Characterization of the human NoCut pathway

• Applicant: Dr. Patrick Steigemann
• Subject Area: Cell Biology
• Term: from 2006 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 36514477

Failures in Mitosis can lead to aneuploidy and genomic instability, a hallmark of most solid tumours. Therefore, mitosis is controlled by checkpoints that delay its progression for error correction. Experimental evidence indicates that in human cells segregation failures like lagging or bridged anaphase chromosomes cause a delay in subsequent cytokinesis, suggesting a late mitotic checkpoint monitoring completion of segregation. The underlying molecular pathway is not known, but might be related to a recently discovered pathway in yeast, termed NoCut, which temporally coordinates segregation with completion of cytokinesis. This project aims to elucidate the putative human NoCut pathway by live cell microscopy and inactivation of candidate molecules. First, time-resolved single cell assays using fluorescently tagged proteins will be developed to detect lagging and bridged chromosomes, to determine the timing of cytokinesis and to probe for DNA double strand breaks in vivo. This will allow to determine under which conditions segregation errors delay cytokinesis in human cells. The function of human orthologues of yeast NoCut genes will then be tested by their depletion using RNAi or inhibition with small molecules. Identification of the molecules constituting this pathway in human cells will thus shed light on an uncharacterized cell biological process contributing to genomic stability, which in the long run might provide potential new targets for improved cytostatic tumour therapy.

• DFG Programme: Research Fellowships
• International Connection: Switzerland
• Host: Dr. Daniel Gerlich