Thrower D A, Jordan M A, Wilson L
Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara 93106, USA.
Cell Motil Cytoskeleton. 1996;35(2):121-33. doi: 10.1002/(SICI)1097-0169(1996)35:2<121::AID-CM5>3.0.CO;2-D.
CENP-E is a protein of the kinesin superfamily that appears as small paired globules at kinetochores of chromosomes in mammalian cells during prometaphase and metaphase of mitosis [Yen et al., 1992: Nature 359:536-539]. In the present study we found that a significant number of chromosomes during early prometaphase in HeLa cells (approximately 30%) were stained with a CENP-E antibody in the form of large C-shaped "collars" that partially encircled the chromosomes. The C-shaped CENP-E collars were present only transiently and were completely replaced by small paired globular forms prior to metaphase. Most chromosomes had persistent CENP-E collars in cells blocked at mitosis with a vinblastine concentration sufficient to prevent all microtubule formation. Attachment of newly formed microtubules to the kinetochores after removal of vinblastine resulted in loss of the collars and replacement with small paired globules. Similarly, a higher proportion of chromosomes isolated from vinblastine-treated cells contained CENP-E collars (73%), and the "capture" (i.e., attachment) of microtubules by the chromosomes resulted in conversion of the collars into small paired globules in vitro. Thus, the CENP-E collars form prior to microtubule attachment and disappear after attachment of the chromosomes to the spindle. The CENP-E collars may facilitate capture of microtubules by chromosomes during prometaphase.
着丝粒蛋白E（CENP-E）是驱动蛋白超家族的一种蛋白质，在有丝分裂的前中期和中期，它在哺乳动物细胞染色体的着丝粒处呈现为小的成对球体[Yen等人，1992年：《自然》359：536 - 539]。在本研究中，我们发现，在HeLa细胞有丝分裂早期前中期的大量染色体（约30%）被CENP-E抗体染成大的C形“环”，这些环部分环绕着染色体。C形的CENP-E环仅短暂存在，并在中期之前完全被小的成对球状形式所取代。在以足以阻止所有微管形成的长春花碱浓度阻断有丝分裂的细胞中，大多数染色体有持续的CENP-E环。去除长春花碱后新形成的微管附着到着丝粒上导致环消失并被小的成对球体取代。同样，从长春花碱处理的细胞中分离出的染色体中，含有CENP-E环的比例更高（73%），并且染色体对微管的“捕获”（即附着）在体外导致环转变为小的成对球体。因此，CENP-E环在微管附着之前形成，并在染色体附着到纺锤体后消失。CENP-E环可能在有丝分裂前中期促进染色体对微管的捕获。
