Sale W S, Besharse J C, Piperno G
Department of Anatomy and Cell Biology, Emory University School of Medicine, Atlanta, GA 30322.
Cell Motil Cytoskeleton. 1988;9(3):243-53. doi: 10.1002/cm.970090306.
We have used the mouse monoclonal antibody 6-11 B-1, specific for acetylated alpha-tubulin, to determine the distribution of acetylated alpha-tubulin in in vitro-assembled microtubules and retinal tissue. Analysis by immunoblots revealed that microtubules assembled from bovine brain extracts contain both acetylated and nonacetylated alpha-tubulin. Immunofluorescence, using 6-11 B-1 and antitubulin B-5-1-2, a monoclonal antibody specific for alpha-tubulin, demonstrated the colocalization of both alpha-tubulin species in neurons of the retina and that acetylated microtubules are relatively abundant in neurons. However, analysis at higher resolution revealed that rod photoreceptors contain spatially distinct microtubule arrays which differ in content of acetylated alpha-tubulin and differ in stability. Acetylated microtubules which composed those of the rod outer segment and connecting cilium were resistant to depolymerization in nocodazole or colchicine. In contrast, the nonacetylated microtubules which composed those of the rod-inner segment were depolymerized in nocodazole or colchicine. Therefore, these acetylated microtubules are more resistant to depolymerization than non-acetylated microtubules.
我们使用了对乙酰化α-微管蛋白具有特异性的小鼠单克隆抗体6-11 B-1，来确定乙酰化α-微管蛋白在体外组装的微管和视网膜组织中的分布。免疫印迹分析显示，从牛脑提取物组装的微管同时含有乙酰化和非乙酰化的α-微管蛋白。使用6-11 B-1和抗微管蛋白B-5-1-2（一种对α-微管蛋白具有特异性的单克隆抗体）进行免疫荧光分析，证明了两种α-微管蛋白在视网膜神经元中共定位，并且乙酰化微管在神经元中相对丰富。然而，更高分辨率的分析显示，视杆光感受器含有空间上不同的微管阵列，其乙酰化α-微管蛋白的含量不同，稳定性也不同。构成视杆外段和连接纤毛的乙酰化微管对诺考达唑或秋水仙碱诱导的解聚具有抗性。相反，构成视杆内段的非乙酰化微管在诺考达唑或秋水仙碱作用下会解聚。因此，这些乙酰化微管比非乙酰化微管更抗解聚。
