The collapse of the spindle following ablation in S. pombe is mediated by microtubules and the motor protein dynein

Parsa Zareiesfandabadi, Mary Williard Elting

Posted on: 24 June 2021 , updated on: 16 August 2023

Preprint posted on 20 May 2021

Article now published in Biophysical Journal at

Ablating the microtubule spindle during cell division causes it to collapse. Zareiesfandabadi et. al. show how the minus-end directed motor protein dynein, plays a role in this collapse.

Selected by Leeba Ann Chacko

Categories: cell biology, microbiology


Schematic depicting the collapse of the spindle after laser ablation which is aided partially by dynein.

Unlike many of their mammalian counterparts, fission yeasts are unicellular eukaryotes that undergo ‘closed mitosis’, where the nuclear envelope does not undergo breakdown during cell division. Instead, at the onset of mitosis, cytoplasmic microtubules are reorganized to form the mitotic spindle within the closed nucleus1. This spindle elongates inside the nucleus causing it to expand and in the process, the DNA from the mother cell is equally distributed into identical daughter cells.

Scientists have wondered whether the nucleus and/or its contents can exert an opposing force to the elongating spindle. Previous work has shown that ablating the mitotic spindle with a laser causes the spindle to collapse2,3.  This collapse was suggested to occur due to passive viscoelastic relaxation of the nucleus and/or mechanical relaxation of stretched chromosomes. However, in this preprint, Zareiesfandabadi et. al. show that active forces driven by dynein contribute to the collapse of the spindle.

Dynein is known to aid chromosome biorientation to enable its proper segregation in fission yeast4,5. Here, Zareiesfandabadi et. al. demonstrate dynein’s role in ensuring mechanical force balance in the spindle through its ability to slide antiparallel microtubules towards each other as the spindle elongates in the opposite direction.

Key results:

Zareiesfandabadi et. al. used the technique of laser ablation to split the spindle in the middle to identify the forces being exerted on the broken, collapsing spindles.

Upon ablating the spindle, they showed that the collapse observed post-laser ablation follows an exponential relaxation response. While this observation is consistent with viscoelastic relaxation, it did not explain the observed spindle rotation within the nucleus. To test whether active forces are at play, the authors examined how much passive nuclear and chromosomal relaxation forces contribute to spindle collapse.

The authors found that upon ablating the early-stage, short spindle, the separated spindles collapsed towards each other while the chromosomes remained largely stationary. Contrastingly, when ablating the later-stage, long spindle, the chromosomes moved along with the collapsing spindle. Interestingly, the authors observed inward indentations in regions of the chromosome that were connected to the spindle ends. Similarly, there were inward indentations on the surface of the nuclear envelope that was in close proximity to the spindle ends. Based on these results, the authors concluded that neither mechanical relaxation of chromosomes nor viscoelastic relaxation of the nucleus contributed to the collapse of the spindle.

The authors determined that while actin plays no role in spindle collapse, microtubule dynamics are necessary for spindle collapse. They found that the minus end-directed motor protein, dynein, aids spindle collapse.  In the absence of dynein, the spindle opts for a prolonged rotational diffusion instead of exhibiting a relaxation response. From this, the authors concluded that the observed collapse of the spindle post-ablation is partially mediated by active forces from dynein and microtubule polymerization.

What I liked about this preprint:

What stood out most for me was the elegance and simplicity of the experiments that were used to test the hypothesis. The authors were able to uncover substantial molecular dynamics using the well-known technique of laser ablation. These experiments reiterate the importance of devoting time towards analyzing data extensively so that one does not miss out on discoveries like the inward indentations the authors observed.


1. Mehta, K., et al., Association of mitochondria with microtubules inhibits mitochondrial fission by precluding assembly of the fission protein Dnm1. J Biol Chem, 2019. 294(10): p. 3385-3396.

2. Khodjakov, A., S. La Terra, and F. Chang, Laser microsurgery in fission yeast; role of the mitotic spindle midzone in anaphase B. Curr Biol, 2004. 14(15): p. 1330-40.

3. Tolic-Norrelykke, I.M., et al., Positioning and elongation of the fission yeast spindle by microtubule-based pushing. Curr Biol, 2004. 14(13): p. 1181-6.

4. Grishchuk, E.L., I.S. Spiridonov, and J.R. McIntosh, Mitotic chromosome biorientation in fission yeast is enhanced by dynein and a minus-end-directed, kinesin-like protein. Mol Biol Cell, 2007. 18(6): p. 2216-25.

5. Courtheoux, T., et al., Dynein participates in chromosome segregation in fission yeast. Biol Cell, 2007. 99(11): p. 627-37.

6. Schreiner, S.M., et al., The tethering of chromatin to the nuclear envelope supports nuclear mechanics. Nat Commun, 2015. 6: p. 7159.

Tags: fission yeast, laser ablation, microtubule, mitosis, s.pombe, spindle


Read preprint (No Ratings Yet)

Author's response

Mary Williard Elting and Parsa Zareiesfandabadi shared

1. To completely rule out the possibility of viscoelastic forces from nuclear relaxation, would it be useful to see whether spindle collapse increases when the nuclear rigidity is lowered? Mutants in which the chromatin is untethered from the inner nuclear membrane exhibit deformable nuclei6. Perhaps these mutants could be used to test this?

This is a good follow-up experiment. It is conceivable that if the collapse speed were unchanged when the rigidity of NE is lowered, one could rule out the contribution of relaxation of the NE during the collapse. A change in collapse speed would also provide information on the nuclear envelope relaxation. What we know so far is that, as Figure 3D of the papers indicates, we did not find a different collapse for smalls vs. large spindles in wild-type cells, which was surprising since the elongated NE is thought to be at higher tension than the spherical stage NE. In new data (not in the preprint), we’ve also begun to examine the collapse where the spindle pole bodies were not tethered to the NE using a pkl1 deletion strain and did not detect a different collapse. But we agree with you that untethering chromatin would also be a way to get at this question in more depth.

2. Do you expect to see an increase in spindle collapse upon over-expressing dynein in the cells?

Great questions, and while that is an appealing idea, we think it’s hard to predict whether overexpressing would necessarily increase the collapse amount or rate. The reason is that dynein overexpression would not necessarily ensure more force generation on the spindle fragment (since we don’t know how it’s recruited), and it’s also possible that dynein overexpression could cause crowding of the microtubules, acting to effectively increase friction and actually slowing collapse. Even though we cannot reliably predict the outcome of overexpression of dynein, we agree that it would certainly be an interesting follow-up experiment. It also would likely help us identify where the dynein is during the collapse, a question that is still open.

3. Would it be feasible to observe the dynein localization during spindle collapse? Perhaps this could provide further insight into the precise mechanism through which dynein is able to pull the spindle inward?

Good question! We have not localized dynein and so we don’t know for sure where it’s localized or exactly how it enables collapse. This is an experiment that we’re very excited to try in the future!

We presume that the two half-spindles need to connect to generate a shortening force, though we don’t know how yet. Our mental model has been that perhaps dynein localizes to the new microtubule minus-ends (of each side of the cut spindle) and then pulls the poles toward each other by dragging one fragment along the other. A similar response to ablation is seen by dynein in severed spindle fibers in mammalian (see Elting and Hueschen, JCB 2014). However, that’s very much speculation at this point, and something we need to follow up on.

4. While it is known that dynein plays various roles during fission yeast meiosis, do you think dynein provides mechanical force balance to the spindle during meiosis I and II as well?

That is an intriguing question and one we have thought of but have not had the time to conduct. As the question mentions, dynein is known to be important for meiotic prophase in S. pombe – specifically for nuclear oscillations during this phase, through its localization at SPBs and astral microtubules (Yamamoto et al, JCB 1999). In contrast, dynein deletion does not affect normal spindle dynamics in mitosis, although it does cause a small defect in chromosome biorientation4,5. It has been proposed that this function is achieved through spindle microtubule bundling and/or anchoring at SPBs, a role that dynein performs in many other cell types. The data in our preprint are certainly consistent with this mitotic interpretation, though we have not yet localized or precisely identified the population of dynein contributing to spindle collapse. As for meiosis – the geometry (and thus the mechanics) of the S. pombe meiotic spindle are somewhat different than the mitotic spindle, so it’s hard to say whether dynein is playing the same role there or not (in addition to its known role in meiotic nuclear alignment). That said, we agree that this would be an interesting follow-up to our work!

Have your say

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Sign up to customise the site to your preferences and to receive alerts

Register here

Also in the cell biology category:

Control of Inflammatory Response by Tissue Microenvironment

Zhongyang Wu, Scott D. Pope, Nasiha S. Ahmed, et al.

Selected by 13 June 2024

Roberto Amadio


Notch3 is a genetic modifier of NODAL signalling for patterning asymmetry during mouse heart looping

Tobias Holm Bønnelykke, Marie-Amandine Chabry, Emeline Perthame, et al.

Selected by 06 June 2024

Bhaval Parmar

Developmental Biology

LINC complex alterations are a hallmark of sporadic and familial ALS/FTD

Riccardo Sirtori, Michelle Gregoire, Emily Potts, et al.

Selected by 03 June 2024

Megane Rayer et al.

Cell Biology

Also in the microbiology category:

Characterization of natural product inhibitors of quorum sensing in Pseudomonas aeruginosa reveals competitive inhibition of RhlR by ortho-vanillin

Kathryn E. Woods, Sana Akhter, Blanca Rodriguez, et al.

Selected by 22 May 2024

UofA IMB565 et al.


Feedback loop regulation between viperin and viral hemorrhagic septicemia virus through competing protein degradation pathways

Xiaobing Lu, Meisheng Yi, Zhe Hu, et al.

Selected by 21 May 2024

UofA IMB565 et al.


Lytic bacteriophages interact with respiratory epithelial cells and induce the secretion of antiviral and proinflammatory cytokines

Paula F. Zamora, Thomas G. Reidy, Catherine R. Armbruster, et al.

Selected by 20 May 2024

UofA IMB565 et al.


preLists in the cell biology category:

BSCB-Biochemical Society 2024 Cell Migration meeting

This preList features preprints that were discussed and presented during the BSCB-Biochemical Society 2024 Cell Migration meeting in Birmingham, UK in April 2024. Kindly put together by Sara Morais da Silva, Reviews Editor at Journal of Cell Science.


List by Reinier Prosee

‘In preprints’ from Development 2022-2023

A list of the preprints featured in Development's 'In preprints' articles between 2022-2023


List by Alex Eve, Katherine Brown

preLights peer support – preprints of interest

This is a preprint repository to organise the preprints and preLights covered through the 'preLights peer support' initiative.


List by preLights peer support

The Society for Developmental Biology 82nd Annual Meeting

This preList is made up of the preprints discussed during the Society for Developmental Biology 82nd Annual Meeting that took place in Chicago in July 2023.


List by Joyce Yu, Katherine Brown

CSHL 87th Symposium: Stem Cells

Preprints mentioned by speakers at the #CSHLsymp23


List by Alex Eve

Journal of Cell Science meeting ‘Imaging Cell Dynamics’

This preList highlights the preprints discussed at the JCS meeting 'Imaging Cell Dynamics'. The meeting was held from 14 - 17 May 2023 in Lisbon, Portugal and was organised by Erika Holzbaur, Jennifer Lippincott-Schwartz, Rob Parton and Michael Way.


List by Helen Zenner

9th International Symposium on the Biology of Vertebrate Sex Determination

This preList contains preprints discussed during the 9th International Symposium on the Biology of Vertebrate Sex Determination. This conference was held in Kona, Hawaii from April 17th to 21st 2023.


List by Martin Estermann

Alumni picks – preLights 5th Birthday

This preList contains preprints that were picked and highlighted by preLights Alumni - an initiative that was set up to mark preLights 5th birthday. More entries will follow throughout February and March 2023.


List by Sergio Menchero et al.

CellBio 2022 – An ASCB/EMBO Meeting

This preLists features preprints that were discussed and presented during the CellBio 2022 meeting in Washington, DC in December 2022.


List by Nadja Hümpfer et al.


The advances in fibroblast biology preList explores the recent discoveries and preprints of the fibroblast world. Get ready to immerse yourself with this list created for fibroblasts aficionados and lovers, and beyond. Here, my goal is to include preprints of fibroblast biology, heterogeneity, fate, extracellular matrix, behavior, topography, single-cell atlases, spatial transcriptomics, and their matrix!


List by Osvaldo Contreras

EMBL Synthetic Morphogenesis: From Gene Circuits to Tissue Architecture (2021)

A list of preprints mentioned at the #EESmorphoG virtual meeting in 2021.


List by Alex Eve

FENS 2020

A collection of preprints presented during the virtual meeting of the Federation of European Neuroscience Societies (FENS) in 2020


List by Ana Dorrego-Rivas

Planar Cell Polarity – PCP

This preList contains preprints about the latest findings on Planar Cell Polarity (PCP) in various model organisms at the molecular, cellular and tissue levels.


List by Ana Dorrego-Rivas

BioMalPar XVI: Biology and Pathology of the Malaria Parasite

[under construction] Preprints presented at the (fully virtual) EMBL BioMalPar XVI, 17-18 May 2020 #emblmalaria


List by Dey Lab, Samantha Seah


Cell Polarity

Recent research from the field of cell polarity is summarized in this list of preprints. It comprises of studies focusing on various forms of cell polarity ranging from epithelial polarity, planar cell polarity to front-to-rear polarity.


List by Yamini Ravichandran

TAGC 2020

Preprints recently presented at the virtual Allied Genetics Conference, April 22-26, 2020. #TAGC20


List by Maiko Kitaoka et al.

3D Gastruloids

A curated list of preprints related to Gastruloids (in vitro models of early development obtained by 3D aggregation of embryonic cells). Updated until July 2021.


List by Paul Gerald L. Sanchez and Stefano Vianello

ECFG15 – Fungal biology

Preprints presented at 15th European Conference on Fungal Genetics 17-20 February 2020 Rome


List by Hiral Shah

ASCB EMBO Annual Meeting 2019

A collection of preprints presented at the 2019 ASCB EMBO Meeting in Washington, DC (December 7-11)


List by Madhuja Samaddar et al.

EMBL Seeing is Believing – Imaging the Molecular Processes of Life

Preprints discussed at the 2019 edition of Seeing is Believing, at EMBL Heidelberg from the 9th-12th October 2019


List by Dey Lab


Preprints on autophagy and lysosomal degradation and its role in neurodegeneration and disease. Includes molecular mechanisms, upstream signalling and regulation as well as studies on pharmaceutical interventions to upregulate the process.


List by Sandra Malmgren Hill

Lung Disease and Regeneration

This preprint list compiles highlights from the field of lung biology.


List by Rob Hynds

Cellular metabolism

A curated list of preprints related to cellular metabolism at Biorxiv by Pablo Ranea Robles from the Prelights community. Special interest on lipid metabolism, peroxisomes and mitochondria.


List by Pablo Ranea Robles

BSCB/BSDB Annual Meeting 2019

Preprints presented at the BSCB/BSDB Annual Meeting 2019


List by Dey Lab


This list of preprints is focused on work expanding our knowledge on mitochondria in any organism, tissue or cell type, from the normal biology to the pathology.


List by Sandra Franco Iborra

Biophysical Society Annual Meeting 2019

Few of the preprints that were discussed in the recent BPS annual meeting at Baltimore, USA


List by Joseph Jose Thottacherry

ASCB/EMBO Annual Meeting 2018

This list relates to preprints that were discussed at the recent ASCB conference.


List by Dey Lab, Amanda Haage