scholarly journals Distribution of yolk polypeptides in the follicle cells during the differentiation of the follicular epithelium in Sarcophaga bullata egg follicles

Development ◽  
1987 ◽  
Vol 101 (1) ◽  
pp. 33-43
Author(s):  
J. Geysen ◽  
J. Cardoen ◽  
A. De Loof
Keyword(s):  
Rna Synthesis ◽  
Follicle Cell ◽  
In Vitro Translation ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Current Pattern ◽  
Sarcophaga Bullata ◽  
Polypeptide Synthesis ◽  
Egg Follicles

In S. bullata, the ovaries contribute to the synthesis of yolk polypeptides. A specific antiserum for yolk polypeptides was used to visualize the presence of yolk polypeptides in the follicle cells during their differentiation. After vitellogenesis has started, all follicle cells contain yolk polypeptides. The squamous follicle cells covering the nurse cells and the border cells lose yolk polypeptides before mid-vitellogenesis, whereas the follicle cells over the oocyte contain yolk polypeptides until after late vitellogenesis. All follicle cells are immunonegative afterwards. In vitro translation of poly(A)+ RNA demonstrated that the presence of yolk polypeptide mRNA correlates well with follicle cell immunopositivity for yolk polypeptides. This suggests that the follicle cells synthesize the ovarian yolk polypeptides. Differences in cellular and nuclear morphology, total and poly(A)+ RNA synthesis and the rate of yolk polypeptide synthesis were shown to be correlated with the presence or absence of yolk polypeptides in the differentiating follicular epithelium. The possible relationship between these different aspects of follicle cell differentiation, follicle cell polyploidy and the extracellular current pattern around follicles are discussed.

Two actions of juvenile hormone on the follicle cells of Rhodnius prolixus Stål

1975 ◽  
Vol 53 (8) ◽  
pp. 1187-1188 ◽  
Author(s):  
Randa Abu-Hakima ◽  
K. G. Davey
Keyword(s):  
Juvenile Hormone ◽  
Developmental Stages ◽  
Normal Animal ◽  
Rhodnius Prolixus ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Intercellular Spaces

The follicular epithelium of vitellogenic oocytes from allatectomized females of Rhodnius fails to develop large intercellular spaces when exposed to juvenile hormone (JH) in vitro. This suggests that in the normal animal, the follicle cells require JH at two developmental stages. Differentiation of the cells in the presence of JH represents one requirement, and only those cells which have undergone this initial priming are fully competent to exhibit the second response, the development of intercellular spaces.

In vitro translation of encephalomyocarditis viral RNA: Synthesis of capsid precursor-like polypeptides

Virology ◽  
1976 ◽  
Vol 70 (2) ◽  
pp. 484-492 ◽  
Author(s):  
Lawrence A. Hunt
Keyword(s):  
Rna Synthesis ◽  
Viral Rna ◽  
In Vitro Translation ◽  
Capsid Precursor

Juvenile hormone increases ouabain-binding capacity of microsomal preparations from vitellogenic follicle cells

1983 ◽  
Vol 61 (7) ◽  
pp. 826-831 ◽  
Author(s):  
T. T. Ilenchuk ◽  
K. G. Davey
Keyword(s):  
Juvenile Hormone ◽  
Binding Capacity ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Curvilinear Relationship ◽  
Scatchard Analysis ◽  
Ouabain Binding ◽  
Binding Characteristics ◽  
Brain Microsomes

A comparison has been made of the effects of juvenile hormone (JH) on the binding characteristics for ouabain of microsomes prepared from brain and from cells of the follicular epithelium surrounding previtellogenic or vitellogenic oocytes in Rhodnius. JH has no effect on the binding of ouabain to brain microsomes and decreases the Kd, but does not alter the Bmax for previtellogenic follicle cells. For vitellogenic follicle cells, Scatchard analysis reveals a curvilinear relationship, which is interpreted as indicating that a new population of JH-sensitive ouabain-binding sites develops as the follicle cell enters vitellogenesis. These results are related to earlier data obtained on the effect of JH on ATPase activity, volume changes in isolated follicle cells, and the development of spaces between the cells of the follicular epithelium.

Patterning of the follicle cell epithelium along the anterior-posterior axis during Drosophila oogenesis

Development ◽  
1998 ◽  
Vol 125 (15) ◽  
pp. 2837-2846 ◽  
Author(s):  
A. Gonzalez-Reyes ◽  
D. St Johnston
Keyword(s):  
Follicle Cell ◽  
Cell Types ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Axis Formation ◽  
Main Body ◽  
Drosophila Oogenesis ◽  
Egfr Mutant ◽  
Anterior Posterior ◽  
Anterior Posterior Axis

Gurken signals from the oocyte to the adjacent follicle cells twice during Drosophila oogenesis; first to induce posterior fate, thereby polarising the anterior-posterior axis of the future embryo and then to induce dorsal fate and polarise the dorsal-ventral axis. Here we show that Gurken induces two different follicle cell fates because the follicle cells at the termini of the egg chamber differ in their competence to respond to Gurken from the main-body follicle cells in between. By removing the putative Gurken receptor, Egfr, in clones of cells, we show that Gurken signals directly to induce posterior fate in about 200 cells, defining a terminal competence domain that extends 10–11 cell diameters from the pole. Furthermore, small clones of Egfr mutant cells at the posterior interpret their position with respect to the pole and differentiate as the appropriate anterior cell type. Thus, the two terminal follicle cell populations contain a symmetric prepattern that is independent of Gurken signalling. These results suggest a three-step model for the anterior-posterior patterning of the follicular epithelium that subdivides this axis into at least five distinct cell types. Finally, we show that Notch plays a role in both the specification and patterning of the terminal follicle cells, providing a possible explanation for the defect in anterior-posterior axis formation caused by Notch and Delta mutants.

scholarly journals New poly(A)+RNAs appear coordinately during the differentiation of Naegleria gruberi amebae into flagellates.

1986 ◽  
Vol 102 (2) ◽  
pp. 353-361 ◽  
Author(s):  
J Mar ◽  
J H Lee ◽  
D Shea ◽  
C J Walsh
Keyword(s):  
Blot Analysis ◽  
Rna Synthesis ◽  
In Vitro Translation ◽  
Dot Blot ◽  
Cross Hybridization ◽  
Tubulin Mrna ◽  
Dot Blot Analysis ◽  
Rna Concentration ◽  
Naegleria Gruberi

We have examined the nature of the requirement for RNA synthesis during the differentiation of Naegleria gruberi amebae into flagellates (Fulton, C., and C. Walsh, 1980, J. Cell Biol., 85:346-360) by looking for poly(A)+RNAs that are specific to differentiating cells. A cDNA library prepared from poly(A)+RNA extracted from cells 40 min after initiation of the differentiation (40-min RNA), the time when formation of flagella becomes insensitive to inhibitors of RNA synthesis, was cloned into pBR322. Recombinant clones were screened for sequences that were complementary to 40-min RNA but not to RNA from amebae (0-min RNA). Ten of these differentiation-specific (DS) plasmids were identified. The DS plasmids were found to represent at least four different poly(A)+RNAs based on cross-hybridization, restriction mapping, and Northern blot analysis. Dot blot analysis was used to quantify changes in DS RNA concentration. The four DS RNAs appeared coordinately during the differentiation. They were first detectable at 10-15 min after initiation, reached a peak at 70 min as flagella formed, and then declined to low levels by 120 min when flagella reached full length. The concentration of the DS RNAs was found to be at least 20-fold higher in cells at 70 min than in amebae. The changes in DS RNA concentration closely parallel changes in tubulin mRNA as measured by in vitro translation (Lai, E.Y., C. Walsh, D. Wardell, and C. Fulton, 1979, Cell, 17:867-878).

scholarly journals Differential Rescue of Poliovirus RNA Replication Functions by Genetically Modified RNA Polymerase Precursors

2004 ◽  
Vol 78 (23) ◽  
pp. 13007-13018 ◽  
Author(s):  
Christopher T. Cornell ◽  
Jo Ellen Brunner ◽  
Bert L. Semler
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Genetically Modified ◽  
Rna Replication ◽  
Amino Acid Sequences ◽  
In Vitro Translation ◽  
Wild Type ◽  
Positive Strand ◽  
Positive Strand Rna

ABSTRACT We have previously described the RNA replication properties of poliovirus transcripts harboring chimeric RNA polymerase sequences representing suballelic exchanges between poliovirus type 1 (PV1) and coxsackievirus B3 (CVB3) utilizing an in vitro translation and RNA replication assay (C. Cornell, R. Perera, J. E. Brunner, and B. L. Semler, J. Virol. 78:4397-4407, 2004). We showed that three of the seven chimeras were capable of RNA replication in vitro, although replication levels were greatly reduced compared to that of wild-type transcripts. Interestingly, one of the replication-competent transcripts displayed a strand-specific RNA synthesis defect suggesting (i) a differential replication complex assembly mechanism involving 3D and/or precursor molecules (i.e., 3CD) required for negative- versus positive-strand RNA synthesis or (ii) effect(s) on the ability of the 3D polymerase to form higher-ordered structures required for positive-strand RNA synthesis. In this study, we have attempted to rescue defective RNA replication in vitro by cotranslating nonstructural proteins from a transcript encoding a large precursor polyprotein (P3) to complement 3D polymerase and/or precursor polypeptide functions altered in each of the chimeric constructs. Utilization of a wild-type P3 construct revealed that all transcripts containing chimeric PV1/CVB3 polymerase sequences can be complemented in trans for both negative- and positive-strand RNA synthesis. Furthermore, data from experiments utilizing genetically modified forms of the P3 polyprotein, containing mutations within 3C or 3D sequences, strongly suggest the existence of different protein-protein and protein-RNA interactions required for positive- versus negative-strand RNA synthesis. These results, combined with data from in vitro RNA elongation assays, indicate that the delivery of active 3D RNA polymerase to replication complexes requires a series of macromolecular interactions that rely on the presence of specific 3D amino acid sequences.

scholarly journals Establishment of dorsal-ventral polarity of theDrosophilaegg requirescapicuaaction in ovarian follicle cells

Development ◽  
2001 ◽  
Vol 128 (22) ◽  
pp. 4553-4562 ◽  
Author(s):  
Deborah J. Goff ◽  
Laura A. Nilson ◽  
Donald Morisato
Keyword(s):  
Target Genes ◽  
Nuclear Translocation ◽  
Ovarian Follicle ◽  
Growth Factor Receptor ◽  
Follicle Cell ◽  
Dorsal Side ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Egfr Signaling ◽  
Cell Nuclei

The dorsal-ventral pattern of the Drosophila egg is established during oogenesis. Epidermal growth factor receptor (Egfr) signaling within the follicular epithelium is spatially regulated by the dorsally restricted distribution of its presumptive ligand, Gurken. As a consequence, pipe is transcribed in a broad ventral domain to initiate the Toll signaling pathway in the embryo, resulting in a gradient of Dorsal nuclear translocation. We show that expression of pipe RNA requires the action of fettucine (fet) in ovarian follicle cells. Loss of maternal fet activity produces a dorsalized eggshell and embryo. Although similar mutant phenotypes are observed with regulators of Egfr signaling, genetic analysis suggests that fet acts downstream of this event. The fet mutant phenotype is rescued by a transgene of capicua (cic), which encodes an HMG-box transcription factor. We show that Cic protein is initially expressed uniformly in ovarian follicle cell nuclei, and is subsequently downregulated on the dorsal side. Earlier studies described a requirement for cic in repressing zygotic target genes of both the torso and Toll pathways in the embryo. Our experiments reveal that cic controls dorsal-ventral patterning by regulating pipe expression in ovarian follicle cells, before its previously described role in interpreting the Dorsal gradient.

Protein Synthesis and Uptake by Isolated Cecropia Oocytes

1971 ◽  
Vol 8 (3) ◽  
pp. 735-750
Author(s):  
LUCY M. ANDERSON
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Perchloric Acid ◽  
Selection Process ◽  
Ovarian Follicle ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Blood Proteins ◽  
Cell Product

A procedure has been developed for separating the oocytes and follicular epithelium-nurse cell complexes making up the vitellogenic ovarian follicle of the Cecropia moth. Both components remained viable during short-term in vitro incubation in female blood. Isolated epithelial cells were found by autoradiography to incorporate tritiated amino acids and to secrete a fixable, non-dialysable labelled material. Isolated oocytes incubated in a blood medium containing this tritiated, dialysed follicle cell product incorporated it in small cortical yolk bodies, presumably by pinocytosis. Quantitative perchloric acid-precipitation and scintillation counting indicated that the amount of labelled material incorporated by the oocytes increased with time. These results provide direct confirmation of a follicle contribution to the yolk. Isolated oocytes were also tested for their ability to incorporate labelled amino acids. Fixable label was observed autoradiographically throughout the oocyte cytoplasm, with the greatest concentration in the cortex, but little appeared in the yolk spheres. The amount of perchloric acid-precipitable amino acid in oocytes incubated in female blood increased with time for up to 2 h and then remained constant or decreased slightly. In medium that had been previously conditioned by follicle cells and dialysed, however, incorporation of labelled amino acid continued for at least 4 h. A possible interpretation of this result is that stimulation of pinocytosis by the epithelial cell products causes increased turnover of cell membrane and demands continued synthesis of new proteins. Labelled female blood proteins were not incorporated into yolk to an appreciable extent by isolated oocytes, even in the presence of follicle cell product. Perhaps extracellular preconcentration, as occurs in the intact follicle, is necessary for effective accrual of blood proteins. The female blood proteins did become associated with the oocyte cortex, however, and exhibited a higher affinity for the oocyte than male blood proteins. Thus preferential adsorption to the oocyte surface may be a component of the selection process in vitellogenesis.

Ectopic activation of torpedo/Egfr, a Drosophila receptor tyrosine kinase, dorsalizes both the eggshell and the embryo

Development ◽  
1997 ◽  
Vol 124 (19) ◽  
pp. 3871-3880 ◽  
Author(s):  
A.M. Queenan ◽  
A. Ghabrial ◽  
T. Schupbach
Keyword(s):  
Cell Fate ◽  
Growth Factor Receptor ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Cell Fates ◽  
Egfr Activation ◽  
Egg Chamber ◽  
Anterior Posterior ◽  
Anterior Posterior Axis

The Drosophila gene torpedo/Egfr (top/Egfr) encodes a homolog of the vertebrate Epidermal Growth Factor receptor. This receptor is required several times during the life cycle of the fly for the transmisson of developmental cues. During oogenesis, Top/Egfr activation is required for the establishment of the dorsal/ventral axis of the egg and the embryo. To examine how ectopic Top/Egfr activation affects cell fate determination, we constructed an activated version of the protein. Expression of this activated form (lambda top) in the follicle cells of the ovary induces dorsal cell fates in both the follicular epithelium and the embryo. Different levels of expression resulted in different dorsal follicle cell fates. These dorsal cell fates were expanded in the anterior, but not the posterior, of the egg, even in cases where all the follicle cells covering the oocyte expressed lambda top. The expression of genes known to respond to top/Egfr activation, argos (aos), kekkon1 (kek 1) and rhomboid (rho), was also expanded in the presence of the lambda top construct. When lambda top was expressed in all the follicle cells covering the oocyte, kek 1 and argos expression was induced in follicle cells all along the anterior/posterior axis of the egg chamber. In contrast, rho RNA expression was only activated in the anterior of the egg chamber. These data indicate that the response to Top/Egfr signaling is regulated by an anterior/posterior prepattern in the follicle cells. Expression of lambda top in the entire follicular epithelium resulted in an embryo dorsalized along the entire anterior/posterior axis. Expression of lambda top in anterior or posterior subpopulations of follicle cells resulted in regionally autonomous dorsalization of the embryos. This result indicates that subpopulations of follicle cells along the anterior/posterior axis can respond to Top/Egfr activation independently of one another.

Synthesis of a ribosome-bound translatable poly(A)− mRNA during spore germination in Dictyostelium discoideum

1989 ◽  
Vol 35 (5) ◽  
pp. 573-577
Author(s):  
S. Ramagopal
Keyword(s):  
Dictyostelium Discoideum ◽  
Spore Germination ◽  
Gel Electrophoresis ◽  
Rna Synthesis ◽  
In Vitro Translation ◽  
Cellular Slime Mold ◽  
Free System ◽  
Cellular Slime

A distinct poly(A)− RNA sedimenting around 10–12S was identified during spore germination in Dictyostelium discoideum. Activated spores were labeled with [3H]uracil and the poly(A)− RNA was purified from ribosomal particles for analysis. In the spore swelling stage, 40 to 50% of the newly synthesized poly(A)− RNA was 10–12S RNA. This fraction diminished to one-half or one-fourth depending on the labeling period at the stage of amoeba emergence. The 10–12S RNA was associated with both monosomes and polysomes in vivo. Translation in a wheat germ cell-free system and gel electrophoresis demonstrated that the 10–12S RNA coded for a number of polypeptides, some of which were also represented among the in vitro products of poly(A)+ RNA. However, there were seven unique polypeptides (37.5, 28.2, 27.5, 23, 17.7, 17, and 14.2 kilodaltons) encoded exclusively by 10–12S RNA.Key words: cellular slime mold, RNA synthesis, development, poly(A)− mRNA, in vitro translation.

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