Christian Häring

I first learned about the opportunities at the IMP while working on my undergraduate diploma thesis in Tom Cech’s lab at the University of Colorado at Boulder. Tom had invited Kim Nasmyth, who was touring the Rocky Mountains for one of his favourite hobbies - climbing - to stop by and give a talk in Boulder.

Kim presented the work of a postdoc in his group, Frank Uhlmann, who had just discovered that proteolytic cleavage of one subunit of the then only recently discovered cohesin complex by an enzyme named separin (separase) is the long sought after trigger for the sudden splitting of sister chromatids during mitosis. This story was so fascinating that I knew I wanted to work on chromosome segregation next. I therefore applied to the Vienna PhD Programme and was fortunate enough to get an offer to join Kim’s group in May 2000.

The next 4½ years at IMP were amongst the most exciting times of my life, definitely scientifically but also privately. In the lab I was trying to work out how the four cohesin subunits could cooperate in holding sister DNAs together. I was building on Andreas Hochwagen’s work of co-expressing fragments of the subunits in insect cells to study their interactions. Kim, like every full-hearted geneticist, was initially somewhat sceptical of using massively overproduced pieces of recombinant proteins to find out how they could function.

But as the puzzle pieces started to come together and more and more data suggested that the complex forms an annular architecture, the cohesin ring model took off. In the following year Stephan Gruber and I could obtain further evidence for chromosome entrapment by cohesin rings in vivo, and we started to gain confidence in our model. The ring idea of course raised many follow-on questions, and I spent the rest of my PhD and another year as bridging postdoc trying to work out the molecular machinery behind cohesin rings using biochemical and structural biological approaches in collaboration with Jan Löwe at the LMB in Cambridge and many other members of Kim’s group.

But it was not only my own research topic that I found so fascinating at the IMP. The familial spirit at the institute, the outstanding scientists, and Vienna as one of the most vibrant cities in Europe provided such a fantastic and dynamic environment that I never wanted to leave. There was always something special going on, be it the glamorous IMP Conferences at the Imperial Hofburg, the wild beer sessions on the rooftop terrace, the homicidal sledge rides at the ski trips to Carinthia or Salzburg, or the Group Leader cancan dance at the Christmas party. But eventually I needed to move on, and while searching for postdoc positions Kim offered me to join him in setting up his new lab at the Biochemistry Department at the University of Oxford.

This sounded like a great opportunity, would it not only allow me to complete my work and proof once and for all the cohesin ring model even to the most sceptical colleagues in the field, but also give me an opportunity to practice how it would be organizing a research group without risking much except Kim’s patience and research budget. In the beginning of 2005 Vito Katis and I formed the vanguard that set up the Nasmyth lab in Oxford.

This established traditional institution was truly quite different to the IMP, and it took me not long to realize how unique the IMP actually was. With much support from the technicians and students who joined us, we managed to set up a functional lab before the rest of the group arrived from Vienna. As much as I missed Austria, England had also many fascinating aspects, like cheering for Kim’s PhD student Andrea Pauli rowing in the Oxford Blues Boat at Henley-on-Thames, chasing those invading North American squirrels in the backyard, or competing with the PI at cricket or a very British (e.g. wet) round of golf.

In late 2007, I moved to EMBL Heidelberg to start my own group. At EMBL I found many of the highlights I remembered from the IMP, like a young and energetic atmosphere, outstanding scientists at every level, excellent research support, and the freedom to try out ideas that first seemed a bit crazy (and probably still are). I am privileged to work together with a small team of outstanding PhD students, postdocs, and technicians.

Together we are trying to decipher the mechanics behind the dramatic structural changes chromosomes undergo in preparation for cell division using a highly interdisciplinary approach that combines cell, structural, and chemical biology with biochemistry and yeast genetics. The decision for our research topic was very much influenced from some of the pioneering discoveries made in Jan-Michael Peters’ group at the IMP. We also keep close ties with Vienna, including an active collaboration with Karl Mechtler and his team. I therefore believe that the IMP is still a very important part of my (scientific) life, which I hope it will continue to be in the future.

By Christian Häring, first published in 2011