CsrA
Related genes: csrA;
Keywords: Regulation;
Characteristics:
 Belongs to a highly conserved family of global regulators that typically control stationary phase traits post-transcriptionally
Functions:
Post-transcriptional repression of the transmission regulon
Mechanism:
Binds to particular mRNAs at a consensus sequence encompassing the ribosome binding site (RBS), destablizing the mRNAs and preventing their translation
References:
 Molofsky AB, Swanson MS, 2003. Legionella pneumophila CsrA is a pivotal repressor of transmission traits and activator of replication. Mol. Microbiol. 50(2):445-461.
Molofsky AB, Swanson MS, 2004. Differentiate to thrive: lessons from the Legionella pneumophila life cycle. Mol. Microbiol. 53(1):29-40.
LetA/S
Related genes: letA;
letS;
Keywords: Regulation;
Two-component system;
Functions:
Activates gene expression indirectly by counteracting the repressor of translation known as CsrA or RsmA
Mechanism:
Predicted to induce the expression of a crsB regulatory RNA that alleviates CsrA binding to mRNAs
References:
Hammer BK, et al., 2002. A two-component regulator induces the transmission phenotype of stationary-phase Legionella pneumophila. Mol. Microbiol. 44(1):107-118.
Bachman MA, Swanson MS, 2004. The LetE protein enhances expression of multiple LetA/LetS-dependent transmission traits by Legionella pneumophila. Infect. Immun. 72(6):3284-3293.
Molofsky AB, Swanson MS, 2004. Differentiate to thrive: lessons from the Legionella pneumophila life cycle. Mol. Microbiol. 53(1):29-40.
RelA
Related genes: relA;
Keywords: Regulation;
Enzyme;
Functions:
Dispensable for intracellular growth within amoebae or the alveolar macrophages, but dedicate to convert from a replicated to a virulent state
Mechanism:
The ribosome-associated RelA, ppGpp synthetase, converts GTP to (p)ppGpp in response to amino acid depletion. The alarmone ppGpp stimulates the two-component system LetA/S, the transmission trait enhancer LetE, the alternative sigma factor RpoS and perhaps the putative master flagellar regulator RpoN, which together promote the expression of transmission traits: cytotoxic, motile, and infectious form
References:
Hammer BK, Swanson MS, 1999. Co-ordination of Legionella pneumophila virulence with entry into stationary phase by ppGpp. Mol. Microbiol. 33(4):721-731.
Zusman T, et al., 2002. Characterization of a Legionella pneumophila relA insertion mutant and toles of RelA and RpoS in virulence gene expression. J. Bacteriol. 184(1):67-75.
RpoS
Related genes: rpoS;
Keywords: Regulation;
Functions:
Stimulates intracellular replication and osmotic resistance and inhibits FliA-dependent traits
References:
Swanson MS, Hammer BK, 2000. Legionella pneumophila pathogesesis: a fateful journey from amoebae to macrophages. Annu. Rev. Microbiol. 54:567-613.
Bachman MA, Swanson MS, 2001. RpoS co-operates with other factors to induce Legionella pneumophila virulence in the stationary phase. Mol. Microbiol. 40(5):1201-1214.
Zusman T, et al., 2002. Characterization of a Legionella pneumophila relA insertion mutant and toles of RelA and RpoS in virulence gene expression. J. Bacteriol. 184(1):67-75.
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Bacteria
