Open Accessmkp-1 Encoding Mitogen-Activated Protein Kinase Phosphatase 1, a Verotoxin 1 Responsive Gene, Detected by Differential Display Reverse Transcription-PCR in Caco-2 Cells
Author(s) -
Shihoko Kojima,
Itaru Yanagihara,
Gengo Kono,
Tomomi Sugahara,
Hatsumi Nasu,
Mika Kijima,
Akiko Hattori,
Takao Kodama,
Ken Ichi Nagayama,
Takeshi Honda
Publication year - 2000
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.68.5.2791-2796.2000
Subject(s) - biology , anisomycin , microbiology and biotechnology , cycloheximide , differential display , protein kinase a , junb , gene expression , protein subunit , protein biosynthesis , northern blot , gene , kinase , biochemistry
The major cytotoxic effect of the verotoxins (VTs) produced by strains of VT-producingEscherichia coli is the inhibition of host-cell protein synthesis, but VTs are also suspected to play a role in apoptotic cell signaling and cytokine release. Four differentially expressed genes, includingmkp-1 (encoding mitogen-activated protein kinase phospatase 1), were detected by differential display reverse transcription-PCR (DD RT-PCR) stimulated by VT1 in Caco-2 cells. Northern blot analysis showed the induction ofmkp-1 mRNA 6 h after VT1 stimulation. Neither mutant VT1 (mutVT1), harboring two mutations in the A subunit (E167Q-R170L), nor cycloheximide inducedmkp-1 mRNA, butmkp-1 mRNA was detected with both wild-type VT1 (wtVT1) and anisomycin, a 28S rRNA inhibitor. Therefore, we concluded that the A subunit of VT1 was essential formkp-1 induction. Increased amounts of phosphorylated c-Jun protein were also found with wtVT1 and anisomycin. Although the precise mechanism of induction of MKP-1 is unknown, we hypothesized that 28S rRNA not only was a sensor for ribotoxic stress, but also was involved in the signal cascade of MKP-1. This is the first report of detection by DD RT-PCR of cellular genes induced by bacterial toxins.