Connexin mutation that causes dominant congenital cataracts inhibits gap junctions, but not hemichannels, in a dominant negative manner.
Connexin mutation that causes dominant congenital cataracts inhibits gap junctions, but not hemichannels, in a dominant negative manner.
复制标题
DOI：
10.1242/jcs.034124
复制
发表时间：
2009-02-01
影响因子：
4
通讯作者：
Jiang JX
中科院分区：
文献类型：
--
作者：
Banks EA;Toloue MM;Shi Q;Zhou ZJ;Liu J;Nicholson BJ;Jiang JX
连接蛋白（Cx）50，E48K，突变与人类显性先天性白内障，然而，潜在的分子机制尚未得到表征。在位置48处的谷氨酸（E）残基在动物物种和连接蛋白类型中高度保守。当在成对的非洲爪蟾卵母细胞中表达时，人（h）和鸡（ch）Cx50 E48K突变体显示没有电耦合。此外，当与野生型Cx50异源配对或异源配对时，该突变以显性负性方式起作用，但对另一种透镜纤维连接蛋白Cx46没有这种影响。在相同系统中使用染料转移试验观察到类似的功能丧失和显性负效应。通过使用两种不同的染料转移方法，使用两种不同的示踪染料，我们发现通过逆转录病毒感染在鸡透镜胚胎成纤维细胞中表达的chCx 50 E48 K同样不能诱导染料偶联，并且阻止野生型chCx 50形成功能性间隙连接。与其对间隙连接的影响相反，E48K突变在卵母细胞中使用电导测定时对半通道活性没有影响，并且在细胞中机械诱导染料摄取。Cx 50在功能上参与细胞分化和透镜发育，并且E48 K突变体促进与野生型chCx 50无区别的原代透镜细胞分化，尽管其缺乏连接通道功能。这些数据共同表明，影响间隙连接但不影响Cx50半通道功能的突变可导致人类显性先天性白内障。这清楚地支持纤维细胞的细胞间耦合的模型，从而产生透镜透明度所需的营养物和代谢物的微循环。
The connexin (Cx) 50, E48K, mutation is associated with a human dominant congenital cataract; however, the underlying molecular mechanism has not been characterized. The glutamate (E) residue at position 48 is highly conserved across animal species and types of connexins. When expressed in paired Xenopus oocytes, human (h) and chicken (ch) Cx50 E48K mutants showed no electrical coupling. In addition, this mutation acts in a dominant negative manner when paired hetero-typically or hetero-merically with wild-type Cx50, but has no such effect on Cx46, the other lens fiber connexin. A similar loss-of-function and dominant negative effect was observed using dye transfer assays in the same system. By using two different dye transfer methods, with two different tracer dyes, we found chCx50 E48K expressed in chicken lens embryonic fibroblast cells by retroviral infection similarly failed to induce dye coupling, and prevented wild-type chCx50 from forming functional gap junctions. In contrast to its effect on gap junctions, the E48K mutation has no effect on hemichannel activity when assayed using electrical conductance in oocytes, and mechanically induced dye uptake in cells. Cx50 is functionally involved in cell differentiation and lens development, and the E48K mutant promotes primary lens cell differentiation indistinguishable from wild-type chCx50, despite its lack of junctional channel function. Together the data show that mutations affecting gap junctions but not hemichannel function of Cx50 can lead to dominant congenital cataracts in humans. This clearly supports the model of intercellular coupling of fiber cells creating a microcirculation of nutrients and metabolites required for lens transparency.
登录
查看更多内容
影响因子：
64.5
作者：
Gong, XH;Li, E;Gilula, NB
通讯作者：
Gilula, NB
影响因子：
4
作者：
Banks, Eric A.;Yu, X. Sean;Jiang, Jean X.
通讯作者：
Jiang, Jean X.
DOI：
10.1073/pnas.93.3.1287
发表时间：
1996-02-06
影响因子：
11.1
作者：
Jiang, JX;Goodenough, DA
通讯作者：
Goodenough, DA
DOI：
10.1152/ajpcell.2000.279.3.c596
发表时间：
2000-09-01
影响因子：
5.5
作者：
Pal, JD;Liu, XQ;Ebihara, L
通讯作者：
Ebihara, L
影响因子：
5.5
作者：
Bao, L;Sachs, F;Dahl, G
通讯作者：
Dahl, G