Kim Sunghwan, Lee Kwanwoo, Rhee Kunsoo
Department of Biological Sciences and Research Center for Functional Cellulomics, Seoul National University, Seoul 151-742, Republic of Korea.
Biochem Biophys Res Commun. 2007 Aug 17;360(1):56-62. doi: 10.1016/j.bbrc.2007.05.206. Epub 2007 Jun 8.
NIMA in Aspergillus nidulans is a mitotic kinase for chromosome condensation and segregation. We characterized NEK7, a human homologue of Aspergillus NIMA. NEK7 was located at the centrosome throughout the cell cycle. Temporal localization of NEK7 at midbody of the cytokinetic cell was also observed. NEK7 knockdown by RNAi caused a prometaphase arrest of the cell cycle with monopolar or disorganized spindle. We propose that such defects in spindle assembly are resulted from reduction in microtubule nucleation activity at the centrosome. In consistent to the proposal, we observed a decrease in the centrosomal gamma-tubulin levels and reduction of the microtubule re-growth activity in the NEK7-suppressed cells. In addition, it was evident that NEK7 was directly involved in cytokinesis.
构巢曲霉中的NIMA是一种用于染色体凝聚和分离的有丝分裂激酶。我们对曲霉NIMA的人类同源物NEK7进行了表征。NEK7在整个细胞周期中都位于中心体。还观察到NEK7在细胞分裂细胞的中体处的时间定位。RNAi介导的NEK7敲低导致细胞周期前中期停滞，纺锤体呈单极或紊乱状态。我们认为，纺锤体组装中的此类缺陷是由于中心体微管成核活性降低所致。与该提议一致，我们观察到NEK7抑制细胞中中心体γ-微管蛋白水平降低，微管重新生长活性降低。此外，很明显NEK7直接参与胞质分裂。
