Chromosome mis-segregations are not only a hallmark of most cancers and promote tumor progression; when occurring during meiosis, they also result in trisomies like Down Syndrome. The aim of our research is to understand the regulations, which ensure faithful chromosome segregation in healthy cells and which might give rise to aneuploidies when malfunctioning. We are especially interested in molecular mechanisms that control the dissolution of sister chromatid cohesion in anaphase. To this end, we are conducting cell biological studies on oocytes and early embryos of frogs and on tailored transgenic lines of human cancer cells. We are combining these in vivo-experiments with in vitro-approaches that make use of the biochemically tractable system of Xenopus egg extracts (see example below).

Cdk1-activating, stable cyclin B1 has two concentration-dependent effects in Xenopus egg extracts: While it only blocks exit from mitosis at low concentration, it additionally prevents anaphase at high concentration. (See "Projects" for details.)