Robert Schleif
Johns Hopkins University, USA
Title: What 40-plus years of study have taught us about the DNA-looping protein AraC and its regulation of the L-arabinose operon in Escherichia coli
Biography
Biography: Robert Schleif
Abstract
The AraC protein both positively and negatively regulates expression of the L-arabinose operon in Escherichia coli. More than three hundred person-years of research spread over more than four decades has revealed much about gene regulation and transcription factors. This work included the discovery of the phenomenon of DNA looping in gene regulation, and has stimulated development of a number of techniques used in molecular biology including DNA gel retardation assays and missing contact footprinting. The talk will summarize current understanding of the mechanism by which the binding of arabinose to AraC shifts the protein from preferring to loop DNA and repressing the pBAD promoter by binding to two DNA sites separated by 210 base pairs to preferring to bind to two adjacent DNA sites and activating the promoter. Several recent experiments will be described including elucidation of the role of the N-terminal arm of the protein in controlling the protein’s DNA binding properties and experiments demonstrating that arabinose binding to one subunit affects the N-terminal arm of only the opposite subunit.