Genetic Control of Kinetochore-Driven Microtubule Growth in Drosophila Mitosis

  • Julia V. Popova
  • , Gera A. Pavlova
  • , Alyona V. Razuvaeva
  • , Lyubov A. Yarinich
  • , Evgeniya N. Andreyeva
  • , Alina F. Anders
  • , Yuliya A. Galimova
  • , Fioranna Renda
  • , Maria Patrizia Somma
  • , Alexey V. Pindyurin
  • , Maurizio Gatti

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Centrosome-containing cells assemble their spindles exploiting three main classes of microtubules (MTs): MTs nucleated by the centrosomes, MTs generated near the chromosomes/kinetochores, and MTs nucleated within the spindle by the augmin-dependent pathway. Mammalian and Drosophila cells lacking the centrosomes generate MTs at kinetochores and eventually form functional bipolar spindles. However, the mechanisms underlying kinetochore-driven MT formation are poorly understood. One of the ways to elucidate these mechanisms is the analysis of spindle reassembly following MT depolymerization. Here, we used an RNA interference (RNAi)-based reverse genetics approach to dissect the process of kinetochore-driven MT regrowth (KDMTR) after colcemid-induced MT depolymerization. This MT depolymerization procedure allows a clear assessment of KDMTR, as colcemid disrupts centrosome-driven MT regrowth but not KDMTR. We examined KDMTR in normal Drosophila S2 cells and in S2 cells subjected to RNAi against conserved genes involved in mitotic spindle assembly: mast/orbit/chb (CLASP1), mei-38 (TPX2), mars (HURP), dgt6 (HAUS6), Eb1 (MAPRE1/EB1), Patronin (CAMSAP2), asp (ASPM), and Klp10A (KIF2A). RNAi-mediated depletion of Mast/Orbit, Mei-38, Mars, Dgt6, and Eb1 caused a significant delay in KDMTR, while loss of Patronin had a milder negative effect on this process. In contrast, Asp or Klp10A deficiency increased the rate of KDMTR. These results coupled with the analysis of GFP-tagged proteins (Mast/Orbit, Mei-38, Mars, Eb1, Patronin, and Asp) localization during KDMTR suggested a model for kinetochore-dependent spindle reassembly. We propose that kinetochores capture the plus ends of MTs nucleated in their vicinity and that these MTs elongate at kinetochores through the action of Mast/Orbit. The Asp protein binds the MT minus ends since the beginning of KDMTR, preventing excessive and disorganized MT regrowth. Mei-38, Mars, Dgt6, Eb1, and Patronin positively regulate polymerization, bundling, and stabilization of regrowing MTs until a bipolar spindle is reformed.

Original languageEnglish (US)
Article number2127
JournalCells
Volume11
Issue number14
DOIs
StatePublished - Jul 1 2022

Keywords

  • Asp
  • Dgt6
  • Drosophila
  • Eb1
  • Klp10A
  • Mars
  • Mast/Orbit/Chb
  • Mei-38
  • Patronin
  • S2 cells
  • colcemid
  • kinetochores
  • microtubule depolymerization
  • microtubule regrowth
  • mitosis

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology

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