title: Reduced heme levels underlie the exponential growth defect of the Shewanella oneidensis hfq mutant.
abstract: The RNA chaperone Hfq fulfills important roles in small regulatory RNA (sRNA) function in many bacteria. Loss of Hfq in the dissimilatory metal reducing bacterium Shewanella oneidensis strain MR-1 results in slow exponential phase growth and a reduced terminal cell density at stationary phase. We have found that the exponential phase growth defect of the hfq mutant in LB is the result of reduced heme levels. Both heme levels and exponential phase growth of the hfq mutant can be completely restored by supplementing LB medium with 5-aminolevulinic acid (5-ALA), the first committed intermediate synthesized during heme synthesis. Increasing expression of gtrA, which encodes the enzyme that catalyzes the first step in heme biosynthesis, also restores heme levels and exponential phase growth of the hfq mutant. Taken together, our data indicate that reduced heme levels are responsible for the exponential growth defect of the S. oneidensis hfq mutant in LB medium and suggest that the S. oneidensis hfq mutant is deficient in heme production at the 5-ALA synthesis step.
authors.affiliation: Department of Biology, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Brennan
authors.affiliation: Department of Biology, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Nicholas Q
authors.initials: NQ
authors.lastname: Mazzucca
authors.affiliation: Department of Biology, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Taylor
authors.initials: T
authors.lastname: Mezoian
authors.affiliation: Department of Biology, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Taylor M
authors.initials: TM
authors.lastname: Hunt
authors.affiliation: Department of Biology, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Meaghan L
authors.initials: ML
authors.lastname: Keane
authors.affiliation: Department of Biology, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Jessica N
authors.initials: JN
authors.lastname: Leonard
authors.affiliation: Department of Chemistry and Biochemistry, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Shelby E
authors.initials: SE
authors.lastname: Scola
authors.affiliation: Department of Biology, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Emma N
authors.initials: EN
authors.lastname: Beer
authors.affiliation: Department of Biology, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Sarah
authors.initials: S
authors.lastname: Perdue
authors.affiliation: Department of Biology, Providence College, Providence, Rhode Island, United States of America.
authors.forename: Brett J
authors.initials: BJ
authors.lastname: Pellock
mesh_terms: D000622:Aminolevulinic Acid / Q000378:metabolism*; D006418:Heme / Q000096:biosynthesis* / Q000235:genetics; D035001:Host Factor 1 Protein / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D020592:Shewanella / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D035001:Host Factor 1 Protein; D006418:Heme; D000622:Aminolevulinic Acid