Differential utilization of beta-tubulin isotypes in differentiating neurites.
Differential utilization of beta-tubulin isotypes in differentiating neurites.
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DOI：
10.1083/jcb.109.2.663
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发表时间：
1989-08
期刊：
影响因子：
--
通讯作者：
Cleveland DW
中科院分区：
文献类型：
--
作者：
Joshi HC;Cleveland DW
β-微管蛋白在脊椎动物基因组中由6 - 7个功能基因家族编码，这些功能基因产生6种不同的多肽同种型。我们现在的文件，虽然大鼠PC-12细胞表达五个这些同种型，只有两个（类II和III）积累显着的神经生长因子刺激的神经突生长的结果。与先前未能检测不同β-微管蛋白同种型之间的体内区别的努力相反，我们使用同种型特异性抗体的免疫印迹证明了三种β-微管蛋白多肽（I类、II类和IV类）优先用于神经突微管的组装（在聚合物中组装了约70%的I类和II类，但仅约50%的III类）。免疫荧光定位显示，一个额外的同种型（V）被部分排除在神经突之外。在体内定位的神经元特异性，III类同种型的区别也直接观察到使用免疫荧光和免疫金电子显微镜。这些努力的总和证明微管蛋白同种型之间确实存在一些体内功能差异。
beta-Tubulin is encoded in vertebrate genomes by a family of six to seven functional genes that produce six different polypeptide isotypes. We now document that although rat PC-12 cells express five of these isotypes, only two (classes II and III) accumulate significantly as a consequence of nerve growth factor-stimulated neurite outgrowth. In contrast to previous efforts that have failed to detect in vivo distinctions among different beta-tubulin isotypes, we demonstrate using immunoblotting with isotype-specific antibodies that three beta- tubulin polypeptides (classes I, II, and IV) are used preferentially for assembly of neurite microtubules (with approximately 70% of types I and II assembled but only approximately 50% of type III in polymer). Immunofluorescence localization shows that an additional isotype (V) is partially excluded from neurites. Distinctions in in vivo localization of the neuron-specific, class III isotype have also been directly observed using immunofluorescence and immunogold electron microscopy. The sum of these efforts documents that some in vivo functional differences between tubulin isotypes do exist.