June R. Scott

Use of the Lactococcal nisA Promoter To Regulate Gene Expression in Gram-Positive Bacteria: Comparison of Induction Level and Promoter Strength (1998)

Eichenbaum, Zehava, Federle, Michael J., Marra, Diana, Vos, Willem M. De, Kuipers, Oscar P., Kleerebezem, Michiel, ...

We characterized the regulated activity of the lactococcal nisA promoter in strains of the gram-positive species Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae,...

A conserved residue in the tip proteins of CS1 and CFA/I pili of enterotoxigenic Escherichia coli that is essential for adherence

Sakellaris, Harry, Munson, George P., Scott, June R.

Enterotoxigenic Escherichia coli associated with human diarrheal disease utilize any of a limited group of serologically distinguishable pili for attachment to intestinal cells. These include CS1 and...

CooB plays a chaperone-like role for the proteins involved in formation of CS1 pili of enterotoxigenic Escherichia coli

Voegele, Karl, Sakellaris, Harry, Scott, June R.

CS1 pili serve as the prototype of a class of filamentous appendages found on the surface of strains of enterotoxigenic Escherichia coli. The four genes needed to synthesize functional CS1 pili in E....

Excision of the Conjugative Transposon Tn916 in Lactococcus lactis

Marra, Diana, Smith, Jennifer G., Scott, June R.

In Lactococcus lactis excision of Tn916 is limited by the concentration of integrase and is increased by providing more excisionase. However, even with increased excision of Tn916 in L. lactis, no...

The Level of Expression of the Minor Pilin Subunit, CooD, Determines the Number of CS1 Pili Assembled on the Cell Surface of Escherichia coli

Sakellaris, Harry, Penumalli, Vikram R., Scott, June R.

CooD, the minor subunit of CS1 pili of enterotoxigenic Escherichia coli, is essential for the assembly of stable, functional pili. We previously proposed that CooD is a rate-limiting initiator of CS1...

Binding Site Recognition by Rns, a Virulence Regulator in the AraC Family

Munson, George P., Scott, June R.

The expression of CS1 pili by enterotoxigenic strains of Escherichia coli is regulated at the transcriptional level and requires the virulence regulator Rns, a member of the AraC family of regulatory...

A Response Regulator That Represses Transcription of Several Virulence Operons in the Group A Streptococcus

Federle, Michael J., McIver, Kevin S., Scott, June R.

A search for homologs of the Bacillus subtilis PhoP response regulator in the group A streptococcus (GAS) genome revealed three good candidates. Inactivation of one of these, recently identified as...

Regulation of mga Transcription in the Group A Streptococcus: Specific Binding of Mga within Its Own Promoter and Evidence for a Negative Regulator

McIver, Kevin S., Thurman, Alec S., Scott, June R.

Transcription of mga, encoding the multiple virulence gene regulator of the group A streptococcus, is positively autoregulated. This regulation requires a DNA region (Pmga) that contains both a...

The Frequency of Conjugative Transposition of Tn916 Is Not Determined by the Frequency of Excision

Marra, Diana, Pethel, Beth, Churchward, Gordon G., Scott, June R.

Excision and formation of a covalently closed circular transposon molecule are required for conjugative transposition of Tn916 but are not the only factors that limit the frequency of conjugative...

Attenuated Expression of the mga Virulence Regulon in an M Serotype 50 Mouse-Virulent Group A Streptococcal Strain

Yung, Der-Li, McIver, Kevin S., Scott, June R., Hollingshead, Susan K.

The attenuated expression of virulence genes found in a group A streptococcal strain that is naturally pathogenic for mice was postulated to result from a defect in the strain's multigene regulator,...

Role of Streptolysin O in a Mouse Model of Invasive Group A Streptococcal Disease

Limbago, Brandi, Penumalli, Vikram, Weinrick, Brian, Scott, June R.

Many of the virulence factors that have been characterized for group A streptococci (GAS) are not expressed in all clinical isolates. One putative virulence factor that is present among most is...

Novel Group of Virulence Activators within the AraC Family That Are Not Restricted to Upstream Binding Sites

Munson, George P., Holcomb, Lisa G., Scott, June R.

Several regulators within the AraC family control the expression of genes known or thought to be required for virulence of bacterial pathogens. One of these, Rns, activates transcription from an...

Restoration of Mga Function to a Streptococcus pyogenes Strain (M Type 50) That Is Virulent in Mice

Limbago, Brandi, McIver, Kevin S., Penumalli, Vikram, Weinrick, Brian, Scott, June R.

The Mga protein in B514Sm, a Streptococcus pyogenes strain isolated as a mouse pathogen, contains amino acid substitutions at conserved sites that render the protein defective. Replacement of mga50...

Generation and Surface Localization of Intact M Protein in Streptococcus pyogenes Are Dependent on sagA

Biswas, Indranil, Germon, Pierre, McDade, Kathleen, Scott, June R.

The M protein is an important surface-located virulence factor of Streptococcus pyogenes, the group A streptococcus (GAS). Expression of M protein is primarily controlled by Mga, a transcriptional...

Use of the Lactococcal nisA Promoter To Regulate Gene Expression in Gram-Positive Bacteria: Comparison of Induction Level and Promoter Strength

Eichenbaum, Zehava, Federle, Michael J., Marra, Diana, De Vos, Willem M., Kuipers, Oscar P., Kleerebezem, Michiel, ...

We characterized the regulated activity of the lactococcal nisA promoter in strains of the gram-positive species Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae,...

Virulence control in group A Streptococcus by a two-component gene regulatory system: Global expression profiling and in vivo infection modeling

Graham, Morag R., Smoot, Laura M., Migliaccio, Cristi A. Lux, Virtaneva, Kimmo, Sturdevant, Daniel E., Porcella, Stephen F., ...

Two-component gene regulatory systems composed of a membrane-bound sensor and cytoplasmic response regulator are important mechanisms used by bacteria to sense and respond to environmental stimuli....

In Vitro Identification of Rns-Regulated Genes

Munson, George P., Holcomb, Lisa G., Alexander, Heather L., Scott, June R.

To identify Rns-regulated genes, a maltose binding protein (MBP)-Rns fusion protein was used to isolate DNA fragments from enterotoxigenic Escherichia coli genomic DNA that carry Rns binding sites....

Differential Recognition of Surface Proteins in Streptococcus pyogenes by Two Sortase Gene Homologs

Barnett, Timothy C., Scott, June R.

The interaction of Streptococcus pyogenes (group A streptococcus [GAS]) with its human host requires several surface proteins. In this study, we isolated mutations in a gene required for the surface...

Identification of rocA, a Positive Regulator of covR Expression in the Group A Streptococcus

Biswas, Indranil, Scott, June R.

In the group A streptococcus (GAS; Streptococcus pyogenes), a two-component system known as CovRS (or CsrRS) regulates about 15% of the genes, including several important virulence factors like the...

Expression of the Secondary Sigma Factor σX in Streptococcus pyogenes Is Restricted at Two Levels

Opdyke, Jason A., Scott, June R.

Secondary RNA polymerase sigma factors in many bacteria are responsible for regulating a vast range of processes including virulence. A protein (σX) in the gram-positive human pathogen Streptococcus...

Mutants of Plasmid Prophage P1 with Elevated Copy Number: Isolation and Characterization

Scott, June R., Kropf, Martha M., Padolsky, Linda, Goodspeed, James K., Davis, Richard, Vapnek, Daniel

A series of mutations of the P1 plasmid prophage that lead to increased copy number was isolated and analyzed. The copy number of the mutants was elevated at least five- to eightfold relative to...

Horizontal Transfer of CS1 Pilin Genes of Enterotoxigenic Escherichia coli

Froehlich, Barbara, Holtzapple, Erik, Read, Timothy D., Scott, June R.

CS1 is one of a limited number of serologically distinct pili found in enterotoxigenic Escherichia coli (ETEC) strains associated with disease in people. The genes for the CS1 pilus are on a large...

CovS Inactivates CovR and Is Required for Growth under Conditions of General Stress in Streptococcus pyogenes

Dalton, Tracy L., Scott, June R.

The gram-positive human pathogen Streptococcus pyogenes (group A streptococcus [GAS]) causes diseases ranging from mild and often self-limiting infections of the skin or throat to invasive and...

A Novel Sortase, SrtC2, from Streptococcus pyogenes Anchors a Surface Protein Containing a QVPTGV Motif to the Cell Wall

Barnett, Timothy C., Patel, Aman R., Scott, June R.

The important human pathogen Streptococcus pyogenes (group A streptococcus GAS), requires several surface proteins to interact with its human host. Many of these are covalently linked by a sortase...

The pCoo Plasmid of Enterotoxigenic Escherichia coli Is a Mosaic Cointegrate†

Froehlich, Barbara, Parkhill, Julian, Sanders, Mandy, Quail, Michael A., Scott, June R.

CS1 is the prototype of a class of pili of enterotoxigenic Escherichia coli (ETEC) associated with diarrheal disease in humans. The genes encoding this pilus are carried on a large plasmid, pCoo. We...

Assembly of CS1 Pili: the Role of Specific Residues of the Major Pilin, CooA

Starks, Angela M., Froehlich, Barbara J., Jones, Tamara N., Scott, June R.

CS1 pili are important virulence factors of enterotoxigenic Escherichia coli strains associated with human diarrheal disease. They are the prototype for a family of pili that share extensive sequence...

RscA, a Member of the MDR1 Family of Transporters, Is Repressed by CovR and Required for Growth of Streptococcus pyogenes under Heat Stress†

Dalton, Tracy L., Collins, Julie T., Barnett, Timothy C., Scott, June R.

The ability of Streptococcus pyogenes (group A streptococcus [GAS]) to respond to changes in environmental conditions is essential for this gram-positive organism to successfully cause disease in its...

Phosphorylation of the Group A Streptococcal CovR Response Regulator Causes Dimerization and Promoter-Specific Recruitment by RNA Polymerase

Gusa, Asiya A., Gao, Jinxin, Stringer, Virginia, Churchward, Gordon, Scott, June R.

The group A streptococcus (GAS), Streptococcus pyogenes, is an important human pathogen that causes infections ranging in severity from self-limiting pharyngitis to severe invasive diseases that are...

A conserved residue in the tip proteins of CS1 and CFA/I pili of enterotoxigenic Escherichia coli that is essential for adherence

Sakellaris, Harry, Munson, George P., Scott, June R.

Enterotoxigenic Escherichia coli associated with human diarrheal disease utilize any of a limited group of serologically distinguishable pili for attachment to intestinal cells. These include CS1 and...

CooB plays a chaperone-like role for the proteins involved in formation of CS1 pili of enterotoxigenic Escherichia coli

Voegele, Karl, Sakellaris, Harry, Scott, June R.

CS1 pili serve as the prototype of a class of filamentous appendages found on the surface of strains of enterotoxigenic Escherichia coli. The four genes needed to synthesize functional CS1 pili in E....

Excision of the Conjugative Transposon Tn916 in Lactococcus lactis

Marra, Diana, Smith, Jennifer G., Scott, June R.

In Lactococcus lactis excision of Tn916 is limited by the concentration of integrase and is increased by providing more excisionase. However, even with increased excision of Tn916 in L. lactis, no...

The Level of Expression of the Minor Pilin Subunit, CooD, Determines the Number of CS1 Pili Assembled on the Cell Surface of Escherichia coli

Sakellaris, Harry, Penumalli, Vikram R., Scott, June R.

CooD, the minor subunit of CS1 pili of enterotoxigenic Escherichia coli, is essential for the assembly of stable, functional pili. We previously proposed that CooD is a rate-limiting initiator of CS1...

Binding Site Recognition by Rns, a Virulence Regulator in the AraC Family

Munson, George P., Scott, June R.

The expression of CS1 pili by enterotoxigenic strains of Escherichia coli is regulated at the transcriptional level and requires the virulence regulator Rns, a member of the AraC family of regulatory...

A Response Regulator That Represses Transcription of Several Virulence Operons in the Group A Streptococcus

Federle, Michael J., McIver, Kevin S., Scott, June R.

A search for homologs of the Bacillus subtilis PhoP response regulator in the group A streptococcus (GAS) genome revealed three good candidates. Inactivation of one of these, recently identified as...

Regulation of mga Transcription in the Group A Streptococcus: Specific Binding of Mga within Its Own Promoter and Evidence for a Negative Regulator

McIver, Kevin S., Thurman, Alec S., Scott, June R.

Transcription of mga, encoding the multiple virulence gene regulator of the group A streptococcus, is positively autoregulated. This regulation requires a DNA region (Pmga) that contains both a...

The Frequency of Conjugative Transposition of Tn916 Is Not Determined by the Frequency of Excision

Marra, Diana, Pethel, Beth, Churchward, Gordon G., Scott, June R.

Excision and formation of a covalently closed circular transposon molecule are required for conjugative transposition of Tn916 but are not the only factors that limit the frequency of conjugative...

Attenuated Expression of the mga Virulence Regulon in an M Serotype 50 Mouse-Virulent Group A Streptococcal Strain

Yung, Der-Li, McIver, Kevin S., Scott, June R., Hollingshead, Susan K.

The attenuated expression of virulence genes found in a group A streptococcal strain that is naturally pathogenic for mice was postulated to result from a defect in the strain's multigene regulator,...

Role of Streptolysin O in a Mouse Model of Invasive Group A Streptococcal Disease

Limbago, Brandi, Penumalli, Vikram, Weinrick, Brian, Scott, June R.

Many of the virulence factors that have been characterized for group A streptococci (GAS) are not expressed in all clinical isolates. One putative virulence factor that is present among most is...

Novel Group of Virulence Activators within the AraC Family That Are Not Restricted to Upstream Binding Sites

Munson, George P., Holcomb, Lisa G., Scott, June R.

Several regulators within the AraC family control the expression of genes known or thought to be required for virulence of bacterial pathogens. One of these, Rns, activates transcription from an...

Restoration of Mga Function to a Streptococcus pyogenes Strain (M Type 50) That Is Virulent in Mice

Limbago, Brandi, McIver, Kevin S., Penumalli, Vikram, Weinrick, Brian, Scott, June R.

The Mga protein in B514Sm, a Streptococcus pyogenes strain isolated as a mouse pathogen, contains amino acid substitutions at conserved sites that render the protein defective. Replacement of mga50...

Generation and Surface Localization of Intact M Protein in Streptococcus pyogenes Are Dependent on sagA

Biswas, Indranil, Germon, Pierre, McDade, Kathleen, Scott, June R.

The M protein is an important surface-located virulence factor of Streptococcus pyogenes, the group A streptococcus (GAS). Expression of M protein is primarily controlled by Mga, a transcriptional...

Use of the Lactococcal nisA Promoter To Regulate Gene Expression in Gram-Positive Bacteria: Comparison of Induction Level and Promoter Strength

Eichenbaum, Zehava, Federle, Michael J., Marra, Diana, De Vos, Willem M., Kuipers, Oscar P., Kleerebezem, Michiel, ...

We characterized the regulated activity of the lactococcal nisA promoter in strains of the gram-positive species Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae,...

Virulence control in group A Streptococcus by a two-component gene regulatory system: Global expression profiling and in vivo infection modeling

Graham, Morag R., Smoot, Laura M., Migliaccio, Cristi A. Lux, Virtaneva, Kimmo, Sturdevant, Daniel E., Porcella, Stephen F., ...

Two-component gene regulatory systems composed of a membrane-bound sensor and cytoplasmic response regulator are important mechanisms used by bacteria to sense and respond to environmental stimuli....

In Vitro Identification of Rns-Regulated Genes

Munson, George P., Holcomb, Lisa G., Alexander, Heather L., Scott, June R.

To identify Rns-regulated genes, a maltose binding protein (MBP)-Rns fusion protein was used to isolate DNA fragments from enterotoxigenic Escherichia coli genomic DNA that carry Rns binding sites....

Differential Recognition of Surface Proteins in Streptococcus pyogenes by Two Sortase Gene Homologs

Barnett, Timothy C., Scott, June R.

The interaction of Streptococcus pyogenes (group A streptococcus [GAS]) with its human host requires several surface proteins. In this study, we isolated mutations in a gene required for the surface...

Identification of rocA, a Positive Regulator of covR Expression in the Group A Streptococcus

Biswas, Indranil, Scott, June R.

In the group A streptococcus (GAS; Streptococcus pyogenes), a two-component system known as CovRS (or CsrRS) regulates about 15% of the genes, including several important virulence factors like the...

Expression of the Secondary Sigma Factor σX in Streptococcus pyogenes Is Restricted at Two Levels

Opdyke, Jason A., Scott, June R.

Secondary RNA polymerase sigma factors in many bacteria are responsible for regulating a vast range of processes including virulence. A protein (σX) in the gram-positive human pathogen Streptococcus...

Mutants of Plasmid Prophage P1 with Elevated Copy Number: Isolation and Characterization

Scott, June R., Kropf, Martha M., Padolsky, Linda, Goodspeed, James K., Davis, Richard, Vapnek, Daniel

A series of mutations of the P1 plasmid prophage that lead to increased copy number was isolated and analyzed. The copy number of the mutants was elevated at least five- to eightfold relative to...

Horizontal Transfer of CS1 Pilin Genes of Enterotoxigenic Escherichia coli

Froehlich, Barbara, Holtzapple, Erik, Read, Timothy D., Scott, June R.

CS1 is one of a limited number of serologically distinct pili found in enterotoxigenic Escherichia coli (ETEC) strains associated with disease in people. The genes for the CS1 pilus are on a large...

CovS Inactivates CovR and Is Required for Growth under Conditions of General Stress in Streptococcus pyogenes

Dalton, Tracy L., Scott, June R.

The gram-positive human pathogen Streptococcus pyogenes (group A streptococcus [GAS]) causes diseases ranging from mild and often self-limiting infections of the skin or throat to invasive and...

A Novel Sortase, SrtC2, from Streptococcus pyogenes Anchors a Surface Protein Containing a QVPTGV Motif to the Cell Wall

Barnett, Timothy C., Patel, Aman R., Scott, June R.

The important human pathogen Streptococcus pyogenes (group A streptococcus GAS), requires several surface proteins to interact with its human host. Many of these are covalently linked by a sortase...

The pCoo Plasmid of Enterotoxigenic Escherichia coli Is a Mosaic Cointegrate†

Froehlich, Barbara, Parkhill, Julian, Sanders, Mandy, Quail, Michael A., Scott, June R.

CS1 is the prototype of a class of pili of enterotoxigenic Escherichia coli (ETEC) associated with diarrheal disease in humans. The genes encoding this pilus are carried on a large plasmid, pCoo. We...

Assembly of CS1 Pili: the Role of Specific Residues of the Major Pilin, CooA

Starks, Angela M., Froehlich, Barbara J., Jones, Tamara N., Scott, June R.

CS1 pili are important virulence factors of enterotoxigenic Escherichia coli strains associated with human diarrheal disease. They are the prototype for a family of pili that share extensive sequence...

RscA, a Member of the MDR1 Family of Transporters, Is Repressed by CovR and Required for Growth of Streptococcus pyogenes under Heat Stress†

Dalton, Tracy L., Collins, Julie T., Barnett, Timothy C., Scott, June R.

The ability of Streptococcus pyogenes (group A streptococcus [GAS]) to respond to changes in environmental conditions is essential for this gram-positive organism to successfully cause disease in its...

Phosphorylation of the Group A Streptococcal CovR Response Regulator Causes Dimerization and Promoter-Specific Recruitment by RNA Polymerase

Gusa, Asiya A., Gao, Jinxin, Stringer, Virginia, Churchward, Gordon, Scott, June R.

The group A streptococcus (GAS), Streptococcus pyogenes, is an important human pathogen that causes infections ranging in severity from self-limiting pharyngitis to severe invasive diseases that are...

CovR Activation of the Dipeptide Permease Promoter (PdppA) in Group A Streptococcus▿

Gusa, Asiya A., Froehlich, Barbara J., Desai, Devak, Stringer, Virginia, Scott, June R.

CovR, the two-component response regulator of Streptococcus pyogenes (group A streptococcus [GAS]) directly or indirectly represses about 15% of the genome, including genes encoding many virulence...

Unraveling the Regulatory Network in Streptococcus pyogenes: the Global Response Regulator CovR Represses rivR Directly▿

Roberts, Samantha A., Churchward, Gordon G., Scott, June R.

The response regulator CovR acts as a master regulator of virulence in Streptococcus pyogenes by repressing transcription of approximately 15% of the group A streptococcus genome directly or...

Role of mRNA Stability in Growth Phase Regulation of Gene Expression in the Group A Streptococcus▿ †

Barnett, Timothy C., Bugrysheva, Julia V., Scott, June R.

The impressive disease spectrum of Streptococcus pyogenes (the group A streptococcus [GAS]) is believed to be determined by its ability to modify gene expression in response to environmental stimuli....

SipA Is Required for Pilus Formation in Streptococcus pyogenes Serotype M3▿

Zähner, Dorothea, Scott, June R.

Pili are a major surface feature of the human pathogen Streptococcus pyogenes (group A streptococcus [GAS]). The T3 pilus is composed of a covalently linked polymer of protein T3 (formerly Orf100 or...

TrxR, a New CovR-Repressed Response Regulator That Activates the Mga Virulence Regulon in Group A Streptococcus▿ †

Leday, Temekka V., Gold, Kathryn M., Kinkel, Traci L., Roberts, Samantha A., Scott, June R., McIver, Kevin S.

Coordinate regulation of virulence factors by the group A streptococcus (GAS) Streptococcus pyogenes is important in this pathogen's ability to cause disease. To further elucidate the regulatory...

Streptococcus pyogenes CovRS Mediates Growth in Iron Starvation and in the Presence of the Human Cationic Antimicrobial Peptide LL-37 ▿

Froehlich, Barbara J., Bates, Christopher, Scott, June R.

We found that the global regulatory two-component signal transduction system CovRS mediates the ability of group A streptococcus (GAS) to grow under two stresses encountered during infection: iron...