Cohesin - A Two-faced Molecule

Cover of Molecular Cell journal, Volume 83, Number 17, September 7, 2023, featuring an artistic depiction of the protein complex cohesin as the Roman god Janus with two faces in profile, entwined with a colorful double helix DNA strand, on a watercolor-styled blue background, symbolizing scientific exploration of molecular biology by Cell Press
Molecular Cell Cover September 2023

The Science

Inside the microscopic cell nucleus resides our genome, a two-meter-long DNA strand meticulously organized in compact chromosomes by cohesin, a protein complex. This molecular architect facilitates DNA interactions throughout the cell cycle, shaping loops within chromosomes and mediating contacts between chromosomes.


Scientists in the lab of IMP Scientific Director Jan-Michael Peters have gained unexpected insights into the mechanisms that govern these functions: They identified a cohesin mutant which can mediate loop-extrusion in vitro and in vivo, however, it is deficient in both loop stabilization as well as sister chromatid cohesion.


Curious about the details? Check out the paper.

The Art

The cover depicts Cohesin as Janus, the two-faced ancient roman god of duality and passages, symbolizing the separation of cohesin’s two functions. Janus had a ubiquitous presence in roman mythology, his name is derived from Proto-Indo-European iehnu (“passage”) and is cognate with Sanskrit yāti (“to go, travel”).


These attributes resonate with the complex Biology of Cohesin on many layers, as it is fundamentally involved in guiding DNA compaction and thus gene expression. The key insight of this paper – the independent basis for Cohesin’s two main functions – is resembled by the dichotomy of Janus.