A mutation inactivating the methyltransferase gene in avirulent Madrid E strain of Rickettsia prowazekii reverted to wild type in the virulent revertant strain Evir.
Rickettsia prowazekii Madrid E (E) strain is an effective vaccine, but can revert to virulent status when passaged in animals. The aim of this study is to identify the reverse mutation that may determine the virulence of R. prowazekii by comparing the genetic structures of E strain and its virulent revertant Evir strain. We determined that the gene (Rp028/Rp027) encoding the methyltransferase was mutated by frameshift in avirulent E strain but not in virulent revertant Evir strain and wild type virulent Breinl strain. We conclude that the mutation in the E strain gene reverts to wild type in the virulent revertant Evir strain. Whether the mutation plays an essential role in the attenuation of E strain needs to be further investigated.
Zhang
Jian-Zhi
JZ
Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609, USA.
Hao
Jun-Fang
JF
Walker
David H
DH
Yu
Xue-Jie
XJ
D001483:Base Sequence; D008780:Methyltransferases / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D016366:Open Reading Frames; D012283:Rickettsia prowazekii / Q000235:genetics* / Q000472:pathogenicity*; D012436:S-Adenosylmethionine / Q000502:physiology; D014158:Transcription, Genetic; D014774:Virulence
D012436:S-Adenosylmethionine; D008780:Methyltransferases