Feodor Lynen Lecture:
Bacterial sRNAs, Stress Responses, and the View from Hfq
National Cancer Institute, Bethesda, Gottesms@mail.nih.gov
Bacteria such as E. coli face constant changes in their environment, availability of nutrients, and competitors. They have evolved the ability to rapidly adapt, frequently by using post-transcriptional regulators such as small non-coding RNAs (sRNAs). Studies on these sRNAs and their targets has led to a much expanded understanding of the intertwined network of regulatory interactions. In E. coli and many other bacteria, much of this sRNA-based regulation depends on the RNA chaperone Hfq, a homohexameric protein that is related to eukaryotic Sm and Lsm proteins. While in vitro tests of Hfq function have provided insight into how sRNAs and their target mRNAs bind and interact, it is clear that in vivo, the situation is significantly more complicated. Using a variety of genetic approaches, we have been dissecting Hfq function in vivo, looking at how hierarchies of sRNA function are established, how sRNAs are turned over and the effects when they are not, and the roles of Hfq beyond sRNAs. I will review how we are using mutants, global data sets from us and others, and our growing information on regulatory networks to better understand how sRNA-based regulation is working in vivo.