Visualisation of Secreted Translocator and Effector Proteins during EPEC and EHEC 0157:H7 Type III Secretion

Enteropathogenic (EPEC) and enterohaemorrhagic E.coli (EHEC) employ a type III secretion system (TTSS) to translocate effector proteins into host intestinal cells. Electron microscopy combined with in situ immunogold labelling will be used to examine the structure of the EPEC:EHEC TTSS, its assembly and the secretion of effector proteins. Type III secreted proteins will be put under control of the tight arabinose promoter in order to study the kinetics of assembly and regulation of secretion.
A recently developed red blood cell (RBC) model of infection combined with in situ gold labelling will be employed to examine cell contact-dependent type III secretion and formation of the host cell membrane translocation pore. <P>The proposed studies should lead to a more detailed understanding of the structure and assembly of the EPEC:EHEC TTSS.