Functional expression of the murine connexin 36 gene coding for a neuron-specific gap junctional protein.
The mouse connexin 36 (Cx36) gene was mapped on chromosome 2 and an identical transcriptional start site was determined in brain and retina on exon I. Rabbit polyclonal antibodies to the presumptive cytoplasmic loop of the Cx36 protein recognized in immunohistochemical analyses Cx36 expression in the retina, olfactory bulb, hippocampus, inferior olive and cerebellum. In olivary neurons strong punctate labeling at dendritic cell contacts and weaker labeling in the cytoplasm of dendrites were shown by immuno electron microscopy. After expression of mouse Cx36 cDNA in human HeLa cells, neurobiotin transfer was increased 1.8-fold and electrical conductance at least 15-fold compared to untransfected HeLa cells. No Lucifer Yellow transfer was detected in either untransfected or Cx36 transfected HeLa cells. Single Cx36 channels in transfected HeLa cells showed a unitary conductance of 14.3 + or - 0. 8 pS. The sensitivity of Cx36 channels to transjunctional voltage was low in both HeLa-Cx36 cells and Xenopus oocytes expressing mouse Cx36. No increased transfer of neurobiotin was detected in heterotypic gap junctions formed by Cx36 and 9 other connexins expressed in HeLa cells. Our results suggest that Cx36 channels function as electrical synapses for transmission of electrical and metabolic signals between neurons in the central nervous system.
Institut für Genetik, Abteilung Molekulargenetik, Universität Bonn, Römerstr. 164, D-53117 Bonn, Germany.
B
B
Teubner
J
J
Degen
G
G
Söhl
M
M
Güldenagel
F F
FF
Bukauskas
E B
EB
Trexler
V K
VK
Verselis
C I
CI
De Zeeuw
C G
CG
Lee
C A
CA
Kozak
E
E
Petrasch-Parwez
R
R
Dermietzel
K
K
Willecke
D000818:Animals; D000918:Antibody Specificity; D016718:Arachidonic Acid / Q000494:pharmacology; D001483:Base Sequence; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism; D002245:Carbon Dioxide / Q000494:pharmacology; D002874:Chromosome Mapping; D017630:Connexins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology / Q000502:physiology; D003433:Crosses, Genetic; D004594:Electrophysiology; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D005456:Fluorescent Dyes / Q000378:metabolism; D017629:Gap Junctions / Q000737:chemistry*; D005796:Genes; D006367:HeLa Cells; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects; D007546:Isoquinolines / Q000378:metabolism; D008564:Membrane Potentials; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009115:Muridae; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology / Q000502:physiology; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D009865:Oocytes; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D012160:Retina / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D014982:Xenopus laevis; D000097004:Gap Junction delta-2 Protein
D016718:Arachidonic Acid; D001710:Biotin; D002245:Carbon Dioxide; D017630:Connexins; D005136:Eye Proteins; D005456:Fluorescent Dyes; D007546:Isoquinolines; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D000097004:Gap Junction delta-2 Protein; C070614:neurobiotin; C017475:lucifer yellow