Comparative Genomic Analysis of<i>Chlamydia trachomatis</i>Oculotropic and Genitotropic Strains

Carlson, John H.; Porcella, Stephen F.; McClarty, Grant; Caldwell, Harlan D.

doi:10.1128/iai.73.10.6407-6418.2005

Cited by 201 publications

(219 citation statements)

References 49 publications

Supporting

Mentioning

204

Contrasting

Order By: Relevance

“…The TARP orthologs demonstrate striking sequence diversity among C. trachomatis strains and species of Chlamydophila (7,28). Interestingly, the tyrosine-phosphorylated tandem repeat domain of TARP is not conserved between species, yet both the actin-binding helix and proline-rich oligomerization domains are conserved among the sequenced strains, suggesting that these domains are integral to the function of TARP (7,28).…”

Section: Discussionmentioning

confidence: 96%

“…Interestingly, the tyrosine-phosphorylated tandem repeat domain of TARP is not conserved between species, yet both the actin-binding helix and proline-rich oligomerization domains are conserved among the sequenced strains, suggesting that these domains are integral to the function of TARP (7,28). C. trachomatis L2 TARP contains a single actin-binding domain that is sufficient to promote actin polymerization.…”

Section: Discussionmentioning

confidence: 99%

“…C. trachomatis L2 TARP contains a single actin-binding domain that is sufficient to promote actin polymerization. C. trachomatis serovars D and A (28,29), respectively, contain two or three sequences nearly identical to the single L2 actin-binding domain. It will be of interest to compare the kinetics of actin polymerization among these TARP orthologs to determine whether polymerization rates correlate with observed differences in tissue tropism and͞or disease type.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Chlamydial TARP is a bacterial nucleator of actin

Jewett¹,

Fischer

Mead³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

166

223

View full text Add to dashboard Cite

Chlamydia trachomatis entry into host cells results from a parasitedirected remodeling of the actin cytoskeleton. A type III secreted effector, TARP (translocated actin recruiting phosphoprotein), has been implicated in the recruitment of actin to the site of internalization. To elucidate the role of TARP in actin recruitment, we identified host cell proteins that associated with recombinant GST-TARP fusions. TARP directly associated with actin, and this interaction promoted actin nucleation as determined by in vitro polymerization assays. Domain analysis of TARP identified an actin-binding domain that bears structural and primary amino acid sequence similarity to WH2 domain family proteins. In addition, a proline-rich domain was found to promote TARP oligomerization and was required for TARP-dependent nucleation of new actin filaments. Our findings reveal a mechanism by which chlamydiae induce localized cytoskeletal changes by the translocated effector TARP during entry into host cells.Chlamydia ͉ type III secretion ͉ cytoskeleton ͉ endocytosis A Gram-negative obligate intracellular bacterium, Chlamydia trachomatis, is the leading cause of preventable blindness worldwide and the most prevalent bacterial pathogen causing sexually transmitted disease in the western world (1). Chlamydiae initiate their intracellular developmental cycle by actively gaining entry into host cells. The extracellular infectious form of the developmental cycle is referred to as an elementary body (EB). Once engulfed by the host cell, the EB differentiates into the replicative reticulate body within the protective confines of a membrane-bound parasitophorous vacuole called an inclusion (2).The ligands on the EB surface and cognate host cell receptor have not been definitively identified; however, it appears that chlamydiae use an entry mechanism that involves several distinct levels of interaction (3, 4). EB invasion of nonphagocytic cells is thus the product of coordinated cytoskeletal remodeling characterized by the formation of pedestal-like structures and hypertrophic microvilli that are directly triggered by the invading chlamydiae (5).A recently identified C. trachomatis type III secretion system secreted protein called TARP (for translocated actin recruiting phosphoprotein) is tyrosine-phosphorylated by a host cell kinase and is spatially and temporally associated with the recruitment of actin at the site of EB invasion (6). TARP is present in all pathogenic Chlamydia species examined to date. Analysis of TARP orthologs from C. trachomatis, Chlamydia muridarium, Chlamydia caviae, and Chlamydia pneumoniae indicates that only C. trachomatis serovars are phosphorylated, despite all Chlamydia strains demonstrating the recruitment of actin to the site of entry (6, 7).We demonstrate here that TARP associates directly with actin by a small domain contained within the C-terminal region of the protein. Furthermore, TARP independently nucleates new actin filaments by forming a large homogenous multimeric protein complex mediated by a prolin...

show abstract

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Chlamydial TARP is a bacterial nucleator of actin

Jewett¹,

Fischer

Mead³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

166

223

View full text Add to dashboard Cite

show abstract

“…C. trachomatis strains are tryptophan auxotrophs. Paradoxically, genitotropic but not oculotropic strains have retained a functional trpBA operon (18)(19)(20)(21). The trpBA operon is negatively regulated and expresses the TrpBA tryptophan synthase that uses exogenous indole as substrate to synthesize tryptophan and escape the anti-microbial effect of IFN-γ-mediated tryptophan starvation (20,21).…”

Section: Resultsmentioning

confidence: 99%

Generation of targeted Chlamydia trachomatis null mutants

Kari

Goheen

Randall

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

133

135

View full text Add to dashboard Cite

Chlamydia trachomatis is an obligate intracellular bacterial pathogen that infects hundreds of millions of individuals globally, causing blinding trachoma and sexually transmitted disease. More effective chlamydial control measures are needed, but progress toward this end has been severely hampered by the lack of a tenable chlamydial genetic system. Here, we describe a reversegenetic approach to create isogenic C. trachomatis mutants. C. trachomatis was subjected to low-level ethyl methanesulfonate mutagenesis to generate chlamydiae that contained less then one mutation per genome. Mutagenized organisms were expanded in small subpopulations that were screened for mutations by digesting denatured and reannealed PCR amplicons of the target gene with the mismatch specific endonuclease CEL I. Subpopulations with mutations were then sequenced for the target region and plaque-cloned if the desired mutation was detected. We demonstrate the utility of this approach by isolating a tryptophan synthase gene (trpB) null mutant that was otherwise isogenic to its parental clone as shown by de novo genome sequencing. The mutant was incapable of avoiding the anti-microbial effect of IFN-γ-induced tryptophan starvation. The ability to genetically manipulate chlamydiae is a major advancement that will enhance our understanding of chlamydial pathogenesis and accelerate the development of new anti-chlamydial therapeutic control measures. Additionally, this strategy could be applied to other medically important bacterial pathogens with no or difficult genetic systems.genetics | mutation screen

show abstract

“…The apparently elevated concentrations of novobiocin required to suppress chlamydial replication were striking. However, each of the chlamydial strains for which genome sequencing has been completed [C. trachomatis strain D/UW-3Cx (Stephens et al, 1998), C. trachomatis strain A/HAR-13 (Carlson et al, 2005) and C. muridarum strain Nigg (Read et al, 2000)] carries phospholipase D family orthologues (CT154-158; CTA_0163-0167 and TC0432-436; TC0440, respectively). In Escherichia coli, phospholipase D is encoded by cls.…”

Section: Novobiocin Is An Effective Curing Agent For Chlamydiaementioning

confidence: 99%

A plasmid-cured Chlamydia muridarum strain displays altered plaque morphology and reduced infectivity in cell culture

2006

View full text Add to dashboard Cite

A highly conserved cryptic plasmid is present in Chlamydia trachomatis yet naturally occurring plasmid-deficient isolates are very rare. This paper describes the isolation and characterization of a plasmid-deficient strain of C. muridarum, using novobiocin as a curing agent. Plasmid-deficient derivatives of C. muridarum strain Nigg were generated at high efficiencies (4-30 %). Phenotypic characterization revealed that the cured derivative was unable to accumulate glycogen within intracytoplasmic inclusions. In addition, this strain formed small plaques at a reduced efficiency compared to the wild-type parent.

show abstract

Comparative Genomic Analysis ofChlamydia trachomatisOculotropic and Genitotropic Strains

Cited by 201 publications

References 49 publications

Chlamydial TARP is a bacterial nucleator of actin

Chlamydial TARP is a bacterial nucleator of actin

Generation of targeted Chlamydia trachomatis null mutants

A plasmid-cured Chlamydia muridarum strain displays altered plaque morphology and reduced infectivity in cell culture

Contact Info

Product

Resources

About