The Lyme disease agent Borrelia burgdorferi requires BB0690, a Dps homologue, to persist within ticks.
Borrelia burgdorferi survives in an enzootic cycle, and Dps proteins protect DNA against damage during starvation or oxidative stress. The role of a Dps homologue encoded by Borrelia in spirochaete survival was assessed. Dps-deficient spirochaetes were infectious in mice via needle-inoculation at the dose of 10(5) spirochaetes. Larval ticks successfully acquired Dps-deficient spirochaetes via a blood meal on mice. However, after extended periods within unfed nymphs, the Dps-deficient spirochaetes failed to be transmitted to a new host when nymphs fed. Our data suggest that Dps functions to protect the spirochaetes during dormancy in unfed ticks, and in its absence, the spirochaetes become susceptible during tick feeding. dps is differentially expressed in vivo- low in mice and high in ticks - but constitutively expressed in vitro, showing little change during growth or in response to oxidative stress. Borrelia Dps forms a dodecameric complex capable of sequestering iron. The Dps-deficient spirochaetes showed no defect in starvation and oxidative stress assays, perhaps due to the lack of iron in spirochaetes grown in vitro. Dps is critical for spirochaete persistence within ticks, and strategies to interfere with Dps could potentially reduce Borrelia populations in nature and thereby influence the incidence of Lyme disease.
Li
Xin
X
Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520-8031, USA.
Pal
Utpal
U
Ramamoorthi
Nandhini
N
Liu
Xianzhong
X
Desrosiers
Daniel C
DC
Eggers
Christian H
CH
Anderson
John F
JF
Radolf
Justin D
JD
Fikrig
Erol
E
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025065:Borrelia burgdorferi / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D018884:Ixodes / Q000254:growth & development / Q000382:microbiology*; D008193:Lyme Disease / Q000382:microbiology* / Q000635:transmission; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009758:Nymph / Q000382:microbiology; D010641:Phenotype; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014170:Transformation, Genetic
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C083911:DPS protein, Bacteria; D011994:Recombinant Proteins