Helle Ulrich (Biochemistry)
Helle Ulrich |
 |
Helle's current research focuses on the mechanisms that allow cells to cope with damage to their genes. Generally, damaged DNA cannot be copied by the cellular replication machinery, but a specialised set of DNA polymerases, dedicated to the task of reading over faulty stretches of DNA, can take over and complete the duplication of the genome even when it is damaged by radiation or environmental toxins. This process, termed DNA damage tolerance, helps a cell to survive DNA damage, but at the same time, it endangers its genomic stability, because the bypass polymerases are quite sloppy and introduce errors while copying DNA. Cells have therefore devised intricate control systems for limiting the activity of these enzymes to situations where they are beneficial, and Helle's laboratory is studying how this is accomplished.
Helle became interested in cellular responses to DNA damage at an early point in her career, during her undergraduate studies in Molecular Genetics and Biochemistry at the University of Göttingen, Germany. Her interests have always tended towards the molecular aspects of biological processes. Consequently, she took several classes in chemistry during her third year of college, which she spent as an exchange student at the University of California, Berkeley. Having passed her oral "Diplom" examinations in 1992, she went back to Berkeley to complete the thesis work for her degree and to continue with Graduate School there. Helle's doctoral work was dedicated to the mechanism and evolution of catalytic antibodies, tailor-made model enzymes that allow the investigation of questions related to catalysis but are rather remote from natural biological systems. Hence, after completion of her PhD in chemistry in 1996, she returned to "real" biology as a postdoctoral fellow, first at the University of Heidelberg and later at the Max-Planck-Institute for Biochemistry in Martinsried, Germany.
Helle chose to focus on an area of high relevance to many different aspects of cell biology: the modulation of protein function by means of ubiquitin and the ubiquitin-like modifier, SUMO. These essential factors alter the property of proteins by covalent modification. As their targets are found among virtually every cellular pathway, their study allowed her to explore a number of different topics within molecular biology, using baker's yeast as a model organism. Consequently, one of her projects inadvertently brought her back to her earlier passion for genome stability: via a small protein that had originally been identified in the course of the yeast genome sequencing project, Helle entered the pathway of DNA damage tolerance, which is - as is known today - controlled by multiple components of the ubiquitin system. Studying how ubiquitin and SUMO influence genome stability has since become the focus of her research.
In 2000, Helle established an independent group at the Max-Planck-Institute for Terrestrial Microbiology in Marburg, Germany. She was initially supported by a Habilitation fellowship from the German Research Council (DFG), but soon obtained a large 5 year-grant, the "BioFuture" award, from the German Ministry of Education and Research. In 2003, she joined the EMBO Young Investigator Programme. She started applying for academic positions during that year, and although she had an offer of a tenured professorship at a German university, she accepted a junior group leader position at the Clare Hall Laboratories of Cancer Research UK in London in 2004. The focus of this institute on DNA metabolism and genome stability and its excellent research facilities made this position more attractive to her than a university appointment. In 2006, Helle was promoted to senior group leader with a tenured position.