Open AccessCoxiella burnetii type IVB secretion system region I genes are expressed early during the infection of host cells
Author(s) -
Morgan John K.,
Luedtke Brandon E.,
Thompson Herbert A.,
Shaw Edward I.
Publication year - 2010
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2010.02072.x
Subject(s) - coxiella burnetii , biology , gene , orfs , q fever , gene expression , rickettsiaceae , virology , legionella pneumophila , genetics , open reading frame , microbiology and biotechnology , rickettsiales , bacteria , peptide sequence
Analysis of the Coxiella burnetii RSA 493 (Nine Mile phase I strain) genome revealed ORFs with significant homology to the type IVB secretion system (T4BSS) of Legionella pneumophila . The T4BSS genes exist primarily at two loci, designated regions I (RI) and II. In C. burnetii , little is known about the T4BSS regions and the role they play in establishing and/or maintaining infection. Coxiella burnetii T4BSS RI contains genes arranged in three linkage groups: (1) icmW →CBU1651→ icmX , (2) icmV → dotA →CBU1647, and (3) icmT → icmS → dotD → dotC → dotB →CBU1646. We used reverse transcriptase (RT)‐PCR to demonstrate transcriptional linkage within the groups, and that icmX , icmV , and icmT are transcribed de novo by 8 h post infection (hpi). We then examined the transcript levels for icmX , icmW, icmV , dotA, dotB , and icmT during the first 24 h of an infection using quantitative RT‐PCR. The expression initially increased for each gene, followed by a decrease at 24 hpi. Subsequently, we analyzed IcmT protein levels during infection and determined that the expression increases significantly from 8 to 24 hpi and then remains relatively constant. These data demonstrate temporal changes in the RNA of several C. burnetii T4SS RI homologs and the IcmT protein. These changes correspond to early stages of the C. burnetii infectious cycle.