Cellular Noise Regulons and the Quantitative Dynamics of the Environmental Stress Response in Yeast
Speaker: Hana El-Samad, Grace Boyer Jr. Faculty Endowed Chair Department of Biochemistry and Biophysics California Institute for Quantitative Biosciences University of California, San Francisco
Series: Other Events
Location: J223 Equad
Date/Time: Thursday, November 29, 2012, 3:30 p.m. - 4:30 p.m.
Stochasticity is a hallmark of cellular processes, and different classes of genes show large differences in their cell-to-cell variability (noise). To decipher the sources and consequences of this noise, we systematically measured pairwise correlations between large numbers of genes, including those with high variability. We find that there is substantial pathway variability shared across similarly regulated genes. This induces quantitative correlations in the expression of functionally related genes such as those involved in the Msn2/4 stress response pathway, amino acid biosynthesis, and mitochondrial maintenance. Our results argue that a limited number of well-delineated noise regulons operate across a yeast cell and that such coordinated fluctuations enable a stochastic but coherent induction of functionally related genes. We show that pathway noise is a quantitative tool for exploring pathway features and regulatory relationships in un-stimulated systems. These fluctuation-based investigations reveal many system level properties, which we explore mechanistically for PKA signaling.
Hana El-Samad is a faculty member in the department of Biochemistry and Biophysics at the University of California, San Francisco and the California Institute for Quantitative Biosciences (QB3), where she holds the Grace Boyer Junior Endowed Chair in Biophysics and is the deputy director of the UCSF Systems and Synthetic Biology Center. She is a 2009 Packard Fellow, a recipient of the 2011 Donald P. Eckman Award and the 2012 CSB2 prize in Systems Biology. Dr. El-Samad joined UCSF after obtaining a doctorate degree in Mechanical Engineering from the University of California, Santa Barbara, preceded by a Masters Degree in Electrical Engineering from the Iowa State University. Dr. El-Samad's research group emphasizes the role of control theory and dynamical systems in the study of biological networks. Her research interests include the investigation of stress responses and biological stochastic phenomena, in addition to the establishment of computational and technological infrastructures that allow for their quantitative probing in single cells.