Project (Peter Lénárt)




Evolution of oocyte meiosis

Our research group is interested in the specialized meiotic divisions of oocytes producing the fertilizable egg. We want to understand how conserved molecular machines, which for example build cytoskeletal structures or drive the cell cycle, adapt to meiosis specific functions. How cytoskeletal filaments mediate division of the exceptionally large oocyte with a volume two orders of magnitude larger than somatic cells? What is the mechanism of the highly asymmetric divisions that produce a single large egg cell? How is cell cycle regulation altered to skip S-phase between the two meiotic divisions producing a haploid egg?
We use starfish oocytes as a model system, because they are particularly well suited to study meiosis using cell biological and live-cell imaging assays. These oocytes are also available in large amounts and proceed through meiosis very synchronously, which recently allowed us to record a phospho-proteomics ‘time course’ of the entire meiosis.
We are currently looking for a PhD candidate interested in analyzing these proteomics data, as well as proteomics and transcriptomics data from oocytes of other animal species. Our goal is to identify the conserved ‘molecular core’ of meiotic regulation. Specifically, it is known that in all deuterostome species investigated so far (including vertebrates and the echinoderm starfish) the kinase Mos is specifically and exclusively expressed in meiosis. Inhibition of Mos results in the loss of many meiosis specific features of division, for example, S-phase will take place between the two meiotic divisions, and divisions will be symmetric. We want to identify conserved molecular modules controlled by Mos, and more generally those mediating meiosis specific functions. Potential candidates will be analyzed bioinformatically looking for molecular and functional conservation across animal species. Derived hypotheses will be tested experimentally in starfish oocytes using molecular perturbations combined with cell biological and imaging assays.



Homepage Research Group

https://www.mpibpc.mpg.de/16329993/lenart



For more information see for instance:

  • Wesolowska N, Avilov I, Machado P, Geiss C, Kondo H, Mori M, Lénárt P.
    Actin assembly ruptures the nuclear envelope by prying the lamina away from nuclear pores and nuclear membranes in starfish oocytes.
    Elife. 2020 Jan 28;9. pii: e49774.

  • Burdyniuk M, Callegari A, Mori M, Nedelec F, Lénárt P
    F-Actin nucleated on chromosomes coordinates their capture by microtubules in oocyte meiosis.
    J Cell Biol. 2018 Aug 6;217(8):2661-2674.

  • Bischof J, Brand CA, Somogyi K, Májer I, Thome S, Mori M, Schwarz US, Lénárt P.
    A cdk1 gradient guides surface contraction waves in oocytes.
    Nat Commun. 2017 Oct 11;8(1):849.