Gap junctions in ovarian follicles of Drosophila melanogaster: inhibition and promotion of dye-coupling between oocyte and follicle cells

1993 ◽  
Vol 273 (1) ◽  
pp. 163-173 ◽  
Author(s):  
Johannes Bohrmann ◽  
Annette Haas-Assenbaum
Keyword(s):  
Drosophila Melanogaster ◽  
Gap Junctions ◽  
Ovarian Follicles ◽  
Follicle Cells ◽  
Dye Coupling

Antisera against a channel-forming 16 kDa protein inhibit dye-coupling and bind to cell membranes in Drosophila ovarian follicles

1993 ◽  
Vol 105 (2) ◽  
pp. 513-518 ◽  
Author(s):  
J. Bohrmann
Keyword(s):  
Gap Junctions ◽  
Lucifer Yellow ◽  
Affinity Purification ◽  
High Specificity ◽  
Ovarian Follicles ◽  
Immune Serum ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Dye Coupling ◽  
Mediated Communication

In Drosophila ovarian follicles, communication via gap junctions can be observed between the oocyte and its surrounding follicular epithelium. In the present study, the intercellular exchange of the fluorescent tracer Lucifer Yellow was analysed following pressure-injections of five different sera or protein solutions into the oocyte of stage-10 follicles. Three of the tested sera are directed against a channel-forming 16 kDa protein, which is a component of the vacuolar H(+)-ATPase and of Nephrops norvegicus gap junctions. When one of these antisera was injected 5–10 min prior to the dye, the percentage of follicles showing dye-coupling between oocyte and follicle cells was extremely small. On the other hand, injections of non-immune serum or of bovine serum albumin solution had only minor inhibitory effects. With indirect immunofluorescence, the three Nephrops antisera revealed a discrete punctate pattern at the membranes between neighbouring follicle cells as well as between follicle cells and oocyte. Most likely, this fluorescent pattern represents the distribution of gap junctions in the follicular epithelium. On immunoblots, the Nephrops antisera recognized a 29 kDa Drosophila ovary protein with high specificity. Affinity purification of one of these antisera against the 29 kDa protein revealed that this protein of Drosophila and the 16 kDa membrane-channel protein of Nephrops are immunologically related. Thus, the Nephrops antisera might help to reveal, in future injection experiments, the functional role of gap-junction mediated communication in Drosophila.

scholarly journals Effects of gap junction misexpression on synapses between auditory sensory neurons and the giant fiber of Drosophila melanogaster

2018 ◽  
Author(s):  
Sami H. Jezzini ◽  
Amelia Merced ◽  
Jonathan M. Blagburn
Keyword(s):  
Transcription Factor ◽  
Drosophila Melanogaster ◽  
Gap Junctions ◽  
Sensory Neurons ◽  
De Novo ◽  
Dye Coupling ◽  
Giant Fiber ◽  
Mixed Synapses ◽  
Chemical Synapses ◽  
Gap Junctional

AbstractThe synapse between auditory Johnston’s Organ neurons (JONs) and the giant fiber (GF) of Drosophila is structurally mixed, being composed of cholinergic chemical synapses and Neurobiotin-(NB) permeable gap junctions, which consist of the innexin Shaking-B (ShakB). Misexpression of one ShakB isoform, ShakB(N+16), in a subset of JONs that do not normally form gap junctions, results in their de novo dye coupling to the GF. This is similar to the effect of misexpression of the transcription factor Engrailed (En) in these same neurons, which also causes the formation of additional chemical synapses. In order to test the hypothesis that ShakB misexpression would similarly affect the distribution of chemical synapses, fluorescently-labeled presynaptic active zone protein (Brp) was expressed in JONs and the changes in its distribution were assayed with confocal microscopy. Both ShakB(N+16) and En increased the dye-coupling of JONs with the GF, indicating the formation of ectopic gap junctions. Conversely, expression of the ‘incorrect’ isoform, ShakB(N) abolishes dye coupling. However, while En misexpression increased the chemical contacts with the GF and the amount of GF medial branching, ShakB misexpression did not. ShakB immunocytochemistry showed that misexpression of ShakB(N+16) increases gap junctional plaques in JON axons but ShakB(N) does not. We conclude that both subsets of JON form chemical synapses onto the GF dendrites but only one population forms gap junctions, comprised of ShakB(N+16). Misexpression of this isoform in all JONs does not result in the formation of new mixed synapses but in the insertion of gap junctions, presumably at the sites of existing chemical synaptic contacts with the GF.

Types of intercellular junctions in teleost ovarian follicles (plecoglossus altivelis)

1978 ◽  
Vol 36 (2) ◽  
pp. 556-557
Author(s):  
K. Toshimori ◽  
C Ōura ◽  
F Yasuzumi
Keyword(s):  
Electron Microscope ◽  
Gap Junctions ◽  
Freeze Fracture ◽  
Intercellular Junctions ◽  
Ovarian Follicles ◽  
The Other ◽  
Follicle Cells ◽  
Plecoglossus Altivelis ◽  
Zonula Occludens ◽  
Intramembraneous Particles

In animal ovarian follicles, many investigators have reported various types of intercellular junctions such as desmosome (macula adherens), gap junction (nexus) and tight junction (zonula occludens). Between adjacent follicle cells, though both desmosomes and gap junctions were clearly presented, no tight junctions were ellucidated by electron microscope excepting Adams and Hertig (guinea pig;1964) and Espey and Stutts (rabbit;1972). On the other hand, between the oocyte and follicle cells, though desmosmes or desmosome-like areas were shown, no gap junctions were recognized to exist excepting Amsterdam et al. (1976) who suggested the presence of small gap junctions on rat oocyte surfaces and Anderson and Albertini (1976) who showed the presence of aggregations of intramembraneous particles on the oocyte surfaces in mouse, rat, rabbit and monkey. Types of intercellular junctions in animal ovarian follicles were not completely understood, because few workers applied freeze-fracture technique to demonstrate junctions excepting Anderson and Albertini (1976).

In vivo modulation of gap junctions and dye coupling between B-cells of the intact pancreatic islet

Diabetes ◽  
1983 ◽  
Vol 32 (9) ◽  
pp. 858-868 ◽  
Author(s):  
P. Meda ◽  
R. L. Michaels ◽  
P. A. Halban ◽  
L. Orci ◽  
J. D. Sheridan
Keyword(s):  
B Cells ◽  
Gap Junctions ◽  
Pancreatic Islet ◽  
Dye Coupling

Ultrastructural characteristics of the follicle cell-oocyte interface in the oogenesis of Ceratophrys cranwelli

Zygote ◽  
2002 ◽  
Vol 10 (2) ◽  
pp. 163-173 ◽  
Author(s):  
Evelina I. Villecco ◽  
Susana B. Genta ◽  
Alicia N. Sánchez Riera ◽  
Sara S. Sánchez
Keyword(s):  
Plasma Membrane ◽  
Granular Material ◽  
Gap Junctions ◽  
Close Contact ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Apical Surface ◽  
Coated Pits ◽  
Compact Zone ◽  
Vitelline Envelope

In this work we carried out an ultrastructural analysis of the cell interface between oocyte and follicle cells during the oogenesis of the amphibian Ceratophrys cranwelli, which revealed a complex cell-cell interaction. In the early previtellogenic follicles, the plasma membrane of the follicle cells lies in close contact with the plasma membrane of the oocyte, with no interface between them. In the mid-previtellogenic follicles the follicle cells became more active and their cytoplasm has vesicles containing granular material. Their apical surface projects cytoplasmic processes (macrovilli) that contact the oocyte, forming gap junctions. The oocyte surface begins to develop microvilli. At the interface both processes delimit lacunae containing granular material. The oocyte surface has endocytic vesicles that incorporate this material, forming cortical vesicles that are peripherally arranged. In the late previtellogenic follicle the interface contains fibrillar material from which the vitelline envelope will originate. During the vitellogenic period, there is an increase in the number and length of the micro- and macrovilli, which become regularly arranged inside fibrillar tunnels. At this time the oocyte surface exhibits deep crypts where the macrovilli enter, thus increasing the follicle cell-oocyte junctions. In addition, the oocyte displays coated pits and vesicles evidencing an intense endocytic activity. At the interface of the fully grown oocyte the fibrillar network of the vitelline envelope can be seen. The compact zone contains a fibrillar electron-dense material that fills the spaces previously occupied by the now-retracted microvilli. The macrovilli are still in contact with the surface of the oocyte, forming gap junctions.

scholarly journals Intercellular calcium signaling via gap junctions in glioma cells.

1992 ◽  
Vol 118 (1) ◽  
pp. 195-201 ◽  
Author(s):  
A C Charles ◽  
C C Naus ◽  
D Zhu ◽  
G M Kidder ◽  
E R Dirksen ◽  
...  
Keyword(s):  
Gap Junctions ◽  
Calcium Signaling ◽  
Single Cell ◽  
Mechanical Stimulation ◽  
Glioma Cells ◽  
C6 Glioma Cells ◽  
Dye Coupling ◽  
C6 Cells ◽  
Junction Protein ◽  
Stimulation Of

Calcium signaling in C6 glioma cells in culture was examined with digital fluorescence video microscopy. C6 cells express low levels of the gap junction protein connexin43 and have correspondingly weak gap junctional communication as evidenced by dye coupling (Naus, C. C. G., J. F. Bechberger, S. Caveney, and J. X. Wilson. 1991. Neurosci. Lett. 126:33-36). Transfection of C6 cells with the cDNA encoding connexin43 resulted in clones with increased expression of connexin43 mRNA and protein and increased dye coupling, as well as markedly reduced rates of proliferation (Zhu, D., S. Caveney, G. M. Kidder, and C. C. Naus. 1991. Proc. Natl. Acad. Sci. USA. 88:1883-1887; Naus, C. C. G., D. Zhu, S. Todd, and G. M. Kidder. 1992. Cell Mol. Neurobiol. 12:163-175). Mechanical stimulation of a single cell in a culture of non-transfected C6 cells induced a wave of increased intracellular calcium concentration ([Ca2+]i) that showed little or no communication to adjacent cells. By contrast, mechanical stimulation of a single cell in cultures of C6 clones expressing transfected connexin43 cDNA induced a Ca2+ wave that was communicated to multiple surrounding cells, and the extent of communication was proportional to the level of expression of the connexin43 cDNA. These results provide direct evidence that intercellular Ca2+ signaling occurs via gap junctions. Ca2+ signaling through gap junctions may provide a means for the coordinated regulation of cellular function, including cell growth and differentiation.

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