Charrasse S, Schroeder M, Gauthier-Rouviere C, Ango F, Cassimeris L, Gard D L, Larroque C
INSERM Unite 128, 34293 Montpellier, France.
J Cell Sci. 1998 May;111 ( Pt 10):1371-83. doi: 10.1242/jcs.111.10.1371.
We have recently identified a 6,449 bp cDNA, termed colonic, hepatic tumor over-expressed gene (ch-TOG), that is highly expressed in human tumors and brain. Its single open reading frame encodes a putative 218,000 Da polypeptide, TOGp. Antibodies generated against a bacterially expressed TOGp fragment specifically recognize a 218, 000 Da polypeptide in two human cell lines and in brain. Immunofluorescence microscopy using affinity-purified TOGp antibodies revealed that the distribution of TOGp was dependent upon the cell cycle. During interphase, TOGp was found concentrated in the perinuclear cytoplasm, where it co-localized with ER markers. In contrast anti-TOGp antibodies stained centrosomes and spindles in mitotic cells. TOGp co-sedimented with taxol-stabilized microtubules in vitro. Moreover, a TOGp enriched fraction promotes microtubule assembly both in solution and from nucleation centers. Finally, sequence comparison and immunologic cross-reaction suggest that TOGp is homologous to XMAP215, a previously described microtubule associated protein (MAP) from Xenopus eggs. These results suggest that TOGp is a MAP and that TOGp/XMAP215 may be necessary for microtubules rearrangements and spindle assembly in rapidly dividing cells.
我们最近鉴定出一个6449碱基对的cDNA，命名为结肠、肝肿瘤过度表达基因（ch-TOG），它在人类肿瘤和大脑中高度表达。其单一开放阅读框编码一个推定的218,000道尔顿多肽，即TOGp。针对细菌表达的TOGp片段产生的抗体在两个人类细胞系和大脑中特异性识别一种218,000道尔顿的多肽。使用亲和纯化的TOGp抗体进行的免疫荧光显微镜检查显示，TOGp的分布取决于细胞周期。在间期，TOGp集中在核周细胞质中，与内质网标记物共定位。相比之下，抗TOGp抗体在有丝分裂细胞中对中心体和纺锤体进行染色。TOGp在体外与紫杉醇稳定的微管共同沉降。此外，富含TOGp的组分在溶液中和从成核中心促进微管组装。最后，序列比较和免疫交叉反应表明，TOGp与XMAP215同源，XMAP215是先前描述的来自非洲爪蟾卵的微管相关蛋白（MAP）。这些结果表明，TOGp是一种MAP，并且TOGp/XMAP215可能是快速分裂细胞中微管重排和纺锤体组装所必需的。
