Events and seminars

This year's Murray Lecture will be given by Professor Kim Naysmith, who completed his doctoral studies in the Department of Molecular Biology in the late 1970s with Murdoch Mitchison. This is held annually in honour of Noreen and Ken Murray. Sir Ken Murray developed the vaccine against Hepatitis B and was one of the founders of Biogen. He was also the founder and Chairman of the Darwin Trust of Edinburgh, a charity that still supports many young, international biologists in their PhD studies both here in Edinburgh and elsewhere in the UK.

Previous Murray Lecture speakers include: Prof. Sydney Brenner (inaugural - 2014), Sir Paul Nurse (2015), Prof. Randy Schekman (2016), Prof Adrian Krainer (2017), Prof Linda Partridge (2018), Prof. Joan Steitz (2019), Prof. Bonnie Bassler (2022), Prof. Phil Sharp (2023) and Prof. Sir Steve Jackson (2024).https://www.bioch.ox.ac.uk/research/nasmythTitle:

How are sister DNAs held together?

Summary:

In eukaryotic cells, sister DNAs are held together from their creation during DNA replication until their disjunction during anaphase. This phenomenon, known as sister chromatid cohesion, is essential for the stable attachment of sister kinetochores to spindles emanating from opposite poles of the cell and hence for their eventual disjunction to opposite poles when cohesion is eventually destroyed. Cohesion is mediated by a multi-subunit complex called cohesin whose Smc1, Smc3, and Scc1 (kleisin) subunits associate in a pairwise manner to form a huge ring. I proposed nearly a quarter of century ago that sister DNAs are held together not by a proteinaceous glue but instead by a topological mechanism, namely co-entrapment within the cohesin ring, which is opened at the onset of anaphase due to cleavage of Scc1 by the protease Separase.  My talk will discuss the evidence for this hypothesis, how DNAs are entrapped by cohesin rings during DNA replication, and how this state is maintained in post-replicative cells. Cohesin also organizes the morphology of interphase chromosomes and is thought to do so through an ability to rapidly extrude vast loops of DNA, an activity that is particularly important during meiosis, for facilitating the interaction of enhancers with their cognate promoters, and for making possible the complex recombination events that produce the huge diversity of antibodies and T cell receptors. Loop extrusion appears to be common to all complexes containing Smc proteins, both eukaryotic and prokaryotic, but the mechanism of remains poorly understood and a key issue remains whether or not DNA loops are extruded through Smc-kleisin rings.  

Biosketch:

After retiring from the Whitely chair (2006-2023), Kim Nasmyth is currently working as a postdoc in the Department of Biochemistry, University of Oxford. He was a PhD student in Mitchison’s lab in Edinburgh (1974-77), a post doc in Seattle Washington (1978-1980), a Robertson research fellow at Cold Spring Harbor (1980-81), and a member of staff at the MRC laboratory for molecular biology in Cambridge (1982-87) before moving to Research Institute of Molecular Pathology (I.M.P) in Vienna, where he was a senior scientist from 1988 to 1997 and director from 1997 to 2006. His scientific work has addressed the mechanisms by which genes are turned on and off during development, how DNA replication is controlled, and how chromosomes are segregated during mitosis and meiosis. It has been recognized by several awards, including the Gairdner foundation prize, the Boveri award for Molecular Cancer Genetics, the Croonian lecture of the Royal society, the Austrian Wittgenstein prize, the Louis Jeantet prize for Medicine, the Unilever Science prize, the Breakthrough prize, the Biochemistry Centenary award, and the FEBS Silver Medal. He is a fellow of the Royal Society, a member of the Austrian Academy of Sciences, a foreign honorary member of the American Academy of Arts and Sciences, and a member of the USA National Academy of Sciences.