Disease relevance of Gjb6

• This degeneration process is likely to account for the concomitant decrease of the endolymphatic potassium concentration and the aggravation of the hearing loss in adult Cx30((-/-)) mice [1].
• Further, Cx26 and Cx30 are induced in the epidermis adjacent to malignant melanoma but absent in the epidermis adjacent to benign non-epithelial skin lesions (melanocytic nevi and angioma) [2].

High impact information on Gjb6

• Cx26 and Cx30 are the two major Cx isoforms found in the cochlea, and they coassemble to form hybrid (heteromeric and heterotypic) gap junctions (GJs) [3].
• In the absence of the Cx30 gene, Cx26 expressed from extra alleles completely restored hearing sensitivity and prevented hair cell death in deaf Cx30(-/-) mice [3].
• We generated mice in which extra copies of the Cx26 gene were transgenically expressed from a modified bacterial artificial chromosome in a Cx30(-/-) background [3].
• The Cx30 ((-/-)) phenotype thus reveals the critical role of Cx30 both in generating the endocochlear potential and for survival of the auditory hair cells after the onset of hearing [1].
• The gap junction protein connexin30 (Cx30) is expressed in a variety of tissues that include epithelial and mesenchymal structures of the inner ear [1].

Biological context of Gjb6

• The coding region of mouse connexin-30 is uninterrupted by introns and is detected in the mouse genome as a single copy gene that is assigned to mouse chromosome 14 by analysis of mouse x hamster somatic cell hybrids [4].
• The distinct, continuous labeling of the luminal plasma membrane and upregulation by high salt suggest that Cx30 may function as a hemichannel involved in the regulation of salt reabsorption in the distal nephron [5].
• Our results revealed that gap junctions with different molecular configurations show differences in biochemical coupling, and that intercellular Ca(2+) signaling across heteromeric gap junctions consisting of Cx26 and Cx30 was at least twice as fast as their homomerically assembled counterparts [6].
• Recently, we have shown that deletion of Cx30, which is also expressed by astrocytes, affects exploration, emotionality, and neurochemistry in the mouse [7].
• To compare functional differences of gap junctions with different molecular configurations, homo- and heteromeric gap junctions composed of Cx26 and/or Cx30 were reconstituted by transfections in human embryonic kidney-293 cells [6].

Anatomical context of Gjb6

• Presence of Cx26 in astrocyte cultures was indicated by RT-PCR and by Western blot analysis, although we were unable to resolve whether it was contributed by contaminating cells; Cx30 mRNA was detected by Northern blot in long term (2 weeks) but not fresh cultures of astrocytes [8].
• Microinjection of connexin-30 cRNA into Xenopus oocytes induced formation of functional gap junction channels that gated somewhat asymmetrically in response to transjunctional voltage and at significantly lower voltage (Vo = +38 and -46 mV) than the closely homologous connexin-26 channels (Vo = 89 mV) [4].
• These results demonstrate that astrocyte Cx30 and oligodendrocyte Cx47 are widely present at A/O gap junctions [9].
• In this work we show that the two major forms of Cxs (Cx26 and Cx30) in the cochlea have overlapping expression patterns beginning at early embryonic stages [6].
• The Cx30-/- mice had elevated choline levels in the ventral striatum, possibly related to their aberrant behavioural phenotypes [10].

Associations of Gjb6 with chemical compounds

• Localization of connexin 30 in the luminal membrane of cells in the distal nephron [5].
• The Cx30+/- mice had lower dopamine and metabolite levels in the amygdala and ventral striatum and lower hippocampal 5-hydroxyindole acid (5-HIAA) concentrations relative to Cx30+/+ mice [10].
• Furthermore, the Cx30+/- mice had lower acetylcholine concentrations in the ventral striatum and higher choline levels in the neostriatum, relative to Cx30+/+ mice [10].

Other interactions of Gjb6

• Western blot analysis revealed that the content of both Cx43 and Cx30 remained relatively constant at 3, 7, and 21 months [11].

Analytical, diagnostic and therapeutic context of Gjb6

• We performed immunohistochemistry in the mouse, rat, and rabbit kidney to study the localization of Cx30 protein, a new member of the Cx family [5].
• Using reverse transcription/polymerase chain reaction and sequencing techniques, we show that Cx30 is abundant in pregnant and lactating mammary gland [12].

References