The oligodendroglial precursor cell line Oli-neu represents a cell culture system to examine functional expression of the mouse gap junction gene connexin29 (Cx29)

Goran Söhl,Benjamin Odermatt,Sonja Hombach,Joachim Degen

doi:10.3389/fphar.2013.00083

Abstract

The potential gap junction forming mouse connexin29 (Cx29) protein is concomitantly expressed with connexin32 (Cx32) in peripheral myelin forming Schwann cells and together with both Cx32 and connexin47 (Cx47) in oligodendrocytes of the CNS. To study the genomic structure and functional expression of Cx29, either primary cells or cell culture systems might be selected, from which the latter are easier to cultivate. Both structure and expression of Cx29 is still not fully understood. In the mouse sciatic nerve, brain and the oligodendroglial precursor cell line Oli-neu the Cx29 gene is processed in two transcript isoforms both harboring a unique reading frame. In contrast to Cx32 and Cx47, only Cx29 protein is abundantly expressed in undifferentiated as well as differentiated Oli-neu cells but the absence of Etbr dye transfer after microinjection concealed the function of Cx29-mediated gap junction communication between those cells. Although HeLa cells stably transfected with Cx29 or Cx29-eGFP neither demonstrated any permeability for Lucifer yellow nor for neurobiotin, blocking of Etbr uptake from the media by gap junction blockers does suppose a role of Cx29 in hemi-channel function. Thus, we conclude that, due to its high abundance of Cx29 expression and its reproducible culture conditions, the oligodendroglial precursor cell line Oli-neu might constitute an appropriate cell culture system to study molecular mechanisms or putative extracellular stimuli to functionally open Cx29 channels or hemi-channels.

Highlights

Oligodendrocytes do myelinate neuronal axons in the central nervous system (CNS) to allow fast nerve conduction as well as guidance and care for neuronal networks
In the CNS, O-2A cells exist in two subpopulations with different maturation profiles: O-2Aperinatal cells are up-regulated in the rat postnatally, providing myelination during this period, but disappear about 6 weeks after birth (Wolswijk and Noble, 1989); O-2Aadult cells exist in the adult
GENOMIC STRUCTURE OF MOUSE CONNEXIN29 Untranslated sequence information (5 -untranslated region (UTR)) of two interrupted Cx29 cDNA clones have been aligned in the genomic Cx29 sequence from position −5049 to −4829, representing a putative untranslated Exon1 of 220 bp with a splice-donor site (CAG↓GTAAAT) at its 3 -end, that contains all criteria of canonical splice-donor sites (Padgett et al, 1986)

Summary

Introduction

Oligodendrocytes do myelinate neuronal axons in the CNS to allow fast nerve conduction as well as guidance and care for neuronal networks (cf. Kandel et al, 2000). Murine oligodendroglial cells express NGFs, which are important for oligodendrocyte-neuron interactions, essential for neuronal survival, redifferentiation, and remyelination (Byravan et al, 1994). In order to study such cell-cell interactions, O-2A progenitor cells were stably transfected with the t-neu tyrosine kinase (Jung et al, 1995). In the presence of demyelinated lesions, Oli-neu cells engage with demyelinated axons but do not differentiate further to swathe the axons (Jung et al, 1995)

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