In the Svenningsen group, we combine techniques from molecular biology, genetics, growth physiology and mathematical modelling to address fundamental questions in gene regulation, especially concerning RNA-centered regulatory mechanisms. We strive to always put the study of detailed molecular mechanisms into the context of the behavior of the bacterial population as a whole.
Dynamic regulation of the tRNA pool
Transfer RNAs (tRNA) are the most numerous noncoding RNAs found in the cell, and serve a key role in protein synthesis. Using an improved method of quantification, we have recently demonstrated highly dynamic regulation of tRNA levels in the model bacterium Escherichia coli. It turns out that this bacterium is continually adjusting the levels of available tRNA to match the current demand for tRNA in protein synthesis, by breaking down excess tRNA. Our focus is now on understanding how this demand-based regulation of tRNA levels occur, and how it helps bacteria cope with poor growth conditions.
Quorum sensing control of phage-bacterial interactions
Bacteria have developed a multitude of mechanisms to protect themselves from attack by phages. We find that E. coli upregulates an anti-phage defense mechanism when growing in crowded environments, as indicated by the presence of quorum-sensing signaling molecules produced by surrounding bacteria. A more sophisticated example of this strategy was found in the fish pathogen Vibrio anguillarum, which chooses between different anti-phage defense mechanisms dependent on quorum-sensing signals. We are currently focused on a marine prophage that appears to eavesdrop on the host cell’s quorum sensing system to goven its decision to induce lytic development. We are also interested in how the spatial structures that are developed as bacteria grow (e.g., microcolonies, biofilm) impact phage-bacterial interactions, and have recently shown that microcolonies can sustain growth while undergoing attack by a lytic phage, because the growth of bacteria throughout the spherical colony exceeds the killing by phage on the surface.