2 items with the tag “reactive oxygen species

  • Control of Evolvability and Chromosomal Rearrangement by Stress
    NAI 2013 University of Illinois at Urbana-Champaign Annual Report

    Gross chromosomal rearrangements (GCRs) underlie much of evolution, changing the copy number of genes, allowing development of new functions by providing redundant genetic material, reassorting protein domains and reassorting regulatory elements. Some mechanisms of chromosomal rearrangement are understood, but most are not. Using a model system in Escherichia coli, we have shown that both point mutation and GCRs occur preferentially when the cells are stressed, and require several stress-responses to be activated. We seek to understand the regulation of GCR by discovering how stress regulates the process, and what is the decision that activates the GCR pathway rather than a parallel stress-induced point mutation pathway. These are important components of the mechanisms by which organisms evolve to adapt to new or changing environments.

  • Project 7 Control of Evolvability and Chromosomal Rearrangement by Stress
    NAI 2014 University of Illinois at Urbana-Champaign Annual Report

    Evolution of the genome happens predominantly by gross chromosomal rearrangements (GCR), usually involving non-homologous recombination, and point mutation or single nucleotide variation (SNV). GCR re-assorts domains and regulatory functions, and frequently changes gene copy number, allowing further evolution. SNV changes coding sequences, modifying the properties of encoded macromolecules and their regulation. We are able to measure both SNV and GCR in the same assay in Escherichia coli, and have established that both are dramatically up-regulated in response to stress. Through many year’s work, we have learnt many details of these mechanisms, but some of the outstanding questions are crucial to understanding the significance of stress in evolution, notably the signaling and execution of the pathway from stress to mutation, and how the decision is made between SNV and GCR. This project aims to answer these questions.