Emeritus Prof Ian Dawes
Response of eukaryotic organisms to oxidative stress and ageing. He was a pioneer in the field of yeast responses to oxidative stress demonstrating that yeast cells have inducible responses to peroxides, free-radicals and lipid peroxides and showing the cellular role of glutathione using mutants affected in glutathione metabolism. His group also showed cells arrest in the cell cycle in response to oxidant damage; in G2 in response to H2O2, and in G1 in response to superoxide anion or lipid hydroperoxides. They identified the entire set of yeast genes involved in responses of cells to five different oxidants, providing an extremely detailed view of how particular cell systems function in the cellular defense, repair and survival mechanisms. Genes involved in signalling oxidative damage to cell cycle control have been identified, together with those involved in adaptive responses to reactive oxygen species. In collaboration with Prof Breitenbach he has shown cell ageing in yeast is affected by oxidative stress, and aged cells undergo a program of programmed cell death.
Molecular analysis of control of one-carbon and folate metabolism in yeast. Prof Dawes has also made a major contribution to understanding how cells control one-carbon metabolism in yeast. This elucidated the molecular basis of how 1-C metabolism is regulated, how cells control the flow of metabolites from the major 1-C donors (serine, glycine and formate) to the products and how the metabolic steps are modulated between the cytoplasm and the mitochondrion. This integrated the role of different controls at the level of gene expression as well as enzyme activity.
Molecular mechanisms involved in initiation and timing of cell development. He showed for sporulation in Bacillus subtilis and Saccharomyces cerevisiae that: cell development can only be initiated at a particular stage in the cell cycle; development can only be initiated in cells that have attained a particular size; and that genes are expressed in a sequential way during meiotic development. He determined molecular mechanisms controlling sequential gene expression by cloning and characterising promoters and analysing regulation of several sporulation-specific genes. This identified a control motif in meiotically activated genes which is responsible for one of the main switching events during meiotic development.