Faculty Mentor: Amanda Norvell. Student: Letitia Thompson. During Drosophila oogenesis, the TGF-alpha protein Gurken (Grk) is responsible for pattering the dorsal-ventral (D-V) axis of the egg and future embryo. Consequently, Grk distribution within the ovary is tightly controlled and the spatial and temporal regulation of Grk protein activity is, in part, achieved through post-transcriptional mechanisms. The goal of this project is to determine whether any aspects of Grk regulation are mediated through alterations in the polyadenylation of grk mRNA. Polyadenylation is the process of adding a poly(A) tail to the 3 untranslated region (UTR) of the mRNA. Hex sites (AAUAAA) are required in order for polyadenylation to occur. We have found that grk mRNA is polyadenylated throughout oogenesis, and moreover that there are two major polyadenylated grk transcripts that differ by approximately 15 nucleotides in size. The grk 3UTR does contain two Hex sites suggesting that alternative polyadenylation ...
The Notch receptor of Drosophila and its homologues in other organisms mediate cell-cell interactions required for the correct partitioning of cell fates within equivalence groups. Genes related to Notch and other components of the Notch signaling pathway represent a well conserved system for signal transduction, having been isolated from organisms as diverse as flies, worms, sea urchins, frogs, fish, chickens, mice, rats, and humans (reviewed by Lardelli et al., 1995). The expression and requirements for Notch signaling are pleiotropic through development, in contrast to other tissue or cell type specific receptors. How the Notch signaling cascade mediates pattern formation in so many tissues and cell types is not well understood. The research contained herein increases the understanding of Notch signaling by studying its role during Drosophila oogenesis. Additionally, this research lends insight into several important processes that take place during Drosophila oogenesis, including ...
During mid‐oogenesis, a massive supply of nucleotides is required for the synthesis of cellular DNA and RNA. Nurse cells in egg chambers of stages 2-10 undergo 10-12 cycles of endoreplication of nuclear DNA [21] producing an approximately 1,000‐fold increase in their DNA content. Endoreplication is essential to support increased transcription and protein production for deposition into developing oocytes [22]. Likewise, RNA production, particularly ribosomal RNA, is strikingly upregulated in nurse cells from these same stages in parallel with increases in ribosomal gene copy number [23]. The presence of CTPS filaments in Drosophila ovarian germ cells at stages with a high demand for CTP, together with the observation that reduced CTPS expression is associated with defects in oogenesis, suggests that CTPS filaments are assembled to promote CTP biosynthesis and support endoreplication. Consistent with this model, the diameters of DAck86 nurse cell nuclei were significantly smaller than ...
RNA localization is a cellular mechanism used to localize proteins to sub-cellular domains and to control protein synthesis regionally. In oocytes, RNA localization has profound implications for development, generating asymmetric protein distributions that promote morphological and functional cell polarization and establish regional fates in the future embryo. One such fate is that of the germ cell lineage. In Drosophila, germ cell formation depends on maternal inherited factors localized in the posterior pole region of oocytes and early embryos, named germ plasm. Oskar (Osk), a key determinant of germ plasm assembly, is both necessary and sufficient for germ-line formation and posterior patterning The localization of oskar (osk) mRNA starts during oogenesis and it is mediated by trans-acting factors several of which have been shown to have roles in post-transcriptional regulation of RNA, such as splicing, translational control and degradation. However, most of the molecular mechanisms ...
I used mutagenesis in the rescue scheme to determine whether a direct interaction between Spir and Capu is necessary during oogenesis. Previously, a point mutation was described in the Spir-KIND domain (Y232K) that abolishes interaction between Spir and Capu in binding assays and in pyrene actin polymerization assays (Vizcarra et al., 2011). In the same studies, SpirD with this mutation fails to colocalize with full-length Capu in tissue culture (S2) cells (Vizcarra et al., 2011). I, therefore, asked, what happens when I replace wild-type Spir with SpirB(Y232K)-GFP in flies? This construct failed to rescue the mutant phenotype in every aspect assayed. Flies expressing SpirB(Y232K)-GFP were sterile, had no detectable actin mesh during mid-oogenesis and consistently exhibited premature streaming (Fig. 3A,B, Table 1). Furthermore, streaming velocities were indistinguishable from the spir mutant (Fig. 3M). SpirB(Y232K)-GFP did not have a detectable effect on later stages of oogenesis in that, as ...
Recent work on Drosophila oogenesis has begun to reveal how the first asymmetries in development arise and how these relate to the later events that localise the positional cues which define the embryonic axes. The Cadherin-dependent positioning of the oocyte creates an anterior-posterior polarity t …
Functional characteristics of Myosin V and Broad Complex during Drosophila oogenesis identification and analysis of myosin genes in Drosophila ...
Dorsal-ventral (DV) patterning of the Drosophila embryo begins during oogenesis and relies on a series of intercellular signaling events in the egg chamber between the germline-derived oocyte and the somatically derived follicle cells (Ray and Schüpbach, 1996; Nilson and Schüpbach, 1999). The initial asymmetry for embryonic DV polarity is established at mid-oogenesis in the oocyte and is subsequently conveyed to the surrounding follicle cells. Spatial information generated within the follicular epithelium is then transmitted back to the germline, and is interpreted by the embryo after fertilization.. The initial polarizing signal from the oocyte to the follicle cells is determined by gurken (grk), which encodes a secreted transforming growth factor α (TGFα)-like protein (Neuman-Silberberg and Schüpbach, 1993). During mid-oogenesis, grk mRNA associated with the oocyte nucleus is localized to the dorsal anterior corner of the oocyte, resulting in restricted distribution of Grk protein and the ...
Phosphoinositides regulate myriad cellular processes, acting as potent signaling molecules in conserved signaling pathways and as organelle gatekeepers that recruit effector proteins to membranes. Phosphoinositide-generating enzymes have been studied extensively in yeast and cultured cells, yet their roles in animal development are not well understood. Here, we analyze Drosophila melanogaster phosphatidylinositol (PI) 4-kinase IIIα (PI4KIIIα) during oogenesis. We demonstrate that PI4KIIIα is required for production of plasma membrane PI4P and PI(4,5)P2 and is crucial for actin organization, membrane trafficking and cell polarity. Female germ cells mutant for PI4KIIIα exhibit defects in cortical integrity associated with failure to recruit the cytoskeletal-membrane crosslinker Moesin and the exocyst subunit Sec5. These effects reflect a unique requirement for PI4KIIIα, as egg chambers from flies mutant for either of the other Drosophila PI4Ks, fwd or PI4KII, show Golgi but not plasma ...
Dr. Veit Riechmann. Regulation of cytoskeletal dynamics in the Drosophila egg chamber. We aim to understand how the cytoskeleton mediates development. In particular, we are examining how the actomyosin cytoskeleton coordinates epithelial morphogenesis. In addition, we analyse the polarisation of the oocyte cytoskeleton and its role in axis determination.. We use Drosophila oogenesis as a model to investigate cytoskeletal dynamics. Oogenesis proceeds in small units called egg chambers. These simple organs consist of two tissues: an inner germline cyst of 1 oocyte and 15 nurse cells, and an outer epithelial layer (Fig. 1).. Two cell types are excellent models to study the cytoskeleton. First, the oocyte with its highly polarised microtubule cytoskeleton, along which the determinants of the embryonic axes are transported. Second, the outer epithelial cells, which provide an outstanding model to study epithelial polarisation.. The understanding of the mechanisms regulating the cytoskeleton is ...
In the majority of piRNA pathway mutations, the earliest phenotype is an increase in DNA damage in germline cells of the germarium (Klattenhoff et al., 2007, 2009). After stem cell division, the cystoblast proceeds through four incomplete divisions to produce a cyst of 16 interconnected cells that will differentiate into a single oocyte and the nurse cells (Spradling, 1993). Region 2a of the germarium contains early 16 cell cysts, and all 16 cells begin to accumulate double-strand breaks and initiate synaptonemal complex (SC) assembly (Carpenter, 1975, 1979). The SC is progressively restricted to a single oocyte, located at the posterior pole, as cysts progress to region 3, where they are surrounded by a monolayer of somatic follicle cells and bud from the germarium to form stage 2 egg chambers (Spradling et al., 1997). During the progression, meiotic DNA breaks are first restricted to the pro-oocyte and then repaired in the oocyte (Jang et al., 2003). Reorganization of the microtubule ...
... (vls) was identified as a posterior group gene in the initial screens for Drosophila maternal-effect lethal mutations (Schupbach, 1986). Despite its early genetic identification, it has not been characterized at the molecular level until now. vls encodes a divergent WD domain protein and the three available EMS-induced point mutations cause premature stop codons in the vls ORF. A null allele was identified that has a stronger phenotype than the EMS mutants. The vlsnull mutant shows that vls+ is required for high levels of Oskar protein to accumulate during oogenesis, for normal posterior localization of Oskar in later stages of oogenesis and for posterior localization of the Vasa protein during the entire process of pole plasm assembly. There is no evidence for vls being dependent on an upstream factor of the posterior pathway, suggesting that Valois protein (Vls) instead acts as a co-factor in the process. Based on the structure of Vls, the function of similar proteins in different ...
In the ovariole of Cynips, cell groups that have arisen in the initial period of oogenesis, presumably from one gonial cell, differentiate into the oocyte and 12 nurse cells (which constitute the nutritive chamber). The oocyte remains connected with the nurse cells by a strand of cytoplasm; the whole group acts as a physiological unit till the completion of vitellogenesis. Ribonucleoproteins are synthesized in the nurse cells and transmitted to the oocyte. The latter produces no detectable RNA.. There is no morphological evidence of any interchange of material between the nuclei or nucleoli and the cytoplasm of the oocyte or nurse cells.. Protein yolk components appear in the oocyte around the RNA inflow from the nurse cells. They associate with mucopolysaccharides, which appear in the same territory, to form carbohydrate-protein complexes. The synthesis of lipid yolk starts in the posterior part of the undifferentiated cell group and occurs subsequently only in the oocyte.. Nurse cells never ...
Polarity is a salient feature of oocytes. Consider, for example, the yolk-rich amphibian oocyte. As we shall discuss later, not only are organelles localized in the egg, but macromolecules may also have specific domains.. (See Browder et al., Fig. 3.11). As with sperm, mitochondria are significant oocyte organelles. They may be present in great abundance to fuel the events of early development, during which the embryo has no facility to produce new mitochondria of its own. (Remember that mitochondria are self-replicating.). An example is the amphibian Xenopus laevis. In somatic cells, the ratio of nuclear DNA:mitochondrial DNA is 100:1. In the fully-grown oocyte, that ratio has reversed to a range from 1:1 to 1:100. During mitochondrial replication in early oogenesis, mitochondria cluster around the nucleus to form a structure called the mitochondrial cloud.. (See Browder et al., Fig. 3.12) The cloud also contain electron-dense material called granulofibrillar material (GFM). The mitochondrial ...
ZHANG, YJ and Kunkel, JG, "PROGRAM OF F-ACTIN IN THE FOLLICULAR EPITHELIUM DURING OOGENESIS OF THE GERMAN-COCKROACH, BLATTELLA-GERMANICA" (1992). TISSUE & CELL. 283 ...
The normal differentiation of follicles from the preantral to the antral stage is regulated by the synthesis and secretion of several important growth factors. Moreover, the proper growth and development of the oocyte and its surrounding somatic granulosa-cumulus cells is accomplished through the activation of paracrine pathways that form a specific cross-talk between the gamete and somatic cells. It has been shown that several growth factors produced by the ovary are responsible for the proper growth and development of follicles. The developmental competence of mammalian oocytes (also termed developmental potency) is defined as the ability of female gametes to reach maturation (the MII stage) and achieve successful monospermic fertilisation. Proper oocyte development during folliculoand oogenesis also plays a critical role in normal zygote and blastocyst formation, as well as implantation and the birth of healthy offspring. Several molecular markers have been used to determine the developmental potency
The dramatic growth of ring canals during oogenesis requires both actin polymerization and depolymerization, making ring canals a valuable model for in vivo actin dynamics. The polarized movement of maternal mRNA and protein through ring canals from nurse cells to the oocyte is highly regulated. We identified proteins specifically targeted to the oocyte by GFP protein trapping; we are determining the mechanism of targeting using both live imaging and molecular dissection of the proteins to identify localization signals.. Specialized Terms: Molecular Genetics of Drosophila Oogenesis; Actin Cytoskeleton Regulation; Drosophila; Oogenesis; Ring Canal; Ovarian Muscle Function ...
New work from a collaboration between the Mitchison lab and our institute is out now in the journal Cell. Elvan Boke and colleagues propose that the Balbiani body, a non-membrane-bound compartment in vertebrate oocytes, is formed by amyloid-like assembly of proteins containing prion-like domains. The Balbiani body contains RNA, mitochondria, and other organelles needed by the early embryo after fertilization. The amyloid-like assembly of prion-like proteins in the Balbiani body (such as Xvelo in Xenopus) may form a protective compartment to help oocytes function as long-lived germ cells. The authors show that Xvelo forms a stable matrix with amyloid-like properties both in vivo and in vitro and that the association of Xvelo with the Balbiani body is dependent on Xvelos prion-like domain. See the graphical abstract below and read the full paper here: Boke et al, Cell 2016.. Congratulations to Elvan, our postdoc Martine Ruer, and the whole team!. ...
A schematic diagram showing folliculogenesis and oogenesis. The former involves the maturation of a follicle within the ovary while the latter involves the release of the ovum/egg from it, - Stock Image F002/0936
The villin like protein encoded by the Drosophila quail gene is required for actin bundle assembly during oogenesis is an eagle-i resource of type Journal article at eagle-i Network Shared Resource Repository.
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Hartshorne GM, Lyrakou S, Hamoda H, Oloto E, Ghafari F. Oogenesis and cell death in human prenatal ovaries: what are the criteria for oocyte selection? Mol Hum Reprod. 2009 Dec;15(12):805-19. doi: 10.1093/molehr/gap055. Epub 2009 Jul 7. PubMed PMID: 19584195; PubMed Central PMCID: PMC2776471. PMID:PMC2776471 (Link to Abstract) ...
Encore Healthcare Private Limited is part of a large privately owned pharmaceutical group, Encore Group. Leaders in contract manufacturing of finished formulations and active pharmaceutical ingredients for multinational companies around the world, Encore Group has recently vertically integrated into marketing and selling their own products under the name Encore Healthcare.
The Encore II contract includes all activities within the Military Services and DoD to satisfy their Information Technology (IT) requirements. IT solutions encompass a range of capabilities from old legacy systems to new, emerging net-centric technologies. Under these contracts, the contractor shall assist the government in providing IT solutions for activities throughout all operating levels of all customer organizations in support of all functional requirements including Command and Control (C2), Intelligence, and Mission support areas, and to all elements of the Global Information Grid (GIG).. The Encore II contract statement of work (Section C of the contract) contains a complete description of the task areas. All work provided for DoD organizations through the Encore contracts must be in accordance with approved DoD architectures, standards and guidelines. Customer statements of work, statements of objectives or performance work statements for individual task orders must reflect approved ...
Heres a complete explanation of what an oocyte is, plus an easy to understand explanation of oogenesis, from primordial germ cell to ovum.
Safety and efficacy are key issues in antiretroviral therapy (ART) selection. Efavirenz (EFV) is an important component of combination ART in treatment naive individuals. Like many drugs, there are inter-individual differences in the efficacy and tolerability of EFV. The Encore1 study provides an opportunity to examine the pharmacokinetics (PK)(processes by which a drug is absorbed, distributed, metabolized, and eliminated by the body) of EFV in blood samples collected over a 24-hour dosing interval in participants receiving either standard 600 mg or reduced 400 mg dose EFV once daily ...
Safety and efficacy are key issues in antiretroviral therapy (ART) selection. Efavirenz (EFV) is an important component of combination ART in treatment naive individuals. Like many drugs, there are inter-individual differences in the efficacy and tolerability of EFV. The Encore1 study provides an opportunity to examine the pharmacokinetics (PK)(processes by which a drug is absorbed, distributed, metabolized, and eliminated by the body) of EFV in blood samples collected over a 24-hour dosing interval in participants receiving either standard 600 mg or reduced 400 mg dose EFV once daily ...
Az Encore elképesztően jó módszer a szervezet népszerűsítésére. Bár nagy reklámfelülettel rendelkezik, mégis elég kicsi ahhoz, hogy a tenyérben elférjen. Az Encore egy hasznos LED-lámpával rendelkezik és könnyedén kapcsolható kulcscsomókhoz vagy Carabiner tartozékunkhoz. Kapható óriási 6,700 mAh kapacitású kivitelezésben.
During this episode guest and TAB Advisor, Randy Leavitt, shares his professional experience of over 30 years working for a government organization | Special Encore Presentation: Decision-Making: From Theory to Practice Monday, July 20, 2015 on Because Theres More | VoiceAmerica - The Leader in Internet Media
Dawn Doherty is a business development coach whose programs have | Special Encore Presentation: Dawn Doherty on How to Build and Grow a High Performing Team on Good Morning New York, Real Estate with Vince Rocco | VoiceAmerica - The Leader in Internet Media
Review standard and optional interior, exterior, mechanical comfort, entertainment equipment and their warranties for a 2017 Encore Preferred II Front-wheel Drive.
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Just got done ordering a Schlitter Encore, and picking up a lightly used CA2. Cant wait to ride the 700c CA2, but the Encore will be sized for DH who
1010-21-908-5833 - 1010219085833 NSN. Request Quotes, Buy Online. Get detailed information For National Stock Number (NSN) 1010-21-908-5833 - 1010219085833.
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The latest advancement in the treatment of aging skin, Bridge Therapy is a family of fractionated procedures delivered by the UltraPulse Encore CO2 laser.
INTRODUCTION : Larticulation temporo-mandibulaire (ATM) est un système articulaire excessivement complexe. Létiologie des désordres temporo-mandibulaires (DTM) est encore incertaine et le lien de cause à effet des ...
TY - JOUR. T1 - Ras signaling modulates activity of the Ecdysone Receptor EcR during cell migration in the drosophila ovary. AU - Hackney Price, Jennifer. AU - Pucci, Christina. AU - Naes, Erin. AU - Dobens, Leonard L.. PY - 2007/5. Y1 - 2007/5. N2 - Ecdysone Receptor (EcR) mediates effects of the hormone ecdysone during larval molts, pupal metamorphosis, and adult female oogenesis. In the ovary, egg chamber formation requires interactions between the somatic follicle cell (FC) epithelium and the germ line nurse cell/oocyte cyst. Previous work has shown EcR is required in the germ line for egg chamber maturation, and here we examine EcR requirements in the FC at late stages of oogenesis. EcR protein is ubiquitous in the FC but its activity is restricted, visualized by activity of the "ligand sensor" hs-GAL4-EcR ligand binding domain fusion and EcRE-lacZ reporter gene expression. GAL4-EcR is activated in the FC by an ecdysone agonist and repressed by tissue-specific Ras GTPase signals. To ...
The divisions of the germline stem cell are asymmetric in that they generate a renewing cell and a cell with the capacity to differentiate as an oocyte. Thereafter, the asymmetric meiotic divisions of oocytes produce one large cell, the egg, and two small polar bodies. In addition to asymmetric divisions, asymmetries are present in the form of localized cellular structures, organelles (mitochondria, endoplasmic reticulum, the oocyte nucleus), and also in the distribution of proteins and RNAs within the oocyte. All or a subset of these asymmetries are present in nearly all animals (Figure 3). For example, in most animals, the nucleus is in a central position within the early oocyte, but as oogenesis progresses, the oocyte nucleus moves to the oocyte periphery, or cortex (Figure 3). The side of the cell where the oocyte nucleus is localized in late-stage vertebrate oocytes is generally defined as the animal pole (Figure 3). Earlier asymmetries in oocytes are also shared among animals.
Ultrastructural studies of oogenesis in Bolinus brandaris are described. Although the initial phase of oogenesis is common to most animal species, vitellogenesis can be considered a species-specific characteristic. In the vitellogenesis of B.brandaris, mitochondria and endoplasmic reticula play a relevant role in the formation of myelinised membranous systems. Nuclear envelope, Golgi body and the oocyte plasma membrane invaginations are three possible origins for annulate lamellae. The latter can be considered membranous reservoirs. There are two sources for the vitellum: exogenous (from follicular cells) and endogenous (from the endoplasmic reticulum of the same oocyte ...
An encore is when performers in a live show give an additional performance after the planned show has ended, usually in response to extended applause from the audience. Multiple encores are not uncommon, and they originated spontaneously, when audiences would continue to applaud and demand additional performance from the artist(s). At the end of a concert, if there is prolonged applause, one more relatively short piece may be performed as an encore. In some modern circumstances, encores have come to be expected, and artists often plan their encores. Traditionally, in a concert that has a printed set list for the audience, encores are not listed, even when they are planned. A well-known example is the performance of the Radetzky March and The Blue Danube at the end of the Vienna New Years Concert by the Vienna Philharmonic Orchestra; neither piece is ever listed in the official program, but they are traditionally played every year. Beginning in the 18th century, if an aria was strongly ...
In most species, the cytoplasm of oocytes in primordial follicles exhibits organelles close to the nucleus or uniformly distributed throughout the cytoplasm (Figure 1A and 1B). In humans, groups of organelles are seen close to the nucleus and are named Balbiani bodies [54]. Balbiani body is a large distinctive collection of organelles asymmetrically located near the nucleus in very young oocytes, consisting of mitochondria and associated endoplasmic reticulum surrounding Golgi elements. Besides being well described in human oocytes, they are also found in oocytes of other species (vertebrates and invertebrates). Although the function of mammalian Balbiani body is unknown, this structure may have a possible role in nucleo-cytoplasmic transfer [55],[56].. In any case, the most abundant organelles found in primordial follicle oocytes are round-shaped mitochondria (Figure 1B) [44], which are known to be an immature form of this organelle and develop to an elongated shape as they become mature [57]. ...
Researchers from Mount Sinai in New York found a population of cells that are linked to the development of heart ventricular chambers.
A unique single cylinder engine was used to assess engine performance and combustion characteristics at three different strokes, with all other variables held constant. The engine utilized a production four-valve, pentroof cylinder head with an 86mm bore. The stock piston was used, and a variable de
... , Authors: Flavia R Mangone, Ana Carolina Pavanelli, Maria A. Nagai. Published in: Atlas Genet Cytogenet Oncol Haematol.
In fruit flies exposed to an electromagnetic field (all sources), significant more apoptotic follicles were found in comparison to the unexposed control. Additionally, the number of viable F1 pupae was significantly decreased after exposure to the diverse electromagnetic field sources when compared to the control group. However, no cumulative effect was found when exposure duration was increased or different exposure sources were used one after the other ...
Oogenesis vs Spermatogenesis Sex can be one of the most pleasurable things a couple can do. Some do it for fun while some do it for procreation. All of the
Oocyte development and maturity classification of boarfish (Capros aper) in the Northeast Atlantic. - ICES Journal of Marine Science, 69: 498-507. This study presents the first detailed investigation of the oocyte development and maturity classification of boarfish, Capros aper, which has recently become the target of an industrial fishery in the Northeast Atlantic. A total of 2014 boarfish were collected from January to December 2010. Mature male and female boarfish were sexually dimorphic and could be readily identified based on external characteristics. A comprehensive maturity scale was developed, which indicated that the length at 50% maturity for males and females was 9.7 cm total length. Female boarfish were observed to spawn in Irish waters in June and July. Once spawning ceased the remaining mature oocytes were resorbed. Preliminary analysis of reproductive strategy indicates that the boarfish is likely an asynchronous batch spawner with indeterminate fecundity ...
Definition of follicle cells in the Legal Dictionary - by Free online English dictionary and encyclopedia. What is follicle cells? Meaning of follicle cells as a legal term. What does follicle cells mean in law?
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