Orthaus Sandra, Ohndorf Sabine, Diekmann Stephan
Department of Molecular Biology, FLI e.V., Beutenbergstrasse 11, D-07745 Jena, Germany.
Biochem Biophys Res Commun. 2006 Sep 15;348(1):36-46. doi: 10.1016/j.bbrc.2006.06.187. Epub 2006 Jul 27.
The inner kinetochore protein complex binds to centromeres during the whole cell cycle. It serves as the basis for the binding of further kinetochore proteins during mitosis. CENP-H is one of the inner kinetochore proteins which is conserved amongst many eukaryotes. By specific RNAi knockdown, we reduced the CENP-H protein level in human HEp-2 cells down to less than 5% of its normal value. In these CENP-H knocked-down cells, we observed severe mitotic phenotypes like misaligned chromosomes and multipolar spindles, however, no mitotic arrest. Strong reduction of CENP-H resulted in a slightly reduced CENP-C level at the kinetochores and normal localisation of hBubR1, indicating a functional mitotic checkpoint at the hBubR1 protein level. In CENP-H knocked-down human cells, the misaligned chromosomes contained only reduced levels of CENP-E. Our data clearly indicate that CENP-H has an important impact on the architecture and function of the human kinetochore complex.
着丝粒内侧蛋白复合体在整个细胞周期中都与着丝粒结合。它是有丝分裂期间进一步结合着丝粒蛋白的基础。CENP-H是一种着丝粒内侧蛋白，在许多真核生物中都保守存在。通过特异性RNA干扰敲低，我们将人HEp-2细胞中的CENP-H蛋白水平降低至其正常值的5%以下。在这些CENP-H敲低的细胞中，我们观察到了严重的有丝分裂表型，如染色体排列异常和多极纺锤体，但没有有丝分裂停滞。CENP-H的强烈降低导致着丝粒处CENP-C水平略有降低，且hBubR1定位正常，这表明在hBubR1蛋白水平存在功能性的有丝分裂检查点。在CENP-H敲低的人细胞中，排列异常的染色体仅含有降低水平的CENP-E。我们的数据清楚地表明，CENP-H对人着丝粒复合体的结构和功能有重要影响。
