title: The distribution and functional properties of Pelizaeus-Merzbacher-like disease-linked Cx47 mutations on Cx47/Cx47 homotypic and Cx47/Cx43 heterotypic gap junctions.
abstract: GJs (gap junctions) allow direct intercellular communication, and consist of Cxs (connexins). In the mammalian central nervous system, oligodendrocytes express Cx47, Cx32 and Cx29, whereas astrocytes express Cx43, Cx30 and Cx26. Homotypic Cx47/Cx47 GJs couple oligodendrocytes, and heterotypic Cx47/Cx43 channels are the primary GJs at oligodendrocyte/astrocyte junctions. Interestingly, autosomal recessive mutations in the gene GJC2 encoding Cx47 have been linked to a central hypomyelinating disease termed PMLD (Pelizaeus-Merzbacher-like disease). The aim of the present study was to determine the cellular distribution and functional properties of PMLD-associated Cx47 mutants (I46M, G149S, G236R, G236S, M286T and T398I). Expressing GFP (green fluorescent protein)-tagged mutant versions of Cx47 in gap-junction-deficient model cells revealed that these mutants were detected at the cell-cell interface similar to that observed for wild-type Cx47. Furthermore, four of the six mutants showed no electrical coupling in both Cx47/Cx47 and Cx47/Cx43 GJ channels. These results suggest that most of the PMLD-linked Cx47 mutants disrupt Cx47/Cx47 and Cx47/Cx43 GJ function in the glial network, which may play a role in leading to PMLD symptoms.
authors.affiliation: Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada, N6A 5C1.
authors.forename: Mi Seong
authors.initials: MS
authors.lastname: Kim
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Gloor
authors.forename: Donglin
authors.initials: D
authors.lastname: Bai
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D001483:Base Sequence; D000072259:Connexin 26; D018031:Connexin 43 / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D017630:Connexins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D017629:Gap Junctions / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D009457:Neuroglia / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D020371:Pelizaeus-Merzbacher Disease / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D018031:Connexin 43; D017630:Connexins; C500216:GJA1 protein, human; C000607042:GJB2 protein, human; D050505:Mutant Proteins; D011993:Recombinant Fusion Proteins; C427305:connexin 47; D000072259:Connexin 26