Institut Jacques Monod seminar – Jens Januschke

Invited by the Guichet lab, Jens Januschke ( Faculty of Life at the University of Dundee, Scotland, UK) will present an Institut Jacques Monod on the theme:

When size determines fate: rethinking asymmetric stem cell division of neural stem cells of the fly

Abstract:

How does a stem cell produce two daughters with different identities? Classical models emphasise that in intrinsically controlled asymmetric cell division, unequal inheritance of molecules can determine fate, ensuring for instance in some systems that one daughter retains stem cell identity while the other embarks on differentiation. But what if something as simple as cell size could override these molecular instructions?

Asymmetric cell division is a fundamental mechanism of development and tissue homeostasis. In Drosophila neural stem cells, this process generates daughters that differ in fate but also dramatically in size. Understanding how this physical asymmetry emerges reveals an intricate interplay between cell polarity, cortical mechanics and membrane dynamics. Spatially controlled actomyosin contractility and local membrane expansion work together to shape dividing cells, translating molecular organisation into differences in daughter-cell size.

Intriguingly, cell size is more than a passive consequence of asymmetric division. It can actively influence developmental decisions, even challenging the instructions provided by inherited fate determinants. This raises the possibility that a cell’s physical characteristics are integral to how its identity is established and maintained.

In this seminar I will summarise our findings and sketch our direction of travel on the regulation of cell size asymmetry and its contribution on cell fate.

Jens Januschke is joint Head of Molecular, Cell & Developmental Biology in the Faculty of Life at the University of Dundee. He studied at the University of Cologne and obtained his PhD in genetics from the University of Paris VI before joining the Institute for Research in Biomedicine in Barcelona as a postdoc. Jens started his independent research at the University of Dundee for which he was awarded a Sir Henry Dale fellowship in 2013. In 2023 Jens was awarded a personal chair in Developmental Cell Biology at the University of Dundee.

His group is interested in fundamental aspects of cell function during development. He uses Drosophila as a model system with a focus on epithelial biology and epithelial derived asymmetrically dividing neural stem cells of the developing central nervous system. His group uses genetics, chemical genetics and live cell imaging to unravel principles of how the cell polarity machinery controls epithelial mechanics as well as cell fate decisions in the developing nervous system.