Tang Xie, Jin Ye, Cande W Zacheus
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
J Cell Biol. 2006 Jun 19;173(6):845-51. doi: 10.1083/jcb.200602152. Epub 2006 Jun 12.
The telomere bouquet, i.e., telomere clustering on the nuclear envelope (NE) during meiotic prophase, is thought to promote homologous chromosome pairing. Using a visual screen, we identified bqt2/im295, a mutant that disrupts telomere clustering in fission yeast. Bqt2p is required for linking telomeres to the meiotic spindle pole body (SPB) but not for attachment of telomeres or the SPB to the NE. Bqt2p is expressed upon pheromone sensing and colocalizes thereafter to Sad1p, an SPB protein. This localization only depends on Bqt1p, not on other identified proteins required for telomere clustering. Upon pheromone sensing, generation of Sad1p foci next to telomeres depends on Bqt2p. However, depletion of Bqt2p from the SPB is dispensable for dissolving the telomere bouquet at the end of meiotic prophase. Therefore, telomere bouquet formation requires Bqt2p as a linking component and is finely regulated during meiotic progression.
端粒花束，即在减数分裂前期核膜（NE）上的端粒聚集，被认为可促进同源染色体配对。通过视觉筛选，我们鉴定出了bqt2/im295，这是一种破坏裂殖酵母中端粒聚集的突变体。Bqt2p是将端粒连接到减数分裂纺锤体极体（SPB）所必需的，但不是端粒或SPB附着到NE所必需的。Bqt2p在感知信息素时表达，随后与SPB蛋白Sad1p共定位。这种定位仅取决于Bqt1p，而不取决于其他已鉴定的端粒聚集所需蛋白。在感知信息素时，端粒旁Sad1p焦点的产生取决于Bqt2p。然而，在减数分裂前期结束时，从SPB中去除Bqt2p对于溶解端粒花束是可有可无的。因此，端粒花束的形成需要Bqt2p作为连接成分，并且在减数分裂过程中受到精细调节。
