Identification of an IS-related Shiga toxin-production system in O157

Research Project

Project/Area Number	15K08484
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Bacteriology (including mycology)
Research Institution	National Agriculture and Food Research Organization
Principal Investigator	KUSUMOTO Masahiro 国立研究開発法人農業・食品産業技術総合研究機構, 動物衛生研究部門, 上級研究員 (40548210)
Project Period (FY)	2015-04-01 – 2018-03-31
Project Status	Completed (Fiscal Year 2017)
Budget Amount *help	¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000) Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000) Fiscal Year 2016: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000) Fiscal Year 2015: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Keywords	腸管出血性大腸菌 / O157 / 志賀毒素 / IS629 / EHEC / IS
Outline of Final Research Achievements	Insertion sequence (IS) elements are the simplest mobile genetic elements, and there are many copies of IS elements in the genome of enterohemorrhagic Escherichia coli (EHEC) O157. In this study, we showed that IS629, the most abundant IS elements in the O157 genome, was responsible for the production of Shiga toxin 2 (Stx2) which is the major virulence factor of EHEC. In O157, the production of Stx2 is known to be enhanced by the SOS response and following the Stx2 phage induction, but IS629 induced Stx2 and the Stx2 phage independently of SOS response. Our data suggest that IS elements promote not only bacterial genome diversification with their mobility but also toxin production in O157.