Topic 2: Nuclear dynamics during mitosis and ageing
When a cell divides, sister chromatids are partitioned symmetrically. In contrast, extra-chromosomal DNA circles are asymmetrically retained in one of the two daughter cells. In budding yeast, both processes rely on the proper regulation of their interaction with the nuclear pore complexes (NPCs). Chromosomes detach from NPCs during mitosis, as in mammalian cells, whereas DNA circles do not.
In our Lab, we study how yeast cells distinguish chromosomes and DNA circles from each other to ensure their proper and distinct segregations. Furthermore, we study how the retention and accumulation of DNA circles and circle-bound NPCs promotes aging of the yeast mother cell.
(Left) Chromosomes and DNA circles have different fates. In mitotic budding yeast cells, the nuclear periphery (dashed outline) and spindle pole bodies (at opposite poles of the nucleus) are labeled with GFP. The top panel shows symmetrically partitioned chromosomes, labeled with RFP, while in the bottom panel DNA circles (also RFP labeled) are retained in the mother cell nucleus where they accumulate as the cell ages.
(Right) A single cell can be trapped on an ageing chip and monitored thoughout its lifespan. The top panel shows a young cell that partitions a fluorescently labeled chromosomes symmetrically. That same cell, when aged, exhibits chromosome missegregation, with the chromosome segregated into the daughter cell (left: brightfield image, right: fluorescent image highlighting the labeled chromosome).
Contact
Deputy head of Institute of Biochemistry (IBC)
Institut für Biochemie
Otto-Stern-Weg 3
8093
Zürich
Switzerland
