Dinarina Ana, Pugieux Céline, Corral Maria Mora, Loose Martin, Spatz Joachim, Karsenti Eric, Nédélec François
Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg D-69117, Germany.
Cell. 2009 Aug 7;138(3):502-13. doi: 10.1016/j.cell.2009.05.027.
In animal and plant cells, mitotic chromatin locally generates microtubules that self-organize into a mitotic spindle, and its dimensions and bipolar symmetry are essential for accurate chromosome segregation. By immobilizing microscopic chromatin-coated beads on slide surfaces using a microprinting technique, we have examined the effect of chromatin on the dimensions and symmetry of spindles in Xenopus laevis cytoplasmic extracts. While circular spots with diameters around 14-18 microm trigger bipolar spindle formation, larger spots generate an incorrect number of poles. We also examined lines of chromatin with various dimensions. Their length determined the number of poles that formed, with a 6 x 18 microm rectangular patch generating normal spindle morphology. Around longer lines, multiple poles formed and the structures were disorganized. While lines thinner than 10 mum generated symmetric structures, thicker lines induced the formation of asymmetric structures where all microtubules are on the same side of the line. Our results show that chromatin defines spindle shape and orientation. For a video summary of this article, see the PaperFlick file available with the online Supplemental Data.
在动植物细胞中，有丝分裂染色质会在局部产生微管，这些微管会自行组织形成有丝分裂纺锤体，其尺寸和双极对称性对于准确的染色体分离至关重要。通过使用微印刷技术将微观的染色质包被珠固定在载玻片表面，我们研究了染色质对非洲爪蟾细胞质提取物中纺锤体尺寸和对称性的影响。直径约14 - 18微米的圆形斑点会触发双极纺锤体的形成，而较大的斑点会产生数量错误的极。我们还研究了不同尺寸的染色质线。它们的长度决定了形成的极的数量，一个6×18微米的矩形斑块会产生正常的纺锤体形态。在较长的线周围，会形成多个极且结构紊乱。虽然细于10微米的线会产生对称结构，但较粗的线会诱导形成不对称结构，即所有微管都在线的同一侧。我们的结果表明，染色质决定纺锤体的形状和方向。有关本文的视频总结，请参阅在线补充数据中提供的PaperFlick文件。
