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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2006-10-23
pubmed:abstractText
Mutations in GJB2, the gene encoding for the Gap Junction protein Connexin 26 (Cx26), have been established as the major cause of hereditary, non-syndromic hearing impairment (HI). We report here the identification of a novel point mutation in GJB2, c.40A>G [p.N14D], detected in compound heterozygosity with the c.35delG mutation in two brothers with moderate non-syndromic sensorineural HI. The mother who carried one wildtype and a p.N14D allele displayed normal hearing. The mutation leads to substitution of the neutral amino acid asparagine (N) by the negatively charged aspartic acid (D) at amino acid number 14, a position that is conserved among Cx26 of different organisms and among many other connexin isoforms. To investigate the impact of this mutation on protein function, Cx26 activity was measured by depolarization activated hemichannel conductance in non-coupled Xenopus laevis oocytes. Oocytes injected with the p.N14D mutant cRNA showed strongly reduced currents compared to wildtype. Coinjection of wildtype and mutant cRNA at equimolar levels restored the conductive properties supporting the recessive character of this mutation. Total Cx26 protein expression and cell surface abundance examined by western blotting and by quantitative immunoassays revealed that the hemichannel was properly synthesized but not integrated into the plasma membrane. In this study we have shown that the GJB2 mutation p.N14D is associated with recessively inherited HI and exhibits a defective phenotype due to diminished expression at the cell surface.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1098-1004
pubmed:author
pubmed:copyrightInfo
(c) 2006 Wiley-Liss, Inc.
pubmed:issnType
Electronic
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1158-9
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Deficient membrane integration of the novel p.N14D-GJB2 mutant associated with non-syndromic hearing impairment.
pubmed:affiliation
Department of Molecular Pathology, University Hospital of Tübingen, Germany. birgit.haack@med.uni-tuebingen.de
pubmed:publicationType
Journal Article, In Vitro, Case Reports, Research Support, Non-U.S. Gov't