Centrioles in the cell cycle. I. Epithelial cells.

Abstract

A study was made of the structure of the centrosome in the cell cycle in a nonsynchronous culture of pig kidney embryo (PE) cells. In the spindle pole of the metaphase cell there are two mutually perpendicular centrioles (mother and daughter) which differ in their ultrastructure . An electron-dense halo, which surrounds only the mother centriole and is the site where spindle microtubules converge, disappears at the end of telophase. In metaphase and anaphase, the mother centriole is situated perpendicular to the spindle axis . At the beginning of the G, period, pericentriolar satellites are formed on the mother centriole with microtubules attached to them ; the two centrioles diverge. The structures of the two centrioles differ throughout interphase ; the mother centriole has appendages, the daughter does not. Replication of the centrioles occurs approximately in the middle of the S period . The structure of the procentrioles differs sharply from that of the mature centriole. Elongation of procentrioles is completed in prometaphasé, and their structure undergoes a number of successive changes. In the G2 period, pericentriolar satellites disappear and some time later a fibrillar halo is formed on both mother centrioles, i .e ., spindle poles begin to form . In the cells that have left the mitotic cycle (Go period), replication of centrioles does not take place; in many cells, a cilium is formed on the mother centriole. In a small number of cells a cilium is formed in the S and G2 periods, but unlike the cilium in the Go period it does not reach the surface of the cell . In all cases, it locates on the centriole with appendages . At the beginning of the G, period, during the G2 period, and in nonciliated cells in the Go period, one of the centrioles is situated perpendicular to the substrate. On the whole, it takes a mature centriole a cycle and a half to form in PE cells.The behavior of centrioles in the cell cycle has been described in a number of works (13,21,22,24,29,30), but the majority of authors have confined themselves to a description of some individual cycle phases rather than making a comprehensive analysis of all the periods of interphase and mitosis . The emphasis in these works is on the location of centrioles in the cell and on the time of their duplication, whereas the interaction between interphase centrioles and cytoplasmic microtubules and the dynamics of all centrosome structures are hardly mentioned . Very little is known about the structure of the growing centriole in unciliated cells from the moment of its emergence near the mother centriole. Of great interest is the verification of the assumption about the oriented location of centrioles in mitosis and interphase.In the present work we have tried to elucidate the changes in centriole structure and general composition of the centriolar apparatus during and at completion of the mitotic cycle. The method was essentially as follows: we marked the individual cell under the light microscope and then examined the serial sections of this ...

Centrosome behaviour and orientation of centrioles under the action of energy transfer inhibitors.

“…In non-synchronized culture of PK cells-orientation of active centrioles to the substrate surface is close to the random one (Vorobjev and Chentsov, 1982). In our experiments the non-random (preferentially perpendicular) orientation of active centrioles appeared under DNP and ouabain treatment.…”

“…The perpendicular orientation of active centrioles to the substrate surface has been described previously for PK cells spreading after mitosis (Vorobjev and Chentsov, 1982) and for mouse embryo fibroblasts when seeded on to a coverslip surface (Gudima et al 1983). In non-synchronized culture of PK cells-orientation of active centrioles to the substrate surface is close to the random one (Vorobjev and Chentsov, 1982).…”

“…For the electron microscopic study, cells were prepared as described previously (Vorobjev and Chentsov, 1982). Cells grown on cover slips were fixed with 2.5% glutaraldehyde, postfixed with osmium tetroxide, stained with uranium acetate, dehydrated and embedded in Epon 812 mixture.…”

Structure and microtubule-nucleation activity of isolated Drosophila embryo centrosomes characterized by whole mount scanning and transmission electron microscopy

“…We interpret the abundant pericentriolar material together with the high number of nucleated microtubules as a marker of mitotic centrosomes (Khodjakov and Rieder 1999;Rieder and Borisy 1982;Vorobjev and Chentsov YuS 1982). This is also concomitant with the presence of MPM2 phosphoepitopes (Logarinho and Sunkel 1998) also detected in most of our centrosomes (see also Fig.…”

Localization of kinesin in cultured cells.

“…All PtK~ cells examined showed this component, and multinuclear or polyploid cells in the cultures usually contained more than one such structure. On the basis of their size, shape, and position, we interpret the kinesin-positive fibers as primary cilia, the nonmotile axonemes that frequently grow from the mother centriole of interphase cells in culture (1,15,39). The interphase cytoplasm also shows a faint fibrous and reticular staining with the anti-bovine kinesin antibodies.…”