title: RpoS regulates essential virulence factors remaining to be identified in Borrelia burgdorferi.
abstract: BACKGROUND
  Since the RpoN-RpoS regulatory network was revealed in the Lyme disease spirochete Borrelia burgdorferi a decade ago, both upstream and downstream of the pathway have been intensively investigated. While significant progress has been made into understanding of how the network is regulated, most notably, discovering a relationship of the network with Rrp2 and BosR, only three crucial virulence factors, including outer surface protein C (OspC) and decorin-binding proteins (Dbps) A and B, are associated with the pathway. Moreover, for more than 10 years no single RpoS-controlled gene has been found to be critical for infection, raising a question about whether additional RpoS-dependent virulence factors remain to be identified.
  
  
  RESULTS
  The rpoS gene was deleted in B. burgdorferi; resulting mutants were modified to constitutively express all the known virulence factors, OspC, DbpA and DbpB. This genetic modification was unable to restore the rpoS mutant with infectivity.
  
  
  CONCLUSIONS
  The inability to restore the rpoS mutant with infectivity by simultaneously over-expressing all the three virulence factors allows us to conclude RpoS also regulates essential genes that remain to be identified in B. burgdorferi.
authors.affiliation: Department of Pathobiological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America.
authors.forename: Qilong
authors.initials: Q
authors.lastname: Xu
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Shi
authors.forename: Poonam
authors.initials: P
authors.lastname: Dadhwal
authors.forename: Fang Ting
authors.initials: FT
authors.lastname: Liang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D025065:Borrelia burgdorferi / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D020869:Gene Expression Profiling; D056426:Genetic Loci; D008193:Lyme Disease / Q000235:genetics* / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor; D037521:Virulence Factors; C069567:sigma factor KatF protein, Bacteria