title: Multicopy Single-Stranded DNA Directs Intestinal Colonization of Enteric Pathogens.
abstract: Multicopy single-stranded DNAs (msDNAs) are hybrid RNA-DNA molecules encoded on retroelements called retrons and produced by the action of retron reverse transcriptases. Retrons are widespread in bacteria but the natural function of msDNA has remained elusive despite 30 years of study. The major roadblock to elucidation of the function of these unique molecules has been the lack of any identifiable phenotypes for mutants unable to make msDNA. We report that msDNA of the zoonotic pathogen Salmonella Typhimurium is necessary for colonization of the intestine. Similarly, we observed a defect in intestinal persistence in an enteropathogenic E. coli mutant lacking its retron reverse transcriptase. Under anaerobic conditions in the absence of msDNA, proteins of central anaerobic metabolism needed for Salmonella colonization of the intestine are dysregulated. We show that the msDNA-deficient mutant can utilize nitrate, but not other alternate electron acceptors in anaerobic conditions. Consistent with the availability of nitrate in the inflamed gut, a neutrophilic inflammatory response partially rescued the ability of a mutant lacking msDNA to colonize the intestine. These findings together indicate that the mechanistic basis of msDNA function during Salmonella colonization of the intestine is proper production of proteins needed for anaerobic metabolism. We further conclude that a natural function of msDNA is to regulate protein abundance, the first attributable function for any msDNA. Our data provide novel insight into the function of this mysterious molecule that likely represents a new class of regulatory molecules.
authors.affiliation: Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas, United States of America; Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America.
authors.forename: Johanna R
authors.initials: JR
authors.lastname: Elfenbein
authors.affiliation: Paul G. Allen School of Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America.
authors.forename: Leigh A
authors.initials: LA
authors.lastname: Knodler
authors.affiliation: Integrative Omics Group, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America.
authors.forename: Ernesto S
authors.initials: ES
authors.lastname: Nakayasu
authors.affiliation: Integrative Omics Group, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America.
authors.forename: Charles
authors.initials: C
authors.lastname: Ansong
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, United States of America.
authors.forename: Heather M
authors.initials: HM
authors.lastname: Brewer
authors.affiliation: Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas, United States of America.
authors.forename: Lydia
authors.initials: L
authors.lastname: Bogomolnaya
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, Texas, United States of America.
authors.forename: L Garry
authors.initials: LG
authors.lastname: Adams
authors.affiliation: Department of Pathology and Laboratory Medicine, School of Medicine, University of California-Irvine, Irvine, California, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: McClelland
authors.affiliation: Integrative Omics Group, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America.
authors.forename: Joshua N
authors.initials: JN
authors.lastname: Adkins
authors.affiliation: Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas, United States of America.
authors.forename: Helene L
authors.initials: HL
authors.lastname: Andrews-Polymenis
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D004277:DNA, Single-Stranded / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development; D007422:Intestines / Q000382:microbiology*; D051379:Mice; D012486:Salmonella typhimurium / Q000235:genetics / Q000254:growth & development
chemical_list: D004277:DNA, Single-Stranded