Open AccessNew Tick Defensin Isoform and Antimicrobial Gene Expression in Response to Rickettsia montanensis Challenge
Author(s) -
Shane M. Ceraul,
Sheila M. Dreher-Lesnick,
Joseph J. Gillespie,
M. Sayeedur Rahman,
Abdu F. Azad
Publication year - 2007
Publication title -
infection and immunity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.508
H-Index - 220
eISSN - 1070-6313
pISSN - 0019-9567
DOI - 10.1128/iai.01815-06
Subject(s) - biology , defensin , rocky mountain spotted fever , dermacentor variabilis , rickettsia , spotted fever , antimicrobial , microbiology and biotechnology , tick , gene , rickettsia rickettsii , beta defensin , antimicrobial peptides , virology , genetics , ixodidae , virus
Recent studies aimed at elucidating the rickettsia-tick interaction have discovered that the spotted fever group rickettsiaRickettsia montanensis , a relative ofR. rickettsii , the etiologic agent of Rocky Mountain spotted fever, induces differential gene expression patterns in the ovaries of the hard tickDermacentor variabilis . Here we describe a new defensin isoform, defensin-2, and the expression patterns of genes for three antimicrobials, defensin-1 (vsnA1 ), defensin-2, and lysozyme, in the midguts and fat bodies ofD. variabilis ticks that were challenged withR. montanensis . Bioinformatic and phylogenetic analyses of the primary structure of defensin-2 support its role as an antimicrobial. The tissue distributions of the three antimicrobials, especially the twoD. variabilis defensin isoforms, are markedly different, illustrating the immunocompetence of the many tissues thatR. montanensis presumably invades once acquired by the tick. Antimicrobial gene expression patterns inR. montanensis -challenged ticks suggest that antimicrobial genes play a role during the acquisition-invasion stages in the tick.