scholarly journals Amended Description of the Genes for Synthesis of Actinomyces naeslundii T14V Type 1 Fimbriae and Associated Adhesin

2007 ◽  
Vol 75 (8) ◽  
pp. 4181-4185 ◽  
Author(s):  
Ping Chen ◽  
John O. Cisar ◽  
Sonja Hess ◽  
Jenny T. C. Ho ◽  
Kai P. Leung
Keyword(s):  
Tooth Surface ◽  
Gram Positive ◽  
Type 1 Fimbriae ◽  
Actinomyces Naeslundii ◽  
Fimbrial Subunit ◽  
Structural Subunit ◽  
A Minor

ABSTRACT The type 1 fimbriae of Actinomyces naeslundii T14V mediate adhesion of this gram-positive species to the tooth surface. The present findings show that the locus for type 1 fimbria production in this strain includes three genes, fimQ for a minor fimbrial subunit that appears to be an adhesin, fimP for the major structural subunit, and srtC1 for a type 1 fimbria-specific sortase involved in the assembly of these structures.

scholarly journals Sortase-Catalyzed Assembly of Distinct Heteromeric Fimbriae in Actinomyces naeslundii

2007 ◽  
Vol 189 (8) ◽  
pp. 3156-3165 ◽  
Author(s):  
Arunima Mishra ◽  
Asis Das ◽  
John O. Cisar ◽  
Hung Ton-That
Keyword(s):  
Gene Cluster ◽  
Biochemical Analysis ◽  
Gene Clusters ◽  
Oral Diseases ◽  
Actinomyces Naeslundii ◽  
Molecular Investigation ◽  
A Minor ◽  
Assembly Pathways

ABSTRACT Two types of adhesive fimbriae are expressed by Actinomyces; however, the architecture and the mechanism of assembly of these structures remain poorly understood. In this study we characterized two fimbrial gene clusters present in the genome of Actinomyces naeslundii strain MG-1. By using immunoelectron microscopy and biochemical analysis, we showed that the fimQ-fimP-srtC1-fimR gene cluster encodes a fimbrial structure (designated type 1) that contains a major subunit, FimP, forming the shaft and a minor subunit, FimQ, located primarily at the tip. Similarly, the fimB-fimA-srtC2 gene cluster encodes a distinct fimbrial structure (designated type 2) composed of a shaft protein, FimA, and a tip protein, FimB. By using allelic exchange, we constructed an in-frame deletion mutant that lacks the SrtC2 sortase. This mutant produces abundant type 1 fimbriae and expresses the monomeric FimA and FimB proteins, but it does not assemble type 2 fimbriae. Thus, SrtC2 is a fimbria-specific sortase that is essential for assembly of the type 2 fimbriae. Together, our experiments pave the way for several lines of molecular investigation that are necessary to elucidate the fimbrial assembly pathways in Actinomyces and their function in the pathogenesis of different biofilm-related oral diseases.

scholarly journals Enhanced virulence of Escherichia coli bearing a site-targeted mutation in the major structural subunit of type 1 fimbriae.

1993 ◽  
Vol 61 (5) ◽  
pp. 1667-1673 ◽  
Author(s):  
A K May ◽  
C A Bloch ◽  
R G Sawyer ◽  
M D Spengler ◽  
T L Pruett
Keyword(s):  
Escherichia Coli ◽  
Type 1 Fimbriae ◽  
Targeted Mutation ◽  
Structural Subunit ◽  
A Site

scholarly journals Type 1 fimbriae in commensal Escherichia coli derived from healthy humans.

2014 ◽  
Vol 61 (2) ◽  
Author(s):  
Paweł Pusz ◽  
Ewa Bok ◽  
Justyna Mazurek ◽  
Michał Stosik ◽  
Katarzyna Baldy-Chudzik
Keyword(s):  
Escherichia Coli ◽  
Gene Encoding ◽  
E Coli ◽  
Type 1 Fimbriae ◽  
Healthy Humans ◽  
Chaperone Protein ◽  
Genes Expression ◽  
Structural Subunit ◽  
Complete Set

Type 1 fimbriae are one of the most important factors of Escherichia coli adaptation to different niches in the host. Our study indicated that the genetic marker--fimH gene occurred commonly in commensal E. coli derived from healthy humans but expression of the type 1 fimbriae was not observed. Identification of fim structural subunit genes (fimA-fimH) and recombinase fimE and fimB genes showed that many of the strains were carrying an incomplete set of genes and the genes expression study revealed that in strains with complete set of fim genes, the fimC gene, encoding the chaperone protein, was not expressed.

scholarly journals Actinomyces naeslundii Displays VariantfimP and fimA Fimbrial Subunit Genes Corresponding to Different Types of Acidic Proline-Rich Protein and β-Linked Galactosamine Binding Specificity

1998 ◽  
Vol 66 (9) ◽  
pp. 4403-4410 ◽  
Author(s):  
K. Hallberg ◽  
C. Holm ◽  
U. Öhman ◽  
N. Strömberg
Keyword(s):  
Molecular Basis ◽  
Binding Specificity ◽  
Actinomyces Naeslundii ◽  
Fimbrial Subunit ◽  
Streptococcus Oralis ◽  
Binding Preference ◽  
Different Types ◽  
Preferential Binding

ABSTRACT Actinomyces naeslundii genospecies 1 and 2 bind to acidic proline-rich proteins (APRPs) and statherin via type 1 fimbriae and to β-linked galactosamine (GalNAcβ) structures via type 2 fimbriae. In addition, A. naeslundii displays two types of binding specificity for both APRPs-statherin and GalNAcβ, while Actinomyces odontolyticusbinds to unknown structures. To study the molecular basis for these binding specificities, DNA fragments spanning the entire or central portions of fimP (type 1) and fimA (type 2) fimbrial subunit genes were amplified by PCR from strains of genospecies 1 and 2 and hybridized with DNA from two independent collections of oral Actinomyces isolates. Isolates of genospecies 1 and 2 and A. odontolyticus, but no otherActinomyces species, were positive for hybridization withfimP and fimA full-length probes irrespective of binding to APRPs and statherin, GalNAcβ, or unknown structures. Isolates of genospecies 1 and 2, with deviating patterns of GalNAcβ1-3Galα-O-ethyl-inhibitable coaggregation with Streptococcus oralis Ss34 and MPB1, were distinguished by a fimA central probe from genospecies 1 and 2, respectively. Furthermore, isolates of genospecies 1 and 2 displaying preferential binding to APRPs over statherin were positive with a fimP central probe, while a genospecies 2 strain with the opposite binding preference was not. The sequences offimP and fimA central gene segments were highly conserved among isolates with the same, but diversified between those with a variant, binding specificity. In conclusion, A. naeslundii exhibits variant fimP andfimA genes corresponding to diverse APRP and GalNAcβ specificities, respectively, while A. odontolyticus has a genetically related but distinct adhesin binding specificity.

scholarly journals The Late-Domain-Containing Protein p6 Is the Predominant Phosphoprotein of Human Immunodeficiency Virus Type 1 Particles

2002 ◽  
Vol 76 (3) ◽  
pp. 1015-1024 ◽  
Author(s):  
Barbara Müller ◽  
Tilo Patschinsky ◽  
Hans-Georg Kräusslich
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Metabolic Labeling ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
A Minor ◽  
Hiv 1

ABSTRACT The Gag-derived protein p6 of human immunodeficiency virus type 1 (HIV-1) plays a crucial role in the release of virions from the membranes of infected cells. It is presumed that p6 and functionally related proteins from other viruses act as adapters, recruiting cellular factors to the budding site. This interaction is mediated by so-called late domains within the viral proteins. Previous studies had suggested that virus release from the plasma membrane shares elements with the cellular endocytosis machinery. Since protein phosphorylation is known to be a regulatory mechanism in these processes, we have investigated the phosphorylation of HIV-1 structural proteins. Here we show that p6 is the major phosphoprotein of HIV-1 particles. After metabolic labeling of infected cells with [ortho- 32P]phosphate, we found that phosphorylated p6 from infected cells and from virus particles consisted of several forms, suggesting differential phosphorylation at multiple sites. Apparently, phosphorylation occurred shortly before or after the release of p6 from Gag and involved only a minor fraction of the total virion-associated p6 molecules. Phosphoamino acid analysis indicated phosphorylation at Ser and Thr, as well as a trace of Tyr phosphorylation, supporting the conclusion that multiple phosphorylation events do occur. In vitro experiments using purified virus revealed that endogenous or exogenously added p6 was efficiently phosphorylated by virion-associated cellular kinase(s). Inhibition experiments suggested that a cyclin-dependent kinase or a related kinase, most likely ERK2, was involved in p6 phosphorylation by virion-associated enzymes.

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