Size and genomic location of the pMGA multigene family of Mycoplasma gallisepticum

Baseggio, Nina; Glew, Michelle D.; Markham, Philip F.; Whithear, Kevin G.; Browning, Glenn F.

doi:10.1099/13500872-142-6-1429

Cited by 56 publications

(52 citation statements)

References 21 publications

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“…The nature of the disease state caused by M. gallisepticum is chronic, indicating that the organisms are accomplished at evading the immune system of their host. Although much of this evasion can be attributed to antigenic variation (2,12,22), it is possible that a secondary evasive mechanism exists. Evidence suggests that M. gallisepticum may enter epithelial cells and exist within them before rapidly exiting (48).…”

Section: Vol 74 2006 Fibronectin-binding Proteins In M Gallisepticmentioning

confidence: 99%

Identification of Fibronectin-Binding Proteins inMycoplasma gallisepticumStrain R

May

Papazisi²,

Gorton

et al. 2006

Infect Immun

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We have determined that virulent Mycoplasma gallisepticum strain R low is capable of binding the extracellular matrix protein fibronectin. Fibronectin was found to be present in M. gallisepticum R low protein extracts by Western blotting and peptide sequencing. Mycoplasma gallisepticum R high , the attenuated, high-passage derivative of R low , is deficient in this ability. MGA_1199, the M. gallisepticum homologue of the cytadherenceassociated protein P65 from Mycoplasma pneumoniae, and MGA_0928, the M. gallisepticum homologue of the M. pneumoniae cytoskeletal protein HMW3, were identified as fibronectin-binding proteins. Peptides from the regions of MGA_1199 and MGA_0928 exhibiting the highest degree of homology with known fibronectinbinding proteins were shown to bind the gelatin/heparin-binding domain of fibronectin. MGA_1199 and MGA_0928 were shown to be absent and aberrant, respectively, in R high , explaining its lack of fibronectinbinding capability. Consistent with its M. pneumoniae counterpart, MGA_1199 (renamed PlpA) was demonstrated to be surface exposed, despite a lack of classical membrane-spanning domains. Due to its demonstrated topology and the strength of interaction between its binding peptide and fibronectin, we propose that PlpA functions as a fibronectin-binding protein in vivo and may possess atypical transmembrane domains.The avian pathogen Mycoplasma gallisepticum is known to cause chronic respiratory disease in chickens, infectious sinusitis in turkeys, and conjunctivitis in finches (23,33,45,49). The chronic nature of the infection and its effects on weight and egg production render it a pathogen of considerable economic importance to the poultry industry (49). Mycoplasma gallisepticum, together with Mycoplasma pneumoniae and Mycoplasma genitalium, is one of the three most prominent members of the M. pneumoniae phylogenetic cluster. Members of this cluster are pathogens that establish chronic infections and mediate attachment to the host epithelium via molecules present on a complex tip structure (33). The proteins that compose the tip structure, as well as a model for its assembly, have been described using M. pneumoniae (1,18,19).The virulence of strain R has been previously examined by comparing the virulent, low-passage strain (R low ) with the attenuated, high-passage strain (R high ) (29). Initial examination of the protein profiles of R low and R high indicated that three proteins were absent in R high . These proteins have been identified as the primary cytadhesin GapA, the cytadherence-related molecule CrmA, and a high-affinity transport protein, HatA (29,44). Complementation experiments with R high using wild-type gapA and crmA demonstrated that coexpression of GapA and CrmA is essential for cytadherence in M. gallisepticum (27); however, these attachment molecules were not able to completely restore virulence, suggesting that additional differences contribute to the attenuation of the high-passage isolate.With this in mind, we more closely examined the protein profiles of R l...

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Section: Vol 74 2006 Fibronectin-binding Proteins In M Gallisepticmentioning

confidence: 99%

Identification of Fibronectin-Binding Proteins inMycoplasma gallisepticumStrain R

May

Papazisi²,

Gorton

et al. 2006

Infect Immun

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“…Removal of antibody from culture medium then resulted in the reexpression of pMGA1.1 (15). The transcriptional switching between pMGA genes was shown to be unequivocally associated with changes in the length of a unique trinucleotide GAA repeat (9), a motif found to be common to all pMGA genes (2). Specifically, a (GAA) 12 motif 5Ј to a pMGA1.1 promoter was shown to be an obligate requirement for the expression of that gene (9).…”

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confidence: 99%

“…Each M. gallisepticum strain usually expresses only one homogeneous, unique pMGA molecule (8), which in strain S6, the subject of this study, has been designated pMGA1.1 (13,14). All strains thus far analyzed contain large pMGA multigene families ranging in size from 32 to 70 genes (2). In strain S6, all such genes contain a putative promoter motif (8) and many possess an uninterrupted open reading frame (14).…”

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confidence: 99%

pMGA Phenotypic Variation in Mycoplasma gallisepticum Occurs In Vivo and Is Mediated by Trinucleotide Repeat Length Variation

et al. 2000

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Chickens were infected with a pathogenic strain of Mycoplasma gallisepticum, and the expression of pMGA, the major surface protein, was inferred by examination of colonies from ex vivo cells. Within 2 days postinfection, 40% of cells had ceased the expression of the original pMGA surface protein (pMGA1.1), and by day 6, the majority of recovered cells were in this category. The switch in pMGA phenotype which had occurred in vivo was reversible, since most colonies produced from ex vivo progenitors exhibited frequent pMGA1.1 ؉ sectors. After prolonged in vivo habitation, increasing proportions of recovered cells gave rise to variant pMGA colonies which had switched from the expression of pMGA1.1 to another gene, pMGA1.2, concomitant with the acquisition of a (GAA) 12 motif 5 to its promoter. Collectively, the results suggest that changes in M. gallisepticum pMGA gene expression in vivo are normal, common, and possibly obligate events for successful colonization of the host. Surprisingly, the initial cessation of pMGA1.1 expression occurred in the absence of detectable pMGA antibodies and seemed to precede the adaptive immune response.

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“…The presence of multiple adhesins in other mycoplasma pathogens has been well described. Such Mycoplasma species contain adhesins located in operons (19), with multiple copies of adhesin genes present in the genome (20,21). The presence of multiple adhesins increases antigenic variation which is advantageous for avoiding recognition by the immune system (5).…”

mentioning

confidence: 99%

A Processed Multidomain Mycoplasma hyopneumoniae Adhesin Binds Fibronectin, Plasminogen, and Swine Respiratory Cilia

Seymour¹,

Deutscher

Jenkins

et al. 2010

Journal of Biological Chemistry

134

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Porcine enzootic pneumonia is a chronic respiratory disease that affects swine. The etiological agent of the disease, Mycoplasma hyopneumoniae, is a bacterium that adheres to cilia of the swine respiratory tract, resulting in loss of cilia and epithelial cell damage. A M. hyopneumoniae protein P116, encoded by mhp108, was investigated as a potential adhesin. Examination of P116 expression using proteomic analyses observed P116 as a full-length protein and also as fragments, ranging from 17 to 70 kDa in size. A variety of pathogenic bacterial species have been shown to bind the extracellular matrix component fibronectin as an adherence mechanism. M. hyopneumoniae cells were found to bind fibronectin in a dose-dependent and saturable manner. Surface plasmon resonance was used to show that a recombinant C-terminal domain of P116 bound fibronectin at physiologically relevant concentrations (K D 24 ؎ 6 nM). Plasmin(ogen)-binding proteins are also expressed by many bacterial pathogens, facilitating extracellular matrix degradation. M. hyopneumoniae cells were found to also bind plasminogen in a dose-dependent and saturable manner; the C-terminal domain of P116 binds to plasminogen (K D 44 ؎ 5 nM). Plasminogen binding was abolished when the C-terminal lysine of P116 was deleted, implicating this residue as part of the plasminogen binding site. P116 fragments adhere to the PK15 porcine kidney epithelial-like cell line and swine respiratory cilia. Collectively these data suggest that P116 is an important adhesin and virulence factor of M. hyopneumoniae.

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Size and genomic location of the pMGA multigene family of Mycoplasma gallisepticum

Cited by 56 publications

References 21 publications

Identification of Fibronectin-Binding Proteins inMycoplasma gallisepticumStrain R

Identification of Fibronectin-Binding Proteins inMycoplasma gallisepticumStrain R

pMGA Phenotypic Variation in Mycoplasma gallisepticum Occurs In Vivo and Is Mediated by Trinucleotide Repeat Length Variation

A Processed Multidomain Mycoplasma hyopneumoniae Adhesin Binds Fibronectin, Plasminogen, and Swine Respiratory Cilia

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