Disruption of the mycobacterial cell entry gene of<i>Mycobacterium bovis</i>BCG results in a mutant that exhibits a reduced invasiveness for epithelial cells

Flesselles, Bruno; Anand, N.N.; Remani, Jack; Loosmore, Sheena M.; Klein, Michel

doi:10.1111/j.1574-6968.1999.tb13738.x

Cited by 51 publications

(13 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Interestingly, in contrast to pathogenic M. avium TMC724, conditionally pathogenic M. avium 104 contains 2 additional clusters of mce genes, MAV_2532-2537 and MAV_5047-5051 located in LSPs 14 and 22, respectively. The mce operons have been implicated in the pathogenesis of mycobacteria, and their products were suggested to be transporter systems [29], [30], [31], [32].…”

Section: Resultsmentioning

confidence: 99%

RNA-Seq Analysis of Mycobacterium avium Non-Coding Transcriptome

et al. 2013

View full text Add to dashboard Cite

Deep sequencing was implemented to study the transcriptional landscape of Mycobacterium avium. High-resolution transcriptome analysis identified the transcription start points for 652 genes. One third of these genes represented leaderless transcripts, whereas the rest of the transcripts had 5′ UTRs with the mean length of 83 nt. In addition, the 5′ UTRs of 6 genes contained SAM-IV and Ykok types of riboswitches. 87 antisense RNAs and 10 intergenic small RNAs were mapped. 6 intergenic small RNAs, including 4.5S RNA and rnpB, were transcribed at extremely high levels. Although several intergenic sRNAs are conserved in M. avium and M. tuberculosis, both of these species have unique intergenic sRNAs. Moreover, we demonstrated that even conserved small RNAs are regulated differently in these species. Different sets of intergenic sRNAs may underlie differences in physiology between conditionally pathogenic M. avium and highly specialized pathogen M. tuberculosis.

show abstract

Section: Resultsmentioning

confidence: 99%

RNA-Seq Analysis of Mycobacterium avium Non-Coding Transcriptome

et al. 2013

View full text Add to dashboard Cite

show abstract

“…We screened this list initially for the presence of genes previously shown to be required for survival of mycobacteria in macrophages. Insertions with a high fitness cost include those in a known virulence locus involved in synthesis and transport of phthiocerol dimycocerosate (DIM), a complex lipid component of the mycobacterial cell wall [32,33], and in the mycobacterial cell entry 1 (mce1) region (Rv0169–Rv0178), which has been implicated in mycobacterial entry to host cells [35–37] and is required for virulence in a mouse model (Figure 2) [30]. Reduced fitness (FR < 0.5; false discovery rate [FDR] = 1%) was also associated with a series of insertions in the pathway for conversion of isocitrate to glucose (Table S3)—isocitrate lyase ( icl, Rv0467), PEP carboxykinase ( pcka, Rv0211) and fructose-1,6-bisphosphatase (Rv1099c)—consistent with previous proposals that mycobacteria rely predominantly on lipid substrates for intracellular metabolism [38].…”

Section: Resultsmentioning

confidence: 99%

Mycobacterial Mutants with Defective Control of Phagosomal Acidification

et al. 2005

View full text Add to dashboard Cite

The pathogenesis of mycobacterial infection is associated with an ability to interfere with maturation of the phagosomal compartment after ingestion by macrophages. Identification of the mycobacterial components that contribute to this phenomenon will allow rational design of novel approaches to the treatment and prevention of tuberculosis. Microarray-based screening of a transposon library was used to identify mutations that influence the fate of Mycobacterium bovis bacille Calmette-Guérin (BCG) following uptake by macrophages. A screen based on bacterial survival during a 3-d infection highlighted genes previously implicated in growth of Mycobacterium tuberculosis in macrophages and in mice, together with a number of other virulence genes including a locus encoding virulence-associated membrane proteins and a series of transporter molecules. A second screen based on separation of acidified and non-acidified phagosomes by flow cytometry identified genes involved in mycobacterial control of early acidification. This included the KefB potassium/proton antiport. Mutants unable to control early acidification were significantly attenuated for growth during 6-d infections of macrophages. Early acidification of the phagosome is associated with reduced survival of BCG in macrophages. A strong correlation exists between genes required for intracellular survival of BCG and those required for growth of M. tuberculosis in mice. In contrast, very little correlation exists between genes required for intracellular survival of BCG and those that are up-regulated during intracellular adaptation of M. tuberculosis. This study has identified targets for interventions to promote immune clearance of tuberculosis infection. The screening technologies demonstrated in this study will be useful to the study of pathogenesis in many other intracellular microorganisms.

show abstract

“…A considerable number of studies have demonstrated that Mce proteins are related to the virulence of each member of the M. tuberculosis complex. Flesselles et al [5] have reported that a BCG strain mutated in mce1 exhibits a reduced ability to invade the non-phagocytic epithelial cell line HeLa. Sassetti and Rubin [6] have then found that mce1 disruption causes attenuation of M. tuberculosis .…”

Section: Introductionmentioning

confidence: 99%

Study of the in vivo role of Mce2R, the transcriptional regulator of mce2 operon in Mycobacterium tuberculosis

Forrellad¹,

Bianco²,

Blanco³

et al. 2013

BMC Microbiol

View full text Add to dashboard Cite

BackgroundTuberculosis is one of the leading causes of mortality throughout the world. Mycobacterium tuberculosis, the agent of human tuberculosis, has developed strategies involving proteins and other compounds called virulence factors to subvert human host defences and damage and invade the human host. Among these virulence-related proteins are the Mce proteins, which are encoded in the mce1, mce2, mce3 and mce4 operons of M. tuberculosis. The expression of the mce2 operon is negatively regulated by the Mce2R transcriptional repressor. Here we evaluated the role of Mce2R during the infection of M. tuberculosis in mice and macrophages and defined the genes whose expression is in vitro regulated by this transcriptional repressor.ResultsWe used a specialized transduction method for generating a mce2R mutant of M. tuberculosis H37Rv. Although we found equivalent replication of the MtΔmce2R mutant and the wild type strains in mouse lungs, overexpression of Mce2R in the complemented strain (MtΔmce2RComp) significantly impaired its replication. During in vitro infection of macrophages, we observed a significantly increased association of the late endosomal marker LAMP-2 to MtΔmce2RComp-containing phagosomes as compared to MtΔmce2R and the wild type strains. Whole transcriptional analysis showed that Mce2R regulates mainly the expression of the mce2 operon, in the in vitro conditions studied.ConclusionsThe findings of the current study indicate that Mce2R weakly represses the in vivo expression of the mce2 operon in the studied conditions and argue for a role of the proteins encoded in Mce2R regulon in the arrest of phagosome maturation induced by M. tuberculosis.

show abstract

Disruption of the mycobacterial cell entry gene ofMycobacterium bovisBCG results in a mutant that exhibits a reduced invasiveness for epithelial cells

Cited by 51 publications

References 11 publications

RNA-Seq Analysis of Mycobacterium avium Non-Coding Transcriptome

RNA-Seq Analysis of Mycobacterium avium Non-Coding Transcriptome

Mycobacterial Mutants with Defective Control of Phagosomal Acidification

Study of the in vivo role of Mce2R, the transcriptional regulator of mce2 operon in Mycobacterium tuberculosis

Contact Info

Product

Resources

About