Duox generated reactive oxygen species activate ATR/Chk1 to induce G2 arrest in Drosophila tracheoblasts

  1. Amrutha Kizhedathu
  2. Piyush Chhajed
  3. Lahari Yeramala
  4. Deblina Sain Basu
  5. Tina Mukherjee
  6. Vinothkumar R Kutti
  7. Arjun Guha  Is a corresponding author
  1. Institute for Stem Cell Biology and Regenerative Medicine (inStem), India
  2. National Centre for Biological Sciences, Iceland
  3. National Centre for Biological Sciences, India

Abstract

Progenitors of the thoracic tracheal system of adult Drosophila (tracheoblasts) arrest in G2 during larval life and rekindle a mitotic program subsequently. G2 arrest is dependent on ATR-dependent phosphorylation of Chk1 that is actuated in the absence of detectable DNA damage. We are interested in the mechanisms that activate ATR/Chk1 (Kizhedathu et al., 2018, 2020). Here we report that levels of reactive oxygen species (ROS) are high in arrested tracheoblasts and decrease upon mitotic re-entry. High ROS is dependent on expression of Duox, an H2O2 generating-Dual Oxidase. ROS quenching by overexpression of Superoxide Dismutase 1, or by knockdown of Duox, abolishes Chk1 phosphorylation and results in precocious proliferation. Tracheae deficient in Duox, or deficient in both Duox and regulators of DNA damage-dependent ATR/Chk1 activation (ATRIP/TOPBP1/ Claspin), can induce phosphorylation of Chk1 in response to micromolar concentrations of H2O2 in minutes. The findings presented reveal that H2O2 activates ATR/Chk1 in tracheoblasts by a non-canonical, potentially direct, mechanism.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting file; Source Data files have been provided for Figures 1,2,3,4

Article and author information

Author details

  1. Amrutha Kizhedathu

    Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore, India
    Competing interests
    The authors declare that no competing interests exist.
  2. Piyush Chhajed

    Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore, India
    Competing interests
    The authors declare that no competing interests exist.
  3. Lahari Yeramala

    National Centre for Biological Sciences, Bangalore, Iceland
    Competing interests
    The authors declare that no competing interests exist.
  4. Deblina Sain Basu

    Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore, India
    Competing interests
    The authors declare that no competing interests exist.
  5. Tina Mukherjee

    Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore, India
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3776-5536
  6. Vinothkumar R Kutti

    Biochemistry, Biophysics and Bioinformatics, National Centre for Biological Sciences, Bangalore, India
    Competing interests
    The authors declare that no competing interests exist.
  7. Arjun Guha

    Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore, India
    For correspondence
    arjung@instem.res.in
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3753-1484

Funding

Department of Biotechnology, Ministry of Science and Technology, India (inStem Core Funds)

  • Arjun Guha

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Amin S. Ghabrial, Columbia University, United States

Publication history

  1. Received: March 24, 2021
  2. Preprint posted: March 25, 2021 (view preprint)
  3. Accepted: October 7, 2021
  4. Accepted Manuscript published: October 8, 2021 (version 1)
  5. Accepted Manuscript updated: October 11, 2021 (version 2)
  6. Version of Record published: November 16, 2021 (version 3)

Copyright

© 2021, Kizhedathu et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Amrutha Kizhedathu
  2. Piyush Chhajed
  3. Lahari Yeramala
  4. Deblina Sain Basu
  5. Tina Mukherjee
  6. Vinothkumar R Kutti
  7. Arjun Guha
(2021)
Duox generated reactive oxygen species activate ATR/Chk1 to induce G2 arrest in Drosophila tracheoblasts
eLife 10:e68636.
https://doi.org/10.7554/eLife.68636

Further reading

    1. Developmental Biology
    Amrutha Kizhedathu et al.
    Research Article Updated

    Imaginal progenitors in Drosophila are known to arrest in G2 during larval stages and proliferate thereafter. Here we investigate the mechanism and implications of G2 arrest in progenitors of the adult thoracic tracheal epithelium (tracheoblasts). We report that tracheoblasts pause in G2 for ~48–56 h and grow in size over this period. Surprisingly, tracheoblasts arrested in G2 express drivers of G2-M like Cdc25/String (Stg). We find that mechanisms that prevent G2-M are also in place in this interval. Tracheoblasts activate Checkpoint Kinase 1/Grapes (Chk1/Grp) in an ATR/mei-41-dependent manner. Loss of ATR/Chk1 led to precocious mitotic entry ~24–32 h earlier. These divisions were apparently normal as there was no evidence of increased DNA damage or cell death. However, induction of precocious mitoses impaired growth of tracheoblasts and the tracheae they comprise. We propose that ATR/Chk1 negatively regulate G2-M in developing tracheoblasts and that G2 arrest facilitates cellular and hypertrophic organ growth.

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    Today septins are considered as the fourth component of the cytoskeleton, with the Septin7 isoform playing a critical role in the formation of higher-order structures. While its importance has already been confirmed in several intracellular processes of different organs, very little is known about its role in skeletal muscle. Here, using Septin7 conditional knockdown (KD) mouse model, the C2C12 cell line, and enzymatically isolated adult muscle fibers, the organization and localization of septin filaments are revealed, and an ontogenesis-dependent expression of Septin7 is demonstrated. KD mice displayed a characteristic hunchback phenotype with skeletal deformities, reduction in in vivo and in vitro force generation, and disorganized mitochondrial networks. Furthermore, knockout of Septin7 in C2C12 cells resulted in complete loss of cell division while KD cells provided evidence that Septin7 is essential for proper myotube differentiation. These and the transient increase in Septin7 expression following muscle injury suggest that it may be involved in muscle regeneration and development.