GJC3

Gap junction gamma-3, also known as connexin-29 (Cx29) or gap junction epsilon-1 (GJE1), is a protein that in humans is encoded by the GJC3 gene.^[5]

GJC3
Identifiers
Aliases	GJC3, CX29, CX30.2, CX31.3, GJE1, gap junction protein gamma 3
External IDs	OMIM: 611925; MGI: 2153041; HomoloGene: 15399; GeneCards: GJC3; OMA:GJC3 - orthologs
Gene location (Human) Chr. Chromosome 7 (human)[1] Band 7q22.1 Start 99,923,266 bp[1] End 99,929,620 bp[1]
Gene location (Mouse) Chr. Chromosome 5 (mouse)[2] Band 5|5 G2 Start 137,951,723 bp[2] End 137,961,360 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in tibial nerve body of pancreas olfactory zone of nasal mucosa testicle minor salivary glands sural nerve lactiferous gland prostate skin of leg liver Top expressed in lumbar subsegment of spinal cord primary visual cortex superior frontal gyrus dentate gyrus of hippocampal formation granule cell cerebellar cortex gastrula deep cerebellar nuclei sciatic nerve globus pallidus anterior horn of spinal cord More reference expression data BioGPS n/a
Gene ontology Molecular function protein homodimerization activity gap junction channel activity involved in AV node cell-bundle of His cell electrical coupling Cellular component cell junction connexin complex plasma membrane myelin sheath membrane integral component of membrane gap junction Biological process myelination hearing cell communication AV node cell to bundle of His cell communication by electrical coupling Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 349149 118446 Ensembl ENSG00000176402 ENSMUSG00000056966 UniProt Q8NFK1 Q921C1 RefSeq (mRNA) NM_181538 NM_080450 RefSeq (protein) NP_853516 NP_536698 Location (UCSC) Chr 7: 99.92 – 99.93 Mb Chr 5: 137.95 – 137.96 Mb PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

GJC3 is a conexin.

Function

This gene encodes a gap junction protein. The encoded protein is known as a connexin, most of which form gap junctions that provide direct connections between neighboring cells.^[5] However, Cx29, which is highly expressed in myelin-forming glial cells of the CNS and PNS, has not been documented to form gap junctions in any cell type. In both PNS and CNS myelinated axons, Cx29 is precisely colocalized with Kv1.2 voltage-gated K+ channels, where both proteins are concentrated in the juxtaparanode and along the inner mesaxon.^[6] By freeze-fracture immunogold labeling electron microscopy, Cx29 is identified in abundant "rosettes" of transmembrane protein particles in the innermost layer of myelin, directly apposed to equally abundant immunogold-labeled Kv1.1 potassium channels, both in the juxtaparanodal axolemma and along the inner mesaxon.^[7] A role in K⁺ handling during saltatory conduction is implied but not yet demonstrated.

Clinical significance

Mutations in this gene have been reported to be associated with nonsyndromic hearing loss.^[5]

References

1. GRCh38: Ensembl release 89: ENSG00000176402 – Ensembl, May 2017
2. GRCm38: Ensembl release 89: ENSMUSG00000056966 – Ensembl, May 2017
3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
5. "Entrez Gene: gap junction protein".
6. Altevogt BM, Kleopa KA, Postma FR, Scherer SS, Paul DL (August 2002). "Connexin29 is uniquely distributed within myelinating glial cells of the central and peripheral nervous systems". The Journal of Neuroscience. 22 (15): 6458–70. doi:10.1523/JNEUROSCI.22-15-06458.2002. PMC 6758161. PMID 12151525.
7. Rash JE, Vanderpool KG, Yasumura T, Hickman J, Beatty JT, Nagy JI (April 2016). "KV1 channels identified in rodent myelinated axons, linked to Cx29 in innermost myelin: support for electrically active myelin in mammalian saltatory conduction". Journal of Neurophysiology. 115 (4): 1836–59. doi:10.1152/jn.01077.2015. PMC 4869480. PMID 26763782.

Further reading

• Hong HM, Yang JJ, Su CC, Chang JY, Li TC, Li SY (February 2010). "A novel mutation in the connexin 29 gene may contribute to nonsyndromic hearing loss". Human Genetics. 127 (2): 191–9. doi:10.1007/s00439-009-0758-y. PMID 19876648. S2CID 7892178.
• Ramchander PV, Panda KC, Panda AK (August 2010). "Mutations in the connexin 29 gene are not a major cause of nonsyndromic hearing impairment in India". Genetic Testing and Molecular Biomarkers. 14 (4): 539–41. doi:10.1089/gtmb.2010.0026. PMID 20632892.
• Kleopa KA, Orthmann JL, Enriquez A, Paul DL, Scherer SS (September 2004). "Unique distributions of the gap junction proteins connexin29, connexin32, and connexin47 in oligodendrocytes". Glia. 47 (4): 346–57. doi:10.1002/glia.20043. PMID 15293232. S2CID 9498256.
• Yang JJ, Wang WH, Lin YC, Weng HH, Yang JT, Hwang CF, Wu CM, Li SY (September 2010). "Prospective variants screening of connexin genes in children with hearing impairment: genotype/phenotype correlation". Human Genetics. 128 (3): 303–13. doi:10.1007/s00439-010-0856-x. PMID 20593197. S2CID 1423816.
• Söhl G, Nielsen PA, Eiberger J, Willecke K (2003). "Expression profiles of the novel human connexin genes hCx30.2, hCx40.1, and hCx62 differ from their putative mouse orthologues". Cell Communication & Adhesion. 10 (1): 27–36. doi:10.1080/15419060302063. PMID 12881038. S2CID 225894.
• Wang WH, Yang JJ, Lin YC, Yang JT, Chan CH, Li SY (2010). "Identification of novel variants in the Cx29 gene of nonsyndromic hearing loss patients using buccal cells and restriction fragment length polymorphism method". Audiology and Neuro-Otology. 15 (2): 81–7. doi:10.1159/000231633. PMID 19657183. S2CID 24962158.
• Altevogt BM, Kleopa KA, Postma FR, Scherer SS, Paul DL (August 2002). "Connexin29 is uniquely distributed within myelinating glial cells of the central and peripheral nervous systems". The Journal of Neuroscience. 22 (15): 6458–70. doi:10.1523/JNEUROSCI.22-15-06458.2002. PMC 6758161. PMID 12151525.
• Sargiannidou I, Ahn M, Enriquez AD, Peinado A, Reynolds R, Abrams C, Scherer SS, Kleopa KA (May 2008). "Human oligodendrocytes express Cx31.3: function and interactions with Cx32 mutants". Neurobiology of Disease. 30 (2): 221–33. doi:10.1016/j.nbd.2008.01.009. PMC 2704064. PMID 18353664.