Studying the complexities of transcriptional regulation

The process of gene expression is central to the modern understanding of how cellular systems function. In this process, a special kind of regulatory proteins, called transcription factors, are important to determine how much protein is produced from a given gene. As biological information is transmitted from transcription factor concentration to mRNA levels to amounts of protein, various sources of noise arise and pose limits to the fidelity of intracellular signaling. This thesis concerns itself with several aspects of stochastic gene expression: (i) the mathematical description of complex promoters responsible for the stochastic production of biomolecules, (ii) fundamental limits to information processing the cell faces due to the interference from multiple fluctuating signals, (iii) how the presence of gene expression noise influences the evolution of regulatory sequences, (iv) and tools for the experimental study of origins and consequences of cell-cell heterogeneity, including an application to bacterial stress response systems.