The inner ear contains heteromeric channels composed of Cx26 and Cx30 and deafness-related mutations in Cx26 have a dominant negative effect on Cx30
The inner ear contains heteromeric channels composed of Cx26 and Cx30 and deafness-related mutations in Cx26 have a dominant negative effect on Cx30
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DOI：
10.1080/cac.10.4-6.341.346
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发表时间：
2003-07-01
影响因子：
--
通讯作者：
Jagger, D
中科院分区：
文献类型：
--
作者：
Forge, A;Marziano, NK;Jagger, D
Cx26和cx30在哺乳动物耳蜗组织中共定位。用转染的HeLa细胞检测cx26和cx30之间的相互作用，以及cx26中与主要遗传性听力损失相关的四个点突变（W44S、G59A、D66H和R75W）对cx30的影响。当共表达时，wtcx26和wtcx30转运到相同的间隙连接斑块。细胞转移神经生物素，但不转移路西法黄，它可以自由地通过cx26通道，这表明cx30影响了cx26的特性。G59A和D66H单独表达时具有核周定位，而与cx30共表达时则转运到细胞膜上。与仅表达cx30的细胞相比，W44S、G59A或R75W与cx30共表达可显著减少神经生物素的转移。这些结果表明，cx26和cx30可以寡聚形成异聚连接子，并且某些cx26突变体对cx30有显性的负面影响。耳蜗薄片免疫金标记显示，cx26和cx30在单个间隙连接剖面两侧均匀分布。通过保留连接子的方法分离耳蜗膜蛋白，用cx30或cx26抗体分别沉淀出cx26和cx30。将路西法黄和神经生物素共同注射到耳蜗Corti器官的单个支持细胞中，神经生物素转移到许多细胞中，但路西法黄保留在注射细胞中。这些观察结果与耳蜗中由cx26/cx30异质连接子组成的连接一致。这些异质通道上的一些cx26突变引起的功能破坏可能是其对听力影响的非综合征性质的基础。
Cx26 and cx30 co-localize in tissues of the mammalian cochlea. Transfected HeLa cells were used to examine interactions between cx26 and cx30 and the effects on cx30 of four point mutations in cx26 that are associated with dominantly inherited hearing loss--W44S, G59A, D66H and R75W. When co-expressed, wtcx26 and wtcx30 trafficked to the same gap junction plaques. Cells transferred neurobiotin but not Lucifer Yellow, which passes freely through cx26 channels, suggesting cx30 affects the properties of cx26. G59A and D66H had a perinuclear localization when expressed alone but trafficked to the membrane when co-expressed with cx30. Co-expression of W44S, G59A or R75W with cx30, significantly reduced neurobiotin transfer in comparison with cells expressing cx30 only. These results indicate that cx26 and cx30 can oligomerize to form heteromeric connexons and demonstrate a dominant negative effect of some cx26 mutants on cx30. Immunogold labeling of thin sections of the cochlea showed both cx26 and cx30 distributed evenly on both sides of individual gap junction profiles. Immunoprecipitation of cochlear membrane proteins, isolated by procedures that preserve connexons, with either cx30 or cx26 antibodies precipitated both cx26 and cx30. Following co-injection of Lucifer Yellow and neurobiotin into individual supporting cells of the organ of Corti in cochlear slices, neurobiotin transferred to many cells, but Lucifer Yellow was retained in the injected cell. These observations are consistent with junctions composed of cx26/cx30 heteromeric connexons in the cochlea. The functional disruption caused by some cx26 mutations upon such heteromeric channels may underlie the non-syndromic nature of their effects on hearing.