Ascidian development and cytoplasmic reorganizations: dissecting the mechanisms that pattern developmental determinants and shape embryonic development

Project Information

ACRO

Grant agreement ID: 101031780

DOI

10.3030/101031780

Project terminated on 30 June 2021

EC signature date 18 February 2021

Start date 1 March 2021

End date 28 February 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 174 167,04

EU contribution

€ 174 167,04

Coordinated by

INSTITUTE OF SCIENCE AND TECHNOLOGY AUSTRIA
Austria

Periodic Reporting for period 1 - ACRO (Ascidian development and cytoplasmic reorganizations: dissecting the mechanisms that pattern developmental determinants and shape embryonic development)

Reporting period: 2021-03-01 to 2023-02-28

Summary of the context and overall objectives of the project

In many animals, the asymmetries that underlie the specification of the body axes are established in the fertilized egg. For example, in frog and ascidian eggs, fertilization triggers massive cytoskeletal-dependent reorganizations of the cytosol to asymmetrically pattern developmental determinants along the prospective body axes. Thus, to understand axis specification, we must elucidate how cytoskeletal forces are organized in space and time and how eggs harness these forces to establish polarity.
Despite its critical role in determining cell fate, remarkably little is known about the mechanisms that orchestrate cytoplasmic reorganization and the distribution of maternal factors in ascidians. The overall aim of this proposal was to elucidate the molecular, cellular, and biophysical processes that drive cytoplasmic reorganization and how cytoplasmic reorganization determines the localization of maternal factors that pattern the developing embryo.
This project employed high-resolution microscopy, force and cell shape manipulations, and proximity biotinylation to address the following fundamental questions:
1) What are the microtubule-dependent mechanisms that regulate cytoplasmic reorganization
and anterior-posterior polarity in the ascidian egg?
2) How does cytoplasmic reorganization control the precise positioning of developmental determinants?
This study will shed light on the principles underlying anterior-posterior body axis specification and embryo patterning in ascidians and deepen our understanding of how embryogenesis is conserved among chordates.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

For this study, we have developed new tools for live cell imaging the microtubule and actin cytoskeletons and for proximity biotinylation of key cytoplasmic domains. We have collected high-quality images of the microtubule cytoskeleton in the developing ascidian embryo under various conditions in order to understand the role of microtubules in cytoplasmic reorganization.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The asymmetric distribution of cytoplasmic components is a common strategy used to establish embryo patterning. Therefore, unraveling the mechanisms that create asymmetry is critical for understanding animal development. To address this gap, we have taken an interdisciplinary approach, combining advanced microscopy applications, biophysical techniques that allow for the precise measurement and manipulation of forces, and proteomics to resolve the localization patterns of developmental determinants and the cellular and molecular mechanisms that control these patterns. This type of interdisciplinary approach has not been carried out in ascidian embryos at this stage of development and will provide an integrated understanding of the cytoskeletal-dependent mechanisms that control cytoplasmic reorganization by unraveling the dynamic interplay between cytoskeletal dynamics, force generation, and cell polarity during development. By bringing together multidisciplinary approaches and developing new tools, we are able to uniquely investigate the common strategies used to establish cytoplasmic organization in cells and embryos.

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