised in a distinct cytoPlasmic structure called the Germ Plasm. This is consists of dense granules, mitochondria, and specific localised RNAs. We have characterised the expression and properties of the protein encoded by Xpat, an RNA localised to the Germ Plasm of Xenopus. Immunofluorescence and immunoblotting showed that this novel protein is itself a major constituent of Germ Plasm throughout oogenesis and early development, although it is also present in other regions of oocytes and embryos, including their nuclei. We found that an Xpat-GFP fusion protein can localise correctly in cultured oocytes, in early oocytes to the ‘mitochondrial cloud’, from which Germ Plasm originates, and in later oocytes to the vegetal cortex. The localisation process was microtubule-dependent, while cortical anchoring required microfilaments. Xpat-GFP expressed in late stage oocytes assembled into circular fields of multi-particulate structures resembling endogenous fields of Germ Plasm islands. Furthermore these structures could be induced to form at ectopic sites by manipulation of culture conditions. Ectopic Xpat-GFP islands were able to recruit mitochondria, a major Germ Plasm component. These data suggest that Xpat protein has an important role in Xenopus Germ Plasm formation, positioning and maintenance.
Denhi Schnabel - One of the best experts on this subject based on the ideXlab platform.
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Applying Rho Pathway Inhibitors to Investigate Germ Plasm Localization.
Methods in molecular biology (Clifton N.J.), 2021Co-Authors: Jerónimo Miranda, Denhi SchnabelAbstract:The correct assembly, migration, and segregation of the mRNAs of the Germ Plasm during the first cell divisions are intimately connected to the cytoskeleton and cytokinesis.RhoA is a key regulator of Germ Plasm localization during the first two cell division cycles in zebrafish embryos. Pharmacological inhibition of RhoA and his effector ROCK affected the correct assembly of microtubules in the cleavage furrow with the concomitant abnormal localization of Germ Plasm mRNAs. The inhibition of RhoA/ROCK pathway caused a significant decrease in the Germ cell population later in development.
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rhoa rock pathway activity is essential for the correct localization of the Germ Plasm mrnas in zebrafish embryos
Developmental Biology, 2017Co-Authors: Jeronimo Roberto Mirandarodriguez, Mario Zurita, Hilda Lomelí, Enrique Salasvidal, Denhi SchnabelAbstract:Zebrafish Germ Plasm is composed of mRNAs such as vasa and nanos and of proteins such as Bucky ball, all of which localize symmetrically in four aggregates at the distal region of the first two cleavage furrows. The coordination of actin microfilaments, microtubules and kinesin is essential for the correct localization of the Germ Plasm. Rho-GTPases, through their effectors, coordinate cytoskeletal dynamics. We address the participation of RhoA and its effector ROCK in Germ Plasm localization during the transition from two- to eight-cell embryos. We found that active RhoA is enriched along the cleavage furrow during the first two division cycles, whereas ROCK localizes at the distal region of the cleavage furrows in a similar pattern as the Germ Plasm mRNAs. Specific inhibition of RhoA and ROCK affected microtubules organization at the cleavage furrow; these caused the incorrect localization of the Germ Plasm mRNAs. The incorrect localization of the Germ Plasm led to a dramatic change in the number of Germ cells during the blastula and 24hpf embryo stages without affecting any other developmental processes. We demonstrate that the Rho/ROCK pathway is intimately related to the determination of Germ cells in zebrafish embryos.
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RhoA/ROCK pathway activity is essential for the correct localization of the Germ Plasm mRNAs in zebrafish embryos.
Developmental biology, 2016Co-Authors: Jerónimo Roberto Miranda-rodríguez, Enrique Salas-vidal, Hilda Lomelí, Mario Zurita, Denhi SchnabelAbstract:Zebrafish Germ Plasm is composed of mRNAs such as vasa and nanos and of proteins such as Bucky ball, all of which localize symmetrically in four aggregates at the distal region of the first two cleavage furrows. The coordination of actin microfilaments, microtubules and kinesin is essential for the correct localization of the Germ Plasm. Rho-GTPases, through their effectors, coordinate cytoskeletal dynamics. We address the participation of RhoA and its effector ROCK in Germ Plasm localization during the transition from two- to eight-cell embryos. We found that active RhoA is enriched along the cleavage furrow during the first two division cycles, whereas ROCK localizes at the distal region of the cleavage furrows in a similar pattern as the Germ Plasm mRNAs. Specific inhibition of RhoA and ROCK affected microtubules organization at the cleavage furrow; these caused the incorrect localization of the Germ Plasm mRNAs. The incorrect localization of the Germ Plasm led to a dramatic change in the number of Germ cells during the blastula and 24hpf embryo stages without affecting any other developmental processes. We demonstrate that the Rho/ROCK pathway is intimately related to the determination of Germ cells in zebrafish embryos.
Francisco Pelegri - One of the best experts on this subject based on the ideXlab platform.
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The role of the cytoskeleton in Germ Plasm aggregation and compaction in the zebrafish embryo.
Current topics in developmental biology, 2020Co-Authors: Cara E Moravec, Francisco PelegriAbstract:The transmission of genetic information from one generation to another is crucial for survival of animal species. This is accomplished by the induction of primordial Germ cells (PGCs) that will eventually establish the Germline. In some animals the Germline is induced by signals in gastrula, whereas in others it is specified by inheritance of maternal determinants, known as Germ Plasm. In zebrafish, aggregation and compaction of maternally derived Germ Plasm during the first several embryonic cell cycles is essential for generation of PGCs. These processes are controlled by cellular functions associated with the cellular division apparatus. Ribonucleoparticles containing Germ Plasm components are bound to both the ends of astral microtubules and a dynamic F-actin network through a mechanism integrated with that which drives the cell division program. In this chapter we discuss the role that modifications of the cell division apparatus, including the cytoskeleton and cytoskeleton-associated proteins, play in the regulation of zebrafish Germ Plasm assembly.
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Aggregation, segregation, and dispersal of homotypic Germ Plasm RNPs in the early zebrafish embryo
Developmental dynamics : an official publication of the American Association of Anatomists, 2019Co-Authors: Celeste Eno, Christina L. Hansen, Francisco PelegriAbstract:Background In zebrafish and many other organisms, specification of primordial Germ cells (PGCs) requires the transmission of maternally-derived Germ Plasm. Zebrafish Germ Plasm ribonucleoparticles (RNPs) aggregate along the cleavage furrows during the first several cell cycles, segregate asymmetrically during the cleavage stages, and undergo cytoPlasmic dispersal in the late blastula. Results For all tested Germ Plasm RNAs [carbonic anhydrase 15b (ca15b), deleted in azoospermia-like (dazl), dead end (dnd), nanos 3 (nos3), regulator of G-protein signaling14a (rgs14a), and vasa/DEAD box polypeptide 4 (vasa/ddx4)], RNPs are homotypic (containing a single RNA type), with RNPs packing tightly yet remaining distinct within Germ Plasm aggregates. Homotypic clustering of RNAs within RNPs is observed before aggregation in the cortex and is maintained through Germ Plasm recruitment, asymmetric segregation and RNP dispersal. We also identify a step of Germ Plasm fragmentation during the cleavage stages that precedes RNP dispersal. Conclusions Our findings suggest that Germ Plasm aggregates act as subcellular compartments that temporarily collect and carry single RNA-type RNPs from fertilization until their cytoPlasmic dispersal in PGCs at the end of the blastula period, and describe a previously unknown fragmentation step that allows for an increase in the pool of Germ Plasm-carrying cells, presumably PGCs. Developmental Dynamics 248:306-318, 2019. © 2019 Wiley Periodicals, Inc.
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Modulation of F-actin dynamics by maternal Mid1ip1L controls Germ Plasm aggregation and furrow recruitment in the zebrafish embryo.
Development (Cambridge England), 2018Co-Authors: Celeste Eno, Francisco PelegriAbstract:ABSTRACT During the early embryonic cell cycles, zebrafish Germ Plasm ribonucleoparticles (RNPs) gradually multimerize and become recruited to the forming furrows. RNPs multimerization occurs prior to and during furrow initiation, as forming aggregates move outward through their association with the tips of growing interphase astral microtubules. Germ Plasm RNPs are also associated with short cortical F-actin. We show that, in embryos mutant for the cytoskeletal regulator mid1ip1l, Germ Plasm RNPs fail to become recruited to the furrow, accumulating instead at the periphery of the blastodisc. RNP aggregates are associated with zones of mid1ip1l-dependent cyclical local cortical F-actin network enrichments, as well as contractions at both the cortex and the contractile ring. F-actin inhibition in wild-type embryos mimics the RNP peripheral accumulation defect of mid1ip1l mutants. Our studies suggest that a common mechanism underlies distinct steps of Germ Plasm RNP segregation. At the cortex, this process attenuates microtubule-dependent outward RNP movement to retain RNPs in the blastodisc cortex and allow their recruitment to the furrows. F-actin network contraction likely also facilitates higher-order Germ Plasm RNP multimerization.
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Gradual recruitment and selective clearing generate Germ Plasm aggregates in the zebrafish embryo.
Bioarchitecture, 2013Co-Authors: Celeste Eno, Francisco PelegriAbstract:Determination of primordial Germ cells (PGCs) is one of the earliest decisions in animal embryogenesis. In many species, PGCs are determined through maternally-inherited Germ Plasm ribonucleoparticles (RNPs). In zebrafish, these are transmitted during oogenesis as dispersed RNPs, which after fertilization multimerize and become recruited as large aggregates at furrows for the first and second cell cycles. Here, we show that the number of recruited Germ Plasm RNPs is halved every cell cycle. We also show that Germ Plasm RNPs are recruited during the third cell cycle, but only transiently. Our data support a mechanism in which systematic local gathering of Germ Plasm RNPs during cytokinesis and threshold-dependent clearing contribute to forming Germ Plasm aggregates with the highest RNP number and Germ cell-inducing potential.
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Separate pathways of RNA recruitment lead to the compartmentalization of the zebrafish Germ Plasm.
Developmental biology, 2006Co-Authors: Elizabeth Theusch, Kimberly J. Brown, Francisco PelegriAbstract:The maternal RNAs vasa, dead end, nanos1, and daz-like all become localized to the peripheral ends of the first and second cleavage furrows, where they form part of the zebrafish Germ Plasm. We show that aggregates of a first class of Germ Plasm components, which include dead end, nanos1, and vasa RNAs, are initially present in a wide cortical band at the animal pole. Aggregates containing these three RNAs appear to be associated with f-actin, which during the first cell cycle undergoes a microtubule-dependent movement towards the periphery as well as circumferential alignment. These cytoskeletal rearrangements lead to the further aggregation of particles containing these RNAs and their concomitant recruitment to the forming furrow. Aggregates containing a second class of Germ Plasm RNA components, which include the transcript for daz-like, translocate along the plane of the cortex towards the animal pole, where they are recruited to the Germ Plasm. After recruitment to the furrow, these two classes of RNAs occupy overlapping yet distinct regions of the Germ Plasm, and this arrangement is maintained during the early cleavage stages. Our observations suggest that separate pathways of RNA recruitment facilitate the compartmentalization of the zebrafish Germ Plasm.
Mary Lou King - One of the best experts on this subject based on the ideXlab platform.
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Xenopus Xpat protein is a major component of Germ Plasm and may function in its organisation and positioning.
Developmental biology, 2005Co-Authors: Rachel J. Machado, Mary Lou King, Wendy Moore, Richard Hames, Evelyn Houliston, Patrick Chang, Hugh R. WoodlandAbstract:Abstract In many animals, including Drosophila, C. elegans, zebrafish and Xenopus, the Germ line is specified by maternal determinants localised in a distinct cytoPlasmic structure called the Germ Plasm. This is consists of dense granules, mitochondria, and specific localised RNAs. We have characterised the expression and properties of the protein encoded by Xpat, an RNA localised to the Germ Plasm of Xenopus. Immunofluorescence and immunoblotting showed that this novel protein is itself a major constituent of Germ Plasm throughout oogenesis and early development, although it is also present in other regions of oocytes and embryos, including their nuclei. We found that an Xpat-GFP fusion protein can localise correctly in cultured oocytes, in early oocytes to the ‘mitochondrial cloud’, from which Germ Plasm originates, and in later oocytes to the vegetal cortex. The localisation process was microtubule-dependent, while cortical anchoring required microfilaments. Xpat-GFP expressed in late stage oocytes assembled into circular fields of multi-particulate structures resembling endogenous fields of Germ Plasm islands. Furthermore these structures could be induced to form at ectopic sites by manipulation of culture conditions. Ectopic Xpat-GFP islands were able to recruit mitochondria, a major Germ Plasm component. These data suggest that Xpat protein has an important role in Xenopus Germ Plasm formation, positioning and maintenance.
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Germ Plasm and molecular determinants of Germ cell fate.
Current topics in developmental biology, 2000Co-Authors: Douglas W. Houston, Mary Lou KingAbstract:Abstract One mechanism for the specification of cell types during embryonic development is the cytoPlasmic localization of determinants in the egg into certain blastomeres. Primordial Germ cell (PGC) development in many organisms is characterized by the inheritance of Germ Plasm, a cytologically distinct assembly of mitochondria and electron-dense Germinal granules. This chapter reviews the structure of Germ Plasm and the experimental evidence for its importance in PGC specification inCaenorhabditis elegans, Drosophila, andXenopus. It then compares and contrasts recent data on the identification of Germ Plasm components in these organisms. Many components are potentially RNA-binding proteins, implicating the regulation of RNA metabolism, transport, and translation as critical processes in PGC development. Germ Plasm components also mediate transcriptional repression, regulate migration, and control mitotic divisions in PGCs. The chapter concludes with a discussion on the general roles of Germ Plasm components and how they might act to specify PGC fate.
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Xcat2 RNA is a translationally sequestered Germ Plasm component in Xenopus.
Mechanisms of Development, 1999Co-Authors: H Macarthur, Douglas W. Houston, M Bubunenko, Mary Lou KingAbstract:Abstract In Xenopus, the inheritance of Germ Plasm by a small subset of blastomeres during early development is thought to direct these cells into the Germ cell lineage. We show that Xcat2 RNA, related to Drosophila nanos, is a Germ Plasm component that is translationally repressed during oogenesis. Xcat2 protein was not detected in oocytes at times prior to, or after its RNA was localized in Germ Plasm, suggesting Xcat2 RNA is functionally sequestered soon after transcription. Indeed, Xcat2 RNA is found in a dense non-polysomal compartment in oocytes. Repression of translation was not relieved by substituting the Xcat2 3′UTR with that of β-globin. Immunodetection of Xcat2 protein during blastula and gastrula stages coincides with the time of symmetric segregation of the Germ Plasm and a net increase in the number of primordial Germ cells. Xcat2 is capable of binding RNA in vitro and we propose that it may function to translationally regulate other RNAs specific to primordial Germ cells.
Elizabeth R. Gavis - One of the best experts on this subject based on the ideXlab platform.
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Compartmentalized oskar degradation in the Germ Plasm safeguards Germline development
eLife, 2020Co-Authors: Catherine E Eichler, Anna C Hakes, Brooke Hull, Elizabeth R. GavisAbstract:Partitioning of mRNAs into ribonucleoprotein (RNP) granules supports diverse regulatory programs within the crowded cytoPlasm. At least two types of RNP granules populate the Germ Plasm, a cytoPlasmic domain at the posterior of the Drosophila oocyte and embryo. Germ granules deliver mRNAs required for Germline development to pole cells, the Germ cell progenitors. A second type of RNP granule, here named founder granules, contains oskar mRNA, which encodes the Germ Plasm organizer. Whereas oskar mRNA is essential for Germ Plasm assembly during oogenesis, we show that it is toxic to pole cells. Founder granules mediate compartmentalized degradation of oskar during embryogenesis to minimize its inheritance by pole cells. Degradation of oskar in founder granules is temporally and mechanistically distinct from degradation of oskar and other mRNAs during the maternal-to-zygotic transition. Our results show how compartmentalization in RNP granules differentially controls fates of mRNAs localized within the same cytoPlasmic domain.
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Corrigendum: Independent and coordinate trafficking of single Drosophila Germ Plasm mRNAs.
Nature cell biology, 2016Co-Authors: Shawn C. Little, Jack J. Lee, Kristina S. Sinsimer, Eric Wieschaus, Elizabeth R. GavisAbstract:Corrigendum: Independent and coordinate trafficking of single Drosophila Germ Plasm mRNAs
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Germ Plasm Anchoring Is a Dynamic State that Requires Persistent Trafficking
Cell reports, 2013Co-Authors: Kristina S. Sinsimer, Jack J. Lee, Stephan Y. Thiberge, Elizabeth R. GavisAbstract:Localized cytoPlasmic determinants packaged as ribonucleoprotein (RNP) particles direct embryonic patterning and cell fate specification in a wide range of organisms. Once established, the asymmetric distributions of such RNP particles must be maintained, often over considerable developmental time. A striking example is the Drosophila Germ Plasm, which contains RNP particles whose localization to the posterior of the egg during oogenesis results in their asymmetric inheritance and segregation of Germline from somatic fates in the embryo. Although actin-based anchoring mechanisms have been implicated, high-resolution live imaging revealed persistent trafficking of Germ Plasm RNP particles at the posterior cortex of the Drosophila oocyte. This motility relies on cortical microtubules, is mediated by kinesin and dynein motors, and requires coordination between the microtubule and actin cytoskeletons. Finally, we show that RNP particle motility is required for long-term Germ Plasm retention. We propose that anchoring is a dynamic state that renders asymmetries robust to developmental time and environmental perturbations.
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A late phase of Germ Plasm accumulation during Drosophila oogenesis requires Lost and Rumpelstiltskin
Development (Cambridge England), 2011Co-Authors: Kristina S. Sinsimer, Roshan A. Jain, Seema Chatterjee, Elizabeth R. GavisAbstract:Asymmetric mRNA localization is an effective mechanism for establishing cellular and developmental polarity. Posterior localization of oskar in the Drosophila oocyte targets the synthesis of Oskar to the posterior, where Oskar initiates the assembly of the Germ Plasm. In addition to harboring Germline determinants, the Germ Plasm is required for localization and translation of the abdominal determinant nanos. Consequently, failure of oskar localization during oogenesis results in embryos lacking Germ cells and abdominal segments. oskar accumulates at the oocyte posterior during mid-oogenesis through a well-studied process involving kinesin-mediated transport. Through live imaging of oskar mRNA, we have uncovered a second, mechanistically distinct phase of oskar localization that occurs during late oogenesis and results in amplification of the Germ Plasm. Analysis of two newly identified oskar localization factors, Rumpelstiltskin and Lost, that are required specifically for this late phase of oskar localization shows that Germ Plasm amplification ensures robust abdomen and Germ cell formation during embryogenesis. In addition, our results indicate the importance of mechanisms for adapting mRNAs to utilize multiple localization pathways as necessitated by the dramatic changes in ovarian physiology that occur during oogenesis.
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Transport of Germ Plasm on Astral Microtubules Directs Germ Cell Development in Drosophila
Current biology : CB, 2011Co-Authors: Dorothy A. Lerit, Elizabeth R. GavisAbstract:Summary Background In many organisms, Germ cells are segregated from the soma through the inheritance of the specialized Germ Plasm, which contains mRNAs and proteins that specify Germ cell fate and promote Germline development. Whereas Germ Plasm assembly has been well characterized, mechanisms mediating Germ Plasm inheritance are poorly understood. In the Drosophila embryo, Germ Plasm is anchored to the posterior cortex, and nuclei that migrate into this region give rise to the Germ cell progenitors, or pole cells. How the Germ Plasm interacts with these nuclei for pole cell induction and is selectively incorporated into the forming pole cells is not known. Results Live imaging of two conserved Germ Plasm components, nanos mRNA and Vasa protein, revealed that Germ Plasm segregation is a dynamic process involving active transport of Germ Plasm RNA-protein complexes coordinated with nuclear migration. We show that centrosomes accompanying posterior nuclei induce release of Germ Plasm from the cortex and recruit these components by dynein-dependent transport on centrosome-nucleated microtubules. As nuclei divide, continued transport on astral microtubules partitions Germ Plasm to daughter nuclei, leading to its segregation into pole cells. Disruption of these transport events prevents incorporation of Germ Plasm into pole cells and impairs Germ cell development. Conclusions Our results indicate that active transport of Germ Plasm is essential for its inheritance and ensures the production of a discrete population of Germ cell progenitors endowed with requisite factors for Germline development. Transport on astral microtubules may provide a general mechanism for the segregation of cell fate determinants.