School of Physics Soft Condensed Matter & Biophysics Seminar Series: Presenting Narendra Maheshri, MIT

I will discuss three examples describing the utility of understanding and/or exploiting both epigenetic and genetic variability in populations of yeast cells. First, I describe an unappreciated and dominant role for cell-cycle phase on transcriptional variability and dynamics.   

 Second, I describe how variable numbers of tandemly repeated “decoy” transcription factor (TF) binding sites that bind a cognate transcriptional activator can reduce expression at the activator’s target genes, qualitatively converting the dose-response from a linear to steeper sigmoidal-like threshold response.

Third, I describe a technique we have developed for the repeated and targeted in vivo mutagenesis of multiple genes in S. cerevisiae. We show selective damage of DNA and subsequent repair by error-prone homologous recombination pathways can lead to selective >800-fold increase in mutation rate in a user-defined 20 kb target region. We discuss applications of this method for the directed evolution of multigenic phenotypes. Deployment is simple and our constructs and protocols are available to interested researchers.