title: BB0250 of Borrelia burgdorferi is a conserved and essential inner membrane protein required for cell division.
abstract: The gene bb0250 of Borrelia burgdorferi is a homolog of the dedA family, encoding integral inner membrane proteins that are present in nearly all species of bacteria. To date, no precise function has been attributed to any dedA gene. Unlike many bacterial species, such as Escherichia coli, which has eight dedA genes, B. burgdorferi possesses only one, annotated bb0250, providing a unique opportunity to investigate the functions of the dedA family. Here, we show that bb0250 is able to restore normal growth and cell division to a temperature-sensitive E. coli mutant with simultaneous deletions of two dedA genes, yqjA and yghB, and encodes a protein that localizes to the inner membrane of E. coli. The bb0250 gene could be deleted from B. burgdorferi only after introduction of a promoterless bb0250 under the control of an inducible lac promoter, indicating that it is an essential gene in this organism. Growth of the mutant in the absence of isopropyl-β-d-thiogalactopyranoside resulted in cell death, preceded by cell division defects characterized by elongated cells and membrane bulges, demonstrating that bb0250 is required for proper cell division and envelope integrity. Finally, we show that BB0250 depletion leads to imbalanced membrane phospholipid composition in borrelia. These results demonstrate a strong conservation of function of the dedA gene family across diverse species of Gram-negative bacteria and a requirement for this protein family for normal membrane lipid composition and cell division.
authors.affiliation: Department of Pathobiological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
authors.forename: Fang Ting
authors.initials: FT
authors.lastname: Liang
authors.forename: Qilong
authors.initials: Q
authors.lastname: Xu
authors.forename: Rakesh
authors.initials: R
authors.lastname: Sikdar
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiao
authors.forename: James S
authors.initials: JS
authors.lastname: Cox
authors.forename: William T
authors.initials: WT
authors.lastname: Doerrler
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D025065:Borrelia burgdorferi / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D016923:Cell Death; D002455:Cell Division; D002462:Cell Membrane / Q000737:chemistry; D017124:Conserved Sequence; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D020043:Genes, Essential; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000032:analysis; D011401:Promoter Regions, Genetic; D015533:Transcriptional Activation
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D010743:Phospholipids; C530999:YghB protein, E coli; C531000:YqjA protein, E coli