Naslov
Polar kinetochores pivot their way towards the spindle body

Autori
Koprivec, Isabella ; Štimac, Valentina ; Tolić, Iva M.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Skup
Digital Cell Cycle Conference

Mjesto i datum
London, Ujedinjeno Kraljevstvo, 16.06.2021

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Podatak o recenziji nije dostupan

Ključne riječi
Prometaphase ; Congression ; Polar

Sažetak
During mitosis, the cell forms a spindle that equally segregates chromosomes into two daughter cells. Soon after nuclear envelope breakdown, kinetochores on chromosomes are captured by microtubules nucleated at the spindle pole. Some chromosomes immediately find themselves in the area between two spindle poles, yet others positioned at the periphery first need to approach the spindle pole and subsequently travel to the equatorial plane. The question remains how these chromosomes located at the back of the spindle make their way across the centrosome and reach the spindle body, from where they can continue their congression towards the equator. By using confocal and STED live-cell microscopy of SPY- and SiR- tubulin stained RPE1 cells stably expressing CENP- A-GFP and Centrin1-GFP, we demonstrate that polar kinetochores, together with the microtubules they are attached to, pivot around the centrosome towards the spindle body. Pivoting was also evident for microtubules in RPE1 cells stably expressing EYFP-tubulin, where tubulin intensity of astral microtubules decreased over time, as bundles made their way towards the spindle center. The angle that the polar kinetochores form with the spindle axis coincided with rapid spindle elongation, indicating a mechanism in which spindle elongation creates a hydrodynamic drag force that brings kinetochores near the spindle body and enables efficient capture of these kinetochores by spindle body microtubules. This mechanism also ensured timely mitosis, as kinetochores that failed to pivot by the end of spindle elongation significantly delayed anaphase onset. Altogether, we propose a model in which pivoting of microtubules around the spindle pole, driven by spindle elongation, promotes the movement of peripheral chromosomes towards the spindle body and consequently their proper congression to the spindle equator.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

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