PhD Defense: Make or brake it: On the roles of the cohesin acetylation cycle

PhD Defense of Marjon Suzanne van Ruiten


The human body consists of trillions of cells that all come from a single fertilized egg cell. How these cells are formed and together form an organism, is encoded in DNA molecules (the genetic material). If you were to unroll all this DNA from a cell, you would end up with a long string of about two meters. In our cells, however, these long strands are packed together so that they fit into a nucleus of only a few micrometers in diameter. The cohesin complex plays an important role in this process by making loops in the DNA. Cohesin is a molecular machine that starts with the formation of a small loop that gets enlarged over time. In this thesis we show that there appears to be a brake on this machine. Once the brake is activated, cohesin is temporarily unable to form loops. This is mediated by changing two amino acids of the cohesin complex through a process called acetylation. We also find that changing these amino acids back to their original state, via deacetylation, seems to enable cohesin to resume the formation of loops. Switching the brake on and off thus appears to be a cyclic process. When this brake is used, and which role this brake plays in cells, are important questions to be investigated in the future.

Start date and time
End date and time
Academiegebouw, Domplein 29 & online (livestream link)
PhD candidate
M.S. van Ruiten
Make or brake it: On the roles of the cohesin acetylation cycle
PhD supervisor(s)
prof. dr. R.H. Medema
prof. dr. B. Rowland