Peter Lenart


I have just moved to the Max-Planck Institute for Biophysical Chemistry in Göttingen, Germany where I will set up a research group and coordinate the Live-cell Imaging Facility. Before, I was staff scientist (2008) and then group leader (2011) at the European Molecular Biology Laboratory (EMBL), Heidelberg Germany. Previously I spent three years as postdoctoral fellow in the laboratory of Jan-Michael Peters at the Research Institute of Molecular Pathology (IMP), Vienna, Austria, preceded by doctoral work with Jan Ellenberg at EMBL, Heidelberg. I am originally from Budapest, Hungary where I studied biology at the Eötvös Loránd University.

I have always been fascinated by the internal dynamics of cells, cell division in particular, and by having the possibility to visualize this dynamics directly in the live cells by light microscopy. I first started by looking at fertilization in plants, and spent significant time looking at mitosis in cultured mammalian cells, but then finally settled on studying meiosis in starfish oocytes. This somewhat exotic model system is exceptionally suited for live imaging, and thereby it allowed us over the past years to reveal key mechanisms underlying these specialized divisions producing the fertilizable egg.

 

The same, only different: How does the cell division machinery adapt to divide the large oocyte?


We study the specialized oocyte divisions that produce the fertilizable egg. Our general aim is to understand how the cell division machinery adapted to this specialized function, dividing the very large oocyte in a very asymmetric manner to retain all nutrients stored for the embryo in a single large egg. We will demonstrate the underlying principles through a couple examples for such adaptations to meiosis-specific functions.

Recently we revealed a novel, actin-driven mechanism required to break the exceptionally large oocyte nucleus. This involves the assembly of a massive but very transient actin ‘shell’ under the nuclear envelope mediated by the Arp2/3 nucleator complex. We could show that the actin shell forces apart the nuclear membranes and the underlying lamina, and thereby leading to destabilization of the nuclear envelope.

As another example, we showed how the capture of chromosomes scattered in the very large oocyte nucleus is coordinated in order to incorporate each and every one of them into the forming meiotic spindle. Surprisingly, this is again mediated by the actin cytoskeleton, which transports chromosomes near to microtubules and at the same time coordinates the timing of their capture.