Open Access
CC BY 4.0 · AIMS Genet 2018; 05(02): 141-160
DOI: 10.3934/genet.2018.2.141
Research Article

Non-centrosomal MTs play a crucial role in organization of MT array in interphase fibroblasts

Authors

  • Yekaterina Zvorykina

    1   Biology Department, M.V. Lomonosov Moscow State University, Moscow, Russia
  • Anna Tvorogova

    2   A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
  • Aleena Gladkikh

    1   Biology Department, M.V. Lomonosov Moscow State University, Moscow, Russia
  • I van Vorobjev

    1   Biology Department, M.V. Lomonosov Moscow State University, Moscow, Russia
    2   A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
    3   School of Science and Technology, and National Laboratory Astana, Nazarbayev University, Astana, Kazakhstan

Abstract

Microtubules in interphase fibroblast-like cells are thought to be organized in a radial array growing from a centrosome-based microtubule-organizing center (MTOC) to the cell edges. However, many morphogenetic processes require the asymmetry of the microtubules (MT) array. One of the possible mechanisms of this asymmetry could be the presence of non-centrosomal microtubules in different intracellular areas. To evaluate the role of centrosome-born and non-centrosomal microtubules in the organization of microtubule array in motile 3T3 fibroblasts, we have performed the high-throughput analysis of microtubule growth in different functional zones of the cell and distinguished three subpopulations of growing microtubules (centrosome-born, marginal and inner cytoplasmic).

Centrosome as an active microtubule-organizing center was absent in half of the cell population. However, these cells do not show any difference in microtubule growth pattern. In cells with active centrosome, it was constantly forming short (ephemeral) MTs, and ∼15–20 MT per minute grow outwards for a distance >1 µm. Almost no persistent growth of microtubules was observed in these cells with the average growth length of 5–6 µm and duration of growth periods within 30 s.

However, the number of growing ends increased towards cell margin, especially towards the active edges. We found the peripheral cytoplasmic foci of microtubule growth there. During recovery from nocodazole treatment microtubules started to grow around the centrosome in a normal way and independently in all the cell areas. Within 5 minutes microtubules continued to grow mainly near the cell edge. Thus, our data confirm the negligible role of centrosome as MTOC in 3T3 fibroblasts and propose a model of non-centrosomal microtubules as major players that create the cell asymmetry in the cells with a mesenchymal type of motility. We suggest that increased density of dynamic microtubules near the active lamellum could be supported by microtubule-based microtubule nucleation.



Publication History

Received: 05 December 2017

Accepted: 15 March 2018

Article published online:
10 May 2021

© 2018. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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