Chikashige Yuji, Tsutsumi Chihiro, Yamane Miho, Okamasa Kasumi, Haraguchi Tokuko, Hiraoka Yasushi
Cell Biology Group and CREST Research Project, Kansai Advanced Research Center, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan.
Cell. 2006 Apr 7;125(1):59-69. doi: 10.1016/j.cell.2006.01.048.
In many organisms, meiotic chromosomes are bundled at their telomeres to form a "bouquet" arrangement. The bouquet formation plays an important role in homologous chromosome pairing and therefore progression of meiosis. As meiotic telomere clustering occurs in response to mating pheromone signaling in fission yeast, we looked for factors essential for bouquet formation among genes induced under mating pheromone signaling. This genome-wide search identified two proteins, Bqt1 and Bqt2, that connect telomeres to the spindle-pole body (SPB; the centrosome equivalent in fungi). Neither Bqt1 nor Bqt2 alone functions as a connector, but together the two proteins form a bridge between Rap1 (a telomere protein) and Sad1 (an SPB protein). Significantly, when both Bqt1 and Bqt2 are ectopically expressed in mitotic cells, they also form a bridge between Rap1 and Sad1. Thus, a complex including Bqt1 and Bqt2 is essential for connecting telomeres to the SPB.
在许多生物体中，减数分裂染色体在其端粒处聚集形成“花束”排列。花束形成在同源染色体配对以及减数分裂进程中起着重要作用。由于减数分裂端粒聚集是响应裂殖酵母中的交配信息素信号而发生的，我们在交配信息素信号诱导表达的基因中寻找花束形成所必需的因子。这种全基因组搜索鉴定出了两种蛋白质，Bqt1和Bqt2，它们将端粒连接到纺锤极体（SPB；真菌中相当于中心体的结构）。单独的Bqt1或Bqt2都不能作为连接物发挥作用，但这两种蛋白质共同形成了Rap1（一种端粒蛋白）和Sad1（一种SPB蛋白）之间的桥梁。值得注意的是，当Bqt1和Bqt2在有丝分裂细胞中异位表达时，它们也会在Rap1和Sad1之间形成桥梁。因此，包含Bqt1和Bqt2的复合物对于将端粒连接到SPB至关重要。
