Time-related changes in connexin mRNA abundance in the rat neocortex during postnatal development

Prime, Graham; Horn, G.; Sutor, Bernd

doi:10.1016/s0165-3806(99)00132-7

Cited by 39 publications

(36 citation statements)

References 41 publications

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“…Nevertheless, our earlier western blotting results with the cross-reacting anti-Cx26 antibodies indicated that adult rat brain contains an abundance of Cx26 protein (Nagy et al, 1997b(Nagy et al, , 1999, which we confirm in the present study by northern and western analysis and by FRIL. Our northern blot results are consistent with findings that Cx26 mRNA is present at higher levels during the second and third postnatal weeks in developing brain than in adult brain (Prime et al, 2000).…”

Section: Discussionsupporting

confidence: 92%

Connexin26 in adult rodent central nervous system: Demonstration at astrocytic gap junctions and colocalization with connexin30 and connexin43

Nagy

Rempel

et al. 2001

J of Comparative Neurology

196

206

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The connexin family of proteins (Cx) that form intercellular gap junctions in vertebrates is well represented in the mammalian central nervous system. Among these, Cx30 and Cx43 are present in gap junctions of astrocytes. Cx32 is expressed by oligodendrocytes and is present in heterologous gap junctions between oligodendrocytes and astrocytes as well as at autologous gap junctions between successive myelin layers. Cx36 mRNA has been identified in neurons, and Cx36 protein has been localized at ultrastructurally defined interneuronal gap junctions. Cx26 is also expressed in the CNS, primarily in the leptomeningeal linings, but is also reported in astrocytes and in neurons of developing brain and spinal cord. To establish further the regional, cellular, and subcellular localization of Cx26 in neural tissue, we investigated this connexin in adult mouse brain and in rat brain and spinal cord using biochemical and immunocytochemical methods. Northern blotting, western blotting, and immunofluorescence studies indicated widespread and heterogeneous Cx26 expression in numerous subcortical areas of both species. By confocal microscopy, Cx26 was colocalized with both Cx30 and Cx43 in leptomeninges as well as along blood vessels in cortical and subcortical structures. It was also localized at the surface of oligodendrocyte cell bodies, where it was coassociated with Cx32. Freeze-fracture replica immunogold labeling (FRIL) demonstrated Cx26 in most gap junctions between cells of the pia mater by postnatal day 4. By postnatal day 18 and thereafter, Cx26 was present at gap junctions between astrocytes and in the astrocyte side of most gap junctions between astrocytes and oligodendrocytes. In perinatal spinal cord and in five regions of adult brain and spinal cord examined by FRIL, no evidence was obtained for the presence of Cx26 in neuronal gap junctions. In addition to its established localization in leptomeningeal gap junctions, these results identify Cx26 as a third connexin (together with Cx30 and Cx43) within astrocytic gap junctions and suggest a further level of complexity to the heterotypic connexin channel combinations formed at these junctions.

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Section: Discussionsupporting

confidence: 92%

Connexin26 in adult rodent central nervous system: Demonstration at astrocytic gap junctions and colocalization with connexin30 and connexin43

Nagy

Rempel

et al. 2001

J of Comparative Neurology

196

206

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“…By in situ hybridization, we detected Cx47 expression in nerve cells reported previously to be electrically coupled (De Zeeuw et al, 1995Chang et al, 1999;Prime et al, 2000;Traub and Bibbig, 2000) and in cerebellar Purkinje cells. It has to be shown that the Cx47 mRNA is translated into protein and leads to functional coupling in these cell types.…”

Section: Cx47 Expression Patternmentioning

confidence: 76%

“…Because the level of expression of several connexin mRNAs is modulated during brain development (cf. Prime et al, 2000), Cx47 expression was analyzed by Northern blotting in RNA preparations obtained from whole brains of prenatal and postnatal mice (Fig. 2b).…”

Section: Expression Pattern and Developmental Regulation Of Cx47mentioning

confidence: 99%

Functional Expression of the New Gap Junction Gene Connexin47 Transcribed in Mouse Brain and Spinal Cord Neurons

et al. 2001

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A new mouse gap junction gene that codes for a protein of 46,551 Da has been identified and designated connexin47 (Cx47). It mapped as a single-copy gene to mouse chromosome 11. In human HeLa cells and Xenopus oocytes, expression of mouse Cx47 or a fusion protein of Cx47 and enhanced green fluorescent protein induced intercellular channels that displayed strong sensitivity to transjunctional voltage. Tracer injections in Cx47-transfected HeLa cells revealed intercellular diffusion of neurobiotin, Lucifer yellow, and 4Ј,6-diamidino-2-phenylindole. Recordings of single channels yielded a unitary conductance of 55 pS main state and 8 pS substate. Cx47 mRNA expression was high in spinal cord and brain but was not found in retina, liver, heart, and lung. A low level of Cx47 expression was detected in ovaries. In situ hybridizations demonstrated high expression in ␣ motor neurons of the spinal cord, pyramidal cells of the cortex and hippocampus, granular and molecular layers of the dentate gyrus, and Purkinje cells of the cerebellum as well as several nuclei of the brainstem. This expression pattern is distinct from, although partially overlapping with, that of the neuronally expressed connexin36 gene. Thus, electrical synapses in adult mammalian brain are likely to consist of different connexin proteins depending on the neuronal subtype.

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“…Unlike transiently elevated levels of several connexins during brain development (Prime et al, 2000), Cx29 protein continuously increased to maximum levels in the adult CNS. The shift from robust immunolabeling for Cx29 in oligodendrocyte cell bodies at young ages to much lower levels in mature somata and increasing levels along myelinated fibers indicate a primary function of Cx29 in mature myelin.…”

Section: Cx29 Expression During Cns Developmentmentioning

confidence: 88%

Connexin29 and connexin32 at oligodendrocyte and astrocyte gap junctions and in myelin of the mouse central nervous system

Nagy

Ionescu

Lynn

et al. 2003

J of Comparative Neurology

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The cellular localization, relation to other glial connexins (Cx30, Cx32, and Cx43), and developmental expression of Cx29 were investigated in the mouse central nervous system (CNS) with an anti-Cx29 antibody. Cx29 was enriched in subcellular fractions of myelin, and immunofluorescence for Cx29 was localized to oligodendrocytes and myelinated fibers throughout the brain and spinal cord. Oligodendrocyte somata displayed minute Cx29-immunopositive puncta around their periphery and intracellularly. In developing brain, Cx29 levels increased during the first few postnatal weeks and were highest in the adult brain. Immunofluorescence labeling for Cx29 in oligodendrocyte somata was intense at young ages and was dramatically shifted in localization primarily to myelinated fibers in mature CNS. Labeling for Cx32 also was localized to oligodendrocyte somata and myelin and absent in Cx32 knockout mice. Cx29 and Cx32 were minimally colocalized on oligodendrocytes somata and partly colocalized along myelinated fibers. At gap junctions on oligodendrocyte somata, Cx43/Cx32 and Cx30/Cx32 were strongly associated, but there was minimal association of Cx29 and Cx43. Cx32 was very sparsely associated with astrocytic connexins along myelinated fibers. With Cx26, Cx30, and Cx43 expressed in astrocytes and Cx29, Cx32, and Cx47 expressed in oligodendrocytes, the number of connexins localized to gap junctions of glial cells is increased to six. The results suggested that Cx29 in mature CNS contributes minimally to gap junctional intercellular communication in oligodendrocyte cell bodies but rather is targeted to myelin, where it, with Cx32, may contribute to connexin-mediated communication between adjacent layers of uncompacted myelin. Indexing termsbrain; glia; antibodies; intercellular communication; confocal microscopy; Schmidt-Lanterman incisures Cells in the central nervous system (CNS) communicate directly via gap junctions at close appositions between plasma membranes, thereby providing channels for movement of ions and small molecules from cell to cell. It appears that virtually every neural cell type in the brain has the capacity for gap junctional intercellular communication (GJIC), and evidence for several levels of complexity in this process is beginning to emerge. Each cell type exhibits Mugnaini, 1986;Rash et al., 1997Rash et al., , 2000 Nagy et al., 2003a). In addition, vast numbers of gap junctions have been reported to connect not only astrocyte processes of different cells but also those of the same cell, resulting in extensive autocellular coupling formed by autologous or reflexive gap junctions (Wolburg and Rohlmann, 1995;Nagy and Rash, 2000). At least 10 members of the family of connexin proteins that form gap junctions in mammalian tissues are expressed in the CNS, and individual cells and gap junctions often contain two or more different connexins (Nagy et al., 1999;Severs, 1999;Nagy and Dermietzel, 2000;Nagy and Rash, 2000). It is now established that A/A junctions contain Cx26, Cx30, and Cx43, and th...

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Time-related changes in connexin mRNA abundance in the rat neocortex during postnatal development

Cited by 39 publications

References 41 publications

Connexin26 in adult rodent central nervous system: Demonstration at astrocytic gap junctions and colocalization with connexin30 and connexin43

Connexin26 in adult rodent central nervous system: Demonstration at astrocytic gap junctions and colocalization with connexin30 and connexin43

Functional Expression of the New Gap Junction Gene Connexin47 Transcribed in Mouse Brain and Spinal Cord Neurons

Connexin29 and connexin32 at oligodendrocyte and astrocyte gap junctions and in myelin of the mouse central nervous system

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