Sequence and expression analysis of the ompA gene of Rickettsia peacockii, an endosymbiont of the Rocky Mountain wood tick, Dermacentor andersoni

Gerald D Baldridge, Nicole Y Burkhardt, Jason A Simser, Timothy J Kurtti, Ulrike G Munderloh
Applied and Environmental Microbiology 2004, 70 (11): 6628-36
The transmission dynamics of Rocky Mountain spotted fever in Montana appears to be regulated by Rickettsia peacockii, a tick symbiotic rickettsia that interferes with transmission of virulent Rickettsia rickettsii. To elucidate the molecular relationships between the two rickettsiae and glean information on how to possibly exploit this interference phenomenon, we studied a major rickettsial outer membrane protein gene, ompA, presumed to be involved in infection and pathogenesis of spotted fever group rickettsiae (SFGR) but which is not expressed in the symbiont. Based on PCR amplification and DNA sequence analysis of the SFGR ompA gene, we demonstrate that R. peacockii is the most closely related of all known SFGR to R. rickettsii. We show that R. peacockii, originally described as East Side agent in Dermacentor andersoni ticks from the east side of the Bitterroot Valley in Montana, is still present in that tick population as well as in D. andersoni ticks collected at two widely separated locations in Colorado. The ompA genes of R. peacockii from these locations share three identical premature stop codons and a weakened ribosome binding site consensus sequence relative to ompA of R. rickettsii. The R. peacockii ompA promoter closely resembles that of R. rickettsii and is functional based on reverse transcription-PCR results. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting showed that OmpA translation products were not detected in cultured tick cells infected with R. peacockii. Double immunolabeling studies revealed actin tail structures in tick cells infected with R. rickettsii strain Hlp#2 but not in cells infected with R. peacockii.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"