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Series GSE4461

Query DataSets for GSE4461

Status

Public on Mar 15, 2006

Title

Genome-wide screen for salmonella genes required for long-term systemic infection of the mouse.

Organism

Salmonella enterica subsp. enterica serovar Typhimurium

Experiment type

Expression profiling by array

Summary

This datasets includes all arrays from the first passage through 129SvJ mice (28 days) and the second independent passage (29 days). The first passage arrays are the same as included in the experiment set "129SvJ Pass 1 28 dpi arrays" and the second passage arrays are the same as included in the experiment set "129SvJ Pass 2 28 dpi arrays". Input arrays are also included and collectively they represent two biological replicates for negative selection at ~4 weeks post infection.
Abstract: A microarray-based negative selection screen was performed to identify Salmonella enterica serovar Typhimurium (serovar Typhimurium) genes that contribute to long-term systemic infection in 129X1/SvJ (Nramp1(r)) mice. A high-complexity transposon-mutagenized library was used to infect mice intraperitoneally, and the selective disappearance of mutants was monitored after 7, 14, 21, and 28 d postinfection. One hundred and eighteen genes were identified to contribute to serovar Typhimurium infection of the spleens of mice by 28 d postinfection. The negatively selected mutants represent many known aspects of Salmonella physiology and pathogenesis, although the majority of the identified genes are of putative or unknown function. Approximately 30% of the negatively selected genes correspond to horizontally acquired regions such as those within Salmonella pathogenicity islands (SPI 1-5), prophages (Gifsy-1 and -2 and remnant), and the pSLT virulence plasmid. In addition, mutations in genes responsible for outer membrane structure and remodeling, such as LPS- and PhoP-regulated and fimbrial genes, were also selected against. Competitive index experiments demonstrated that the secreted SPI2 effectors SseK2 and SseJ as well as the SPI4 locus are attenuated relative to wild-type bacteria during systemic infection. Interestingly, several SPI1-encoded type III secretion system effectors/translocases are required by serovar Typhimurium to establish and, unexpectedly, to persist systemically, challenging the present description of Salmonella pathogenesis. Moreover, we observed a progressive selection against serovar Typhimurium mutants based upon the duration of the infection, suggesting that different classes of genes may be required at distinct stages of infection. Overall, these data indicate that Salmonella long-term systemic infection in the mouse requires a diverse repertoire of virulence factors. This diversity of genes presumably reflects the fact that bacteria sequentially encounter a variety of host environments and that Salmonella has evolved to respond to these selective forces in a way that permits both the bacteria and the host to survive.
Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc.
Keywords: Logical Set

Overall design

Computed

Contributor(s)

Chan K

Citation(s)

16518469

Submission date

Mar 13, 2006

Last update date

Mar 16, 2012

Organization

Stanford Microarray Database (SMD)