Expression and modulation of connexin30.2, a novel gap junction protein in the mouse retina

2010 ◽  
Vol 27 (3-4) ◽  
pp. 91-101 ◽  
Author(s):  
LUIS PÉREZ DE SEVILLA MÜLLER ◽  
KARIN DEDEK ◽  
ULRIKE JANSSEN-BIENHOLD ◽  
ARNDT MEYER ◽  
MARIA M. KREUZBERG ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Gap Junction ◽  
Ganglion Cells ◽  
Electrical Coupling ◽  
Amacrine Cells ◽  
Mouse Retina ◽  
Coding Region ◽  
Transgenic Mouse Line ◽  
Junction Protein ◽  
Displaced Amacrine Cells

AbstractMammalian retinae express multiple connexins that mediate the metabolic and electrical coupling of various cell types. In retinal neurons, only connexin36, connexin45, connexin50, and connexin57 have been described so far. Here, we present an analysis of a novel retinal connexin, connexin30.2 (Cx30.2), and its regulation in the mouse retina. To analyze the expression of Cx30.2, we used a transgenic mouse line in which the coding region of Cx30.2 was replaced by lacZ reporter DNA. We detected the lacZ signal in the nuclei of neurons located in the inner nuclear layer and the ganglion cell layer (GCL). In this study, we focused on the GCL and characterized the morphology of the Cx30.2-expressing cells. Using immunocytochemistry and intracellular dye injections, we found six different types of Cx30.2-expressing ganglion cells: one type of ON-OFF, three types of OFF, and two types of ON ganglion cells; among the latter was the RGA1 type. We show that RGA1 cells were heterologously coupled to numerous displaced amacrine cells. Our results suggest that these gap junction channels may be heterotypic, involving Cx30.2 and a connexin yet unidentified in the mouse retina. Gap junction coupling can be modulated by protein kinases, a process that plays a major role in retinal adaptation. Therefore, we studied the protein kinase–induced modulation of coupling between RGA1 and displaced amacrine cells. Our data provide evidence that coupling of RGA1 cells to displaced amacrine cells is mediated by Cx30.2 and that the extent of this coupling is modulated by protein kinase C.

scholarly journals PTEN Expression Regulates Gap Junction Connectivity in the Retina

2021 ◽  
Vol 15 ◽  
Author(s):  
Ashley M. Chen ◽  
Shaghauyegh S. Azar ◽  
Alexander Harris ◽  
Nicholas C. Brecha ◽  
Luis Pérez de Sevilla Müller
Keyword(s):  
Gap Junction ◽  
Retinal Ganglion Cells ◽  
Vision Loss ◽  
Ganglion Cells ◽  
Dendritic Structure ◽  
Amacrine Cells ◽  
Mouse Retina ◽  
Retinal Ganglion ◽  
Cell Coupling ◽  
Cell Degeneration

Manipulation of the phosphatase and tensin homolog (PTEN) pathway has been suggested as a therapeutic approach to treat or prevent vision loss due to retinal disease. In this study, we investigated the effects of deleting one copy of Pten in a well-characterized class of retinal ganglion cells called α-ganglion cells in the mouse retina. In Pten+/– retinas, α-ganglion cells did not exhibit major changes in their dendritic structure, although most cells developed a few, unusual loop-forming dendrites. By contrast, α-ganglion cells exhibited a significant decrease in heterologous and homologous gap junction mediated cell coupling with other retinal ganglion and amacrine cells. Additionally, the majority of OFF α-ganglion cells (12/18 cells) formed novel coupling to displaced amacrine cells. The number of connexin36 puncta, the predominant connexin that mediates gap junction communication at electrical synapses, was decreased by at least 50% on OFF α-ganglion cells. Reduced and incorrect gap junction connectivity of α-ganglion cells will affect their functional properties and alter visual image processing in the retina. The anomalous connectivity of retinal ganglion cells would potentially limit future therapeutic approaches involving manipulation of the Pten pathway for treating ganglion cell degeneration in diseases like glaucoma, traumatic brain injury, Parkinson’s, and Alzheimer’s diseases.

Light Signaling in Scotopic Conditions in the Rabbit, Mouse and Rat Retina: A Physiological and Anatomical Study

2005 ◽  
Vol 93 (6) ◽  
pp. 3479-3488 ◽  
Author(s):  
Dario A. Protti ◽  
Nicolas Flores-Herr ◽  
Wei Li ◽  
Stephen C. Massey ◽  
Heinz Wässle
Keyword(s):  
Ganglion Cells ◽  
Electrical Coupling ◽  
Anatomical Study ◽  
Amacrine Cells ◽  
Light Signal ◽  
Mouse Retina ◽  
Dark Light ◽  
Scotopic Vision ◽  
Rat Retina ◽  
Alternative Pathways

In the dark, light signals are conventionally routed through the following circuit: rods synapse onto rod bipolar (RB) cells, which in turn contact AII amacrine cells. AII cells segregate the light signal into the on and off pathways by making electrical synapses with on cone bipolar (CB) cells and glycinergic inhibitory chemical synapses with off CB cells. These bipolar cells synapse onto their respective ganglion cells, which transfer on and off signals to the visual centers of the brain. Two alternative pathways have recently been postulated for the signal transfer in scotopic conditions: 1) electrical coupling between rods and cones, and 2) a circuit independent of cone photoreceptors, implying direct contacts between rods and off CB cells. Anatomical evidence supports the existence of both these circuits. To investigate the contribution of these alternative pathways to scotopic vision in the mammalian retina, we have performed patch-clamp recordings from ganglion cells in the dark-adapted retina of the rabbit, mouse, and rat. Approximately one-half of the ganglion cells in the rabbit retina received off signals through a circuit that was independent of RB cells. This was shown by their persistence in the presence of the glutamate agonist 2-amino-4-phosphonobutyric acid (APB), which blocks rod→RB cell signaling. Consistent with this result, strychnine, a glycine receptor antagonist, was unable to abolish these off responses. In addition, we were able to show that some off cone bipolar dendrites terminate at rod spherules and make potential contacts. In the mouse retina, however, there seems to be a very low proportion of off signals carried by an APB-resistant pathway. No ganglion cells in the rat retina displayed APB- and strychnine-resistant responses. Our data support signaling through flat contacts between rods and off CB cells as the alternative route, but suggest that the significance of this pathway differs between species.

scholarly journals All Spiking, Sustained ON Displaced Amacrine Cells Receive Gap-Junction Input from Melanopsin Ganglion Cells

2015 ◽  
Vol 25 (21) ◽  
pp. 2763-2773 ◽  
Author(s):  
Aaron N. Reifler ◽  
Andrew P. Chervenak ◽  
Michael E. Dolikian ◽  
Brian A. Benenati ◽  
Benjamin Y. Li ◽  
...  
Keyword(s):  
Gap Junction ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Displaced Amacrine Cells

scholarly journals Gap junctional coupling between retinal amacrine and ganglion cells underlies coherent activity integral to global object perception

2017 ◽  
Vol 114 (48) ◽  
pp. E10484-E10493 ◽  
Author(s):  
Kaushambi Roy ◽  
Sandeep Kumar ◽  
Stewart A. Bloomfield
Keyword(s):  
Gap Junctions ◽  
Long Range ◽  
Ganglion Cells ◽  
Electrical Coupling ◽  
Amacrine Cells ◽  
Spatial Separation ◽  
Object Perception ◽  
Mouse Retina ◽  
Genetic Ablation ◽  
Connexin 36

Coherent spike activity occurs between widely separated retinal ganglion cells (RGCs) in response to a large, contiguous object, but not to disjointed objects. Since the large spatial separation between the RGCs precludes common excitatory inputs from bipolar cells, the mechanism underlying this long-range coherence remains unclear. Here, we show that electrical coupling between RGCs and polyaxonal amacrine cells in mouse retina forms the synaptic mechanism responsible for long-range coherent activity in the retina. Pharmacological blockade of gap junctions or genetic ablation of connexin 36 (Cx36) subunits eliminates the long-range correlated spiking between RGCs. Moreover, we find that blockade of gap junctions or ablation of Cx36 significantly reduces the ability of mice to discriminate large, global objects from small, disjointed stimuli. Our results indicate that synchronous activity of RGCs, derived from electrical coupling with amacrine cells, encodes information critical to global object perception.

scholarly journals All Spiking, Sustained ON Displaced Amacrine Cells Receive Gap-Junction Input from Melanopsin Ganglion Cells

2015 ◽  
Vol 25 (21) ◽  
pp. 2878 ◽  
Author(s):  
Aaron N. Reifler ◽  
Andrew P. Chervenak ◽  
Michael E. Dolikian ◽  
Brian A. Benenati ◽  
Benjamin Y. Li ◽  
...  
Keyword(s):  
Gap Junction ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Displaced Amacrine Cells

The retinal ganglion cell distribution and the representation of the visual field in area 17 of the owl monkey, Aotus trivirgatus

1993 ◽  
Vol 10 (5) ◽  
pp. 887-897 ◽  
Author(s):  
L. C. L. Silveira ◽  
V. H. Perry ◽  
E. S. Yamada
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Ganglion Cell ◽  
Cell Density ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Temporal Region ◽  
Cell Distribution ◽  
Area 17 ◽  
Displaced Amacrine Cells

AbstractThe distribution of ganglion cells and displaced amacrine cells was determined in whole-mounted Aotus retinae. In contrast to diurnal simians, Aotus has only a rudimentary fovea. Ganglion cell density decreases towards the periphery at approximately the same rate along all meridians, but is 1.2–1.8 times higher in the nasal periphery when compared to temporal region at the same eccentricities. The total number of ganglion cells varied from 421,500 to 508,700. Ganglion cell density peaked at 15,000/mm2 at 0.25 mm dorsal to the fovea. The displaced amacrine cells have a shallow density gradient, their peak density in the central region is about 1500–2000/mm2 and their total number varied from 315,900 to 482,800. Comparison between ganglion cell density and areal cortical magnification factor for the primary visual cortex, area 17, shows that there is not a simple proportional representation of the ganglion cell distribution. There is an overrepresentation of the central 10 deg of the visual field in the visual cortex. The present results for Aotus and the results of a similar analysis of data from other primates indicate that the overrepresentation of the central visual field is a general feature of the visual system of primates.

scholarly journals Regulation of photoreceptor gap junction phosphorylation by adenosine in zebrafish retina

2014 ◽  
Vol 31 (3) ◽  
pp. 237-243 ◽  
Author(s):  
HONGYAN LI ◽  
ALICE Z. CHUANG ◽  
JOHN O’BRIEN
Keyword(s):  
Gap Junction ◽  
Dynamic Range ◽  
Electrical Coupling ◽  
Light Condition ◽  
Potent Effect ◽  
A2a Receptors ◽  
Junction Protein ◽  
A1 Receptor ◽  
Gap Junction Protein ◽  
Adenosine A2a

AbstractElectrical coupling of photoreceptors through gap junctions suppresses voltage noise, routes rod signals into cone pathways, expands the dynamic range of rod photoreceptors in high scotopic and mesopic illumination, and improves detection of contrast and small stimuli. In essentially all vertebrates, connexin 35/36 (gene homologs Cx36 in mammals, Cx35 in other vertebrates) is the major gap junction protein observed in photoreceptors, mediating rod–cone, cone–cone, and possibly rod–rod communication. Photoreceptor coupling is dynamically controlled by the day/night cycle and light/dark adaptation, and is directly correlated with phosphorylation of Cx35/36 at two sites, serine110 and serine 276/293 (homologous sites in teleost fish and mammals, respectively). Activity of protein kinase A (PKA) plays a key role during this process. Previous studies have shown that activation of dopamine D4 receptors on photoreceptors inhibits adenylyl cyclase, down-regulates cAMP and PKA activity, and leads to photoreceptor uncoupling, imposing the daytime/light condition. In this study, we explored the role of adenosine, a nighttime signal with a high extracellular concentration at night and a low concentration in the day, in regulating photoreceptor coupling by examining photoreceptor Cx35 phosphorylation in zebrafish retina. Adenosine enhanced photoreceptor Cx35 phosphorylation in daytime, but with a complex dose–response curve. Selective pharmacological manipulations revealed that adenosine A2a receptors provide a potent positive drive to phosphorylate photoreceptor Cx35 under the influence of endogenous adenosine at night. A2a receptors can be activated in the daytime as well by micromolar exogenous adenosine. However, the higher affinity adenosine A1 receptors are also present and have an antagonistic though less potent effect. Thus, the nighttime/darkness signal adenosine provides a net positive drive on Cx35 phosphorylation at night, working in opposition to dopamine to regulate photoreceptor coupling via a push–pull mechanism. However, the lower concentration of adenosine present in the daytime actually reinforces the dopamine signal through action on the A1 receptor.

scholarly journals Formation of retinal direction-selective circuitry initiated by starburst amacrine cell homotypic contact

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Thomas A Ray ◽  
Suva Roy ◽  
Christopher Kozlowski ◽  
Jingjing Wang ◽  
Jon Cafaro ◽  
...  
Keyword(s):  
Synapse Formation ◽  
Ganglion Cells ◽  
Plexiform Layer ◽  
Surface Protein ◽  
Amacrine Cells ◽  
Direction Selectivity ◽  
Mouse Retina ◽  
Inner Plexiform Layer ◽  
Starburst Amacrine Cells ◽  
Developing Neurons

A common strategy by which developing neurons locate their synaptic partners is through projections to circuit-specific neuropil sublayers. Once established, sublayers serve as a substrate for selective synapse formation, but how sublayers arise during neurodevelopment remains unknown. Here, we identify the earliest events that initiate formation of the direction-selective circuit in the inner plexiform layer of mouse retina. We demonstrate that radially migrating newborn starburst amacrine cells establish homotypic contacts on arrival at the inner retina. These contacts, mediated by the cell-surface protein MEGF10, trigger neuropil innervation resulting in generation of two sublayers comprising starburst-cell dendrites. This dendritic scaffold then recruits projections from circuit partners. Abolishing MEGF10-mediated contacts profoundly delays and ultimately disrupts sublayer formation, leading to broader direction tuning and weaker direction-selectivity in retinal ganglion cells. Our findings reveal a mechanism by which differentiating neurons transition from migratory to mature morphology, and highlight this mechanism’s importance in forming circuit-specific sublayers.

Molecular cloning of a rat uterine gap junction protein and analysis of gene expression during gestation

1991 ◽  
Vol 260 (5) ◽  
pp. E787-E793 ◽  
Author(s):  
L. M. Lang ◽  
E. C. Beyer ◽  
A. L. Schwartz ◽  
J. D. Gitlin
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Cdna Clone ◽  
Blot Analysis ◽  
Nucleotide Sequence Analysis ◽  
Uterine Tissue ◽  
Coding Region ◽  
Junction Protein ◽  
Gap Junction Protein ◽  
Rna Blot Analysis

To study the molecular mechanisms controlling the rapid increase in myometrial gap junctions observed in the parturient uterus, we have isolated a full-length cDNA clone corresponding to a rat uterine gap junction protein. Nucleotide sequence analysis of the cDNA clone reveals complete identity of the coding region with that of a previously reported heart gap junction protein (connexin43). Southern blot analysis suggests that the gene encoding this gap junction protein exists as a single copy in the rat haploid genome and contains no introns within the coding region. RNA blot analysis with this gap junction cDNA reveals a single 3.0-kb mRNA in uterine tissue without changes in transcript size throughout gestation. When normalized to the amount of 28S rRNA, the relative abundance of the connexin43 transcript in uterine tissue is quite constant between the nonpregnant state, during gestation, intrapartum, and postpartum. Similar size transcripts are shown by RNA blot analysis to be present in heart, lung, liver, brain, and skeletal muscle, and these transcripts are identified by the same 3'-nontranslated sequence probe. The results of these studies suggest that rat connexin43 is encoded by a single gene that is transcribed to identical transcripts in heart, uterus, and other tissues. They further suggest that changes in the abundance of connexin43 transcript are unlikely to be responsible for the abrupt increase in connexin43-containing myometrial gap junctions at term.

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