Lin D C, Levin P A, Grossman A D
Department of Biology, Building 68-530, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Proc Natl Acad Sci U S A. 1997 Apr 29;94(9):4721-6. doi: 10.1073/pnas.94.9.4721.
We have determined the subcellular localization of the chromosome partition protein Spo0J of Bacillus subtilis by immunofluorescence microscopy and visualizing fluorescence of a Spo0J-GFP fusion protein. Spo0J was associated with a region of the nucleoid proximal to the cell pole, both in growing cells dividing symmetrically and in sporulating cells dividing asymmetrically. Additional experiments indicated that Spo0J was bound to sites in the origin-proximal third of the chromosome. These results show that the replicating chromosomes are oriented in a specific manner during the division cycle, with the Spo0J binding region positioned toward the cell poles. Experiments characterizing cells at different stages of the cell cycle showed that chromosome orientation is established prior to the initiation of cell division. Our results indicate that there is a mechanism for orienting the chromosomes and that the chromosome partition protein Spo0J might be part of a bacterial mitotic-like apparatus.
我们通过免疫荧光显微镜检查并观察Spo0J-GFP融合蛋白的荧光，确定了枯草芽孢杆菌染色体分配蛋白Spo0J的亚细胞定位。无论是在对称分裂的生长细胞中还是在不对称分裂的芽孢形成细胞中，Spo0J都与靠近细胞极的类核区域相关联。额外的实验表明，Spo0J与染色体近端三分之一区域的位点结合。这些结果表明，在分裂周期中，复制的染色体以特定方式定向，Spo0J结合区域朝向细胞极。对处于细胞周期不同阶段的细胞进行表征的实验表明，染色体定向在细胞分裂开始之前就已确立。我们的结果表明，存在一种使染色体定向的机制，并且染色体分配蛋白Spo0J可能是细菌类有丝分裂装置的一部分。
