Multiple Wnts act synergistically to induce Chk1/Grapes expression and mediate G2 arrest in Drosophila tracheoblasts

  1. Amrutha Kizhedathu
  2. Rose Sebastian Kunnapallill
  3. Archit Bagul
  4. Puja Verma
  5. Arjun Guha  Is a corresponding author
  1. Institute for Stem Cell Biology and Regenerative Medicine (inStem), India
  2. National Center for Biological Sciences, India
  3. Institute of Genetics and Molecular and Cellular Biology, France
  4. Institute for Stem Cell Science and Regenerative Medicine, India

Abstract

Larval tracheae of Drosophila harbor progenitors of the adult tracheal system (tracheoblasts). We showed previously that thoracic tracheoblasts arrest in the G2 phase of the cell cycle in an ATR-Checkpoint Kinase1(Chk1)-dependent manner prior to division and morphogenesis (Kizhedathu et al., 2018). Here we investigate developmental regulation of Chk1 activation. We report that Wnt signaling is high in tracheoblasts and is necessary for high levels of activated (phosphorylated) Chk1. We find that canonical Wnt signaling facilitates this by transcriptional upregulation of Chk1 in cells that have ATR kinase activity. Wnt signalling is dependent on four Wnts (Wg, Wnt5, 6,10) that are expressed at high levels in arrested tracheoblasts and downregulated at mitotic re-entry. Interestingly, none of the Wnts are dispensable and act synergistically to induce Chk1. Finally, we show that downregulation of Wnt signalling and Chk1 expression leads to mitotic re-entry and the concomitant upregulation of Dpp signalling, driving tracheoblast proliferation.

Data availability

All data generated or analysed during this study are included in the manuscript.

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. Rose Sebastian Kunnapallill

    Neurobiology, National Center for Biological Sciences, Bangalore, India
    Competing interests
    The authors declare that no competing interests exist.
  3. Archit Bagul

    Genetics and Molecular and Cellular Biology, Institute of Genetics and Molecular and Cellular Biology, Illkirch-Graffenstaden, France
    Competing interests
    The authors declare that no competing interests exist.
  4. Puja Verma

    Regulation of Cell Fate, Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
    Competing interests
    The authors declare that no competing interests exist.
  5. 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 (inStem Core Grant)

  • Arjun Guha

Department of Biotechnology , Ministry of Science and Technology (InStem Core Grant)

  • 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

Version history

  1. Received: March 20, 2020
  2. Accepted: August 29, 2020
  3. Accepted Manuscript published: September 2, 2020 (version 1)
  4. Accepted Manuscript updated: September 9, 2020 (version 2)
  5. Version of Record published: September 21, 2020 (version 3)
  6. Version of Record updated: September 24, 2020 (version 4)

Copyright

© 2020, 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.

Metrics

  • 1,324
    views
  • 119
    downloads
  • 6
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Amrutha Kizhedathu
  2. Rose Sebastian Kunnapallill
  3. Archit Bagul
  4. Puja Verma
  5. Arjun Guha
(2020)
Multiple Wnts act synergistically to induce Chk1/Grapes expression and mediate G2 arrest in Drosophila tracheoblasts
eLife 9:e57056.
https://doi.org/10.7554/eLife.57056

Share this article

https://doi.org/10.7554/eLife.57056

Further reading

    1. Developmental Biology
    Amrutha Kizhedathu, Archit V Bagul, Arjun Guha
    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.

    1. Cell Biology
    Yi-Ju Chen, Shun-Cheng Tseng ... Eric Hwang
    Research Article

    A functional nervous system is built upon the proper morphogenesis of neurons to establish the intricate connection between them. The microtubule cytoskeleton is known to play various essential roles in this morphogenetic process. While many microtubule-associated proteins (MAPs) have been demonstrated to participate in neuronal morphogenesis, the function of many more remains to be determined. This study focuses on a MAP called HMMR in mice, which was originally identified as a hyaluronan binding protein and later found to possess microtubule and centrosome binding capacity. HMMR exhibits high abundance on neuronal microtubules and altering the level of HMMR significantly affects the morphology of neurons. Instead of confining to the centrosome(s) like cells in mitosis, HMMR localizes to microtubules along axons and dendrites. Furthermore, transiently expressing HMMR enhances the stability of neuronal microtubules and increases the formation frequency of growing microtubules along the neurites. HMMR regulates the microtubule localization of a non-centrosomal microtubule nucleator TPX2 along the neurite, offering an explanation for how HMMR contributes to the promotion of growing microtubules. This study sheds light on how cells utilize proteins involved in mitosis for non-mitotic functions.