Subsystem: Listeria Pathogenicity Island LIPI-1 extended
This subsystem's description is:
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|Diagram||Functional Roles||Subsystem Spreadsheet||Additional Notes|
Listeria main pathogenicity island LIPI-1 comprises 7 ORFs from lmo0200 to lmo0206 and carries virulence genes essential for intracellular parasitism. LIPI-1 is stably inserted at the same locus in genomes of pathogenic L. monocytogenes and L. ivanovii. It is missing from genomes of nonpathogenic L. innocua and L. welshimeri (apparently due to a deletion), and is corrupt in L. seeligeri. LIPI-1 has G+C composition similar to that of listerial core genome, lacks obvious traces of mobility factors, and its insertion locus is devoid of usual integration signals, such as tRNAs, repeats, etc (however, 2 small ORFs distantly related to viral proteins are located at its extreme right end). LIPI-1 appears ancient, acquired by common Listeria ancestor.
An attempt to extend this subsystem in order to identify related virulence factors in other microbial pathogens has revealed orthologs for the majority of Listeria proteins located within LIPI-1 in several Gram(+) pathogens - with a notable exception of ActA, which has no prokaryotic homologs. Surface protein ActA is necessary and sufficient for Listeria’s unique actin-based motility within the cytoplasm of an infected cell. ActA causes polymerization of host actin filaments at one pole of the bacterium into long tails that propel the bacteria through the cytoplasm. (Listeria and Shigella flexneri are the only two unrelated facultative intracellular pathogens which spread from cell to cell by using this mode of intracellular movement. However, IcsA (VirG) surface protein in S. flexneri required for this motility has no sequence similarity with ActA.) Evolutionary origin of ActA is not clear, but it contains functional domains that mimic the natural role of the mammalian Arp2/3 complex-activating proteins of the WASP/Scar family, involved in dynamic remodeling of actin cytoskeleton.
1 = full length pathogenicity island LIPI-1 is present in a genome
9 = Listeria species with LIPI-1 completely or partially deleted
2 = homolog of one or more proteins from LIPI-1 can be asserted in an organism other than Listeria
-1 = no homologs of any LIPI-1 proteins are evident in a genome
1. Vazquez-Boland JA, Dominguez-Bernal G, Gonzalez-Zorn B, Kreft J, Goebel W. 2001. Pathogenicity islands and virulence evolution in Listeria. Microbes Infect. 3(7):571-584. PMID: 11418331
2. Glaser P, et al., and Cossart P. 2001. Comparative genomics of Listeria species.
Science 294(5543):849-852. PMID: 11679669
3. A.A. Salyers and D.D. Whiott. Bacterial Pathogenesis. 2002. ASM Press, Herndon, VA.