Poster abstracts
Poster number 98 submitted by Kaveendya Mallikaarachchi
Bacterial mRNA Decay Condensates are Broadly Conserved Across Bacterial Species and Play a Critical Role in Host Colonization
Kaveendya S. Mallikaarachchi (Wayne State University, Detroit, MI, USA 48202), Jason L. Huang, Shanmukha Madras, Rodrigo A. Cuellar, Zhenzhong Huang (San Francisco State University, San Francisco, CA, USA 94132), Vidhyadhar Nandana, Alisa Gega, Imalka Wanigasekara, Nadra Al-Husini (Wayne State University, Detroit, MI, USA 48202), Thomas Kim, Sean Crosson (Michigan State University, East Lansing, MI, USA 48824), Joseph C. Chen (San Francisco State University, San Francisco, CA, USA 94132), Jared M. Schrader (Wayne State University, Detroit, MI, USA 48202)
Abstract:
Bacteria typically lack membrane-bound organelles for organizing biochemical pathways. However, recent studies have revealed that they utilize biomolecular condensates as a mechanism for subcellular organization. These biomolecular condensates are phase-separated structures that organize multiple biochemical pathways without the use of a membrane. Bacterial Ribonucleoprotein Bodies (BR-Bodies) are the first biomolecular condensate discovered in bacterial cells and it compartmentalizes the bacterial RNA degradosome and substrate RNAs. In a limited number of bacteria tested so far, BR-bodies facilitate fast mRNA turnover and stress resistance, yet their phylogenetic breadth across bacteria and potential impacts on host colonization are not yet known. Here, we investigate the phylogenetic breadth of BR-bodies by recombinantly expressing RNA degradosome scaffolds from diverse bacterial species in E. coli. We observed that all RNA degradosome scaffolds tested form foci, indicating they can phase-separate into BR-bodies. This suggests that BR-bodies are likely utilized across a large majority of bacteria as a general organization mechanism. To examine the importance of BR-bodies in host colonization, we generated BR-body null mutants by truncating the C-terminal disordered region on RNase E in the plant-associated symbiont Sinorhizobium meliloti and the animal associated intracellular pathogen Brucella ovis. In both bacteria, we observed that BR-body null mutants have no detectable differences in growth in standard in vitro conditions, however both BR-body null mutants showed slower mRNA decay rates, increased stress sensitivity and marked reductions in plant or animal colonization respectively. Therefore BR-bodies that compartmentalize the mRNA decay machinery appear to be widespread across bacteria and have the capacity to overcome stress and promote host colonization, making BR-bodies a promising target for next-generation antibiotics.
Keywords: mRNA decay , BR-bodies, membrane-less organelles