Improved Expression Systems for Regulated Expression in Salmonella Infecting Eukaryotic Cells

摘要: In this work we describe a series of improvements to the Salmonella-based salicylate-inducible cascade expression system comprised plasmid-borne module, where target gene is driven by Pm promoter governed XylS2 regulator, and genome-integrated regulatory module controlled nahR/Psal system. We have constructed set high low-copy number plasmids bearing modified versions with more versatile multiple cloning site different combinations following elements: (i) nasF transcriptional attenuator, which reduces basal levels, (ii) strong ribosome binding site, (iii) Type III Secretion System (TTSS) signal peptide from effector protein SspH2 deliver proteins directly eukaryotic cytosol bacterial infection animal cells. show that can be used direct broad range production levels. Furthermore, demonstrate efficient reduction attenuator allows genes encoding highly cytotoxic such as colicin E3 even in absence its immunity protein. Additionally, Salmonella TTSS able translocate most produced cytoplasm infected HeLa Our results indicate these vectors represent useful tools for regulated overproduction heterologous culture or cells, toxic pathogenesis studies.