Guan Jikui, Ekwurtzel Emelie, Kvist Ulrik, Yuan Li
Department of Cell and Molecular Biology, Karolinska Institute, Berzelius väg 35, SE-171 77 Stockholm, Sweden.
Biochem Biophys Res Commun. 2008 Aug 8;372(4):761-4. doi: 10.1016/j.bbrc.2008.05.120. Epub 2008 Jun 2.
Structural maintenance of chromosome protein 1 (SMC1) is well known for its roles in sister chromatid cohesion and DNA repair. In this study, we report a novel centrosomal localization of SMC1 within the cytoplasm in a variety of mammalian cell lines. We showed that SMC1 localized to centrosomes throughout the cell cycle in a microtubule-independent manner. Biochemically, SMC1 was cofractionated with the centrosomal protein gamma-tubulin in centrosomal preparation. Immunohistochemistry and immunoelectron microscopy performed on mouse tissue sections revealed that SMC1 antibody strongly labeled the base of cilia in ciliated epithelia, where basal bodies were located. Furthermore, we showed that SMC1 was associated with both centrioles of a centrosome at G0/G1 stage of the cell cycle. These results demonstrate that SMC1 is a centrosomal protein, suggesting possible involvement of SMC1 in centrosome/basal body-related functions, such as organization of dynamic arrays of microtubules and ciliary formation.
染色体结构维持蛋白1(SMC1)因其在姐妹染色单体黏连和DNA修复中的作用而广为人知。在本研究中,我们报道了SMC1在多种哺乳动物细胞系的细胞质中一种新的中心体定位。我们发现,SMC1在整个细胞周期中以不依赖微管的方式定位于中心体。生化分析表明,在中心体制备过程中,SMC1与中心体蛋白γ-微管蛋白共分离。对小鼠组织切片进行的免疫组织化学和免疫电子显微镜分析显示,SMC1抗体强烈标记了纤毛上皮细胞中纤毛的基部,此处为基体所在位置。此外,我们还发现,在细胞周期的G0/G1期,SMC1与中心体的两个中心粒都有关联。这些结果表明,SMC1是一种中心体蛋白,提示SMC1可能参与了与中心体/基体相关的功能,如动态微管阵列的组织和纤毛形成。