scholarly journals Genetic Analysis of the Enterococcus Vancomycin Resistance Conjugative Plasmid pHTβ: Identification of the Region Involved in Cell Aggregation and traB, a Key Regulator Gene for Plasmid Transfer and Cell Aggregation

2008 ◽  
Vol 190 (23) ◽  
pp. 7739-7753 ◽  
Author(s):  
Haruyoshi Tomita ◽  
Yasuyoshi Ike
Keyword(s):  
Deletion Mutant ◽  
Cell Aggregation ◽  
Vancomycin Resistance ◽  
Plasmid Transfer ◽  
Open Reading Frames ◽  
Conjugative Plasmid ◽  
Host Strain ◽  
Transcription Analysis ◽  
Transfer Frequency ◽  
Reading Frames

ABSTRACT The Enterococcus plasmid pHTβ (63.7 kbp) is a pheromone-independent, highly conjugative pMG1-like plasmid that carries a Tn1546-like transposon encoding vancomycin resistance. The transfer-related regions (Tra I, Tra II, and Tra III) containing oriT and a putative nickase gene (traI) have previously been identified in pHTβ, and in this study, we found that the plasmid conferred the ability to self-aggregate on the host strain Enterococcus faecalis FA2-2. A region where mutation resulted in the impairment of aggregation was identified and mapped to a point upstream of the transfer-related Tra I region. This region consisted of an approximately 6-kbp segment that contained the five open reading frames (ORFs) ORF9 to ORF13. These ORFs are considered to encode the aggregation function, although the precise mode of action of each ORF has not yet been elucidated. An in-frame deletion mutant of ORF10 resulted in reduced aggregation and decreased transfer frequency in broth mating. Transcription analysis of the aggregation region showed that the five ORFs from ORF9 to ORF13 form an operon structure, and a long transcript that started from a promoter region located upstream of ORF9 was identified. Tra II spans a 1.7-kbp region containing ORF56 and ORF57. Tn917-lac insertions into or an in-frame deletion mutant of ORF56 (187 amino acids) resulted in impaired transfer and aggregation. The cloned ORF56 complemented these functions in trans. The transcription levels of ORF10 and ORF13 were reduced in the in-frame mutants of ORF56, but this reduction was complemented by a cloned ORF56 in trans. The results indicated that ORF56 positively regulated the aggregation and plasmid transfer in the host strain, and ORF56 was designated traB.

scholarly journals Complete Nucleotide Sequence of Plasmid Rts1: Implications for Evolution of Large Plasmid Genomes

2002 ◽  
Vol 184 (12) ◽  
pp. 3194-3202 ◽  
Author(s):  
Takahiro Murata ◽  
Makoto Ohnishi ◽  
Takeshi Ara ◽  
Jun Kaneko ◽  
Chang-Gyun Han ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Complete Nucleotide Sequence ◽  
Sequence Similarity ◽  
Open Reading Frames ◽  
Conjugative Plasmid ◽  
Proteus Vulgaris ◽  
Significant Sequence Similarity ◽  
Modular Evolution ◽  
Broad Array ◽  
Reading Frames

ABSTRACT Rts1, a large conjugative plasmid originally isolated from Proteus vulgaris, is a prototype for the IncT plasmids and exhibits pleiotropic thermosensitive phenotypes. Here we report the complete nucleotide sequence of Rts1. The genome is 217,182 bp in length and contains 300 potential open reading frames (ORFs). Among these, the products of 141 ORFs, including 9 previously identified genes, displayed significant sequence similarity to known proteins. The set of genes responsible for the conjugation function of Rts1 has been identified. A broad array of genes related to diverse processes of DNA metabolism were also identified. Of particular interest was the presence of tus-like genes that could be involved in replication termination. Inspection of the overall genome organization revealed that the Rts1 genome is composed of four large modules, providing an example of modular evolution of plasmid genomes.

scholarly journals Chromosomal Arm Replacement in Streptomyces griseus

2003 ◽  
Vol 185 (3) ◽  
pp. 1120-1124 ◽  
Author(s):  
Tetsuya Uchida ◽  
Mariko Miyawaki ◽  
Haruyasu Kinashi
Keyword(s):  
Dna Repair ◽  
Deletion Mutant ◽  
Streptomyces Griseus ◽  
Open Reading Frames ◽  
Inverted Repeats ◽  
Sequencing Analysis ◽  
Chromosomal Deletion ◽  
Terminal Inverted Repeats ◽  
Left And Right ◽  
Reading Frames

ABSTRACT UV irradiation of Streptomyces griseus 2247 yielded a new chromosomal deletion mutant, MM9. Restriction and sequencing analysis revealed that homologous recombination between two similar lipoprotein-like open reading frames, which are located 450 and 250 kb from the left and right ends, respectively, caused chromosomal arm replacement. As a result, new 450-kb terminal inverted repeats (TIRs) were formed in place of the original 24-kb TIRs. Frequent homologous recombinations in Streptomyces strains suggest that telomere deletions can usually be repaired by recombinational DNA repair functioning between the intact and deleted TIR sequences on the same chromosome.

scholarly journals Regulation of transcription by Saccharomyces cerevisiae 14-3-3 proteins

2004 ◽  
Vol 382 (3) ◽  
pp. 867-875 ◽  
Author(s):  
Astrid BRUCKMANN ◽  
H. Yde STEENSMA ◽  
M. Joost TEIXEIRA de MATTOS ◽  
G. Paul H. van HEUSDEN
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Response ◽  
Open Reading Frames ◽  
Ergosterol Biosynthesis ◽  
Temperature Sensitive ◽  
Regulation Of Transcription ◽  
Mrna Levels ◽  
Transcription Analysis ◽  
A Genome ◽  
Reading Frames

14-3-3 proteins form a family of highly conserved eukaryotic proteins involved in a wide variety of cellular processes, including signalling, apoptosis, cell-cycle control and transcriptional regulation. More than 150 binding partners have been found for these proteins. The yeast Saccharomyces cerevisiae has two genes encoding 14-3-3 proteins, BMH1 and BMH2. A bmh1 bmh2 double mutant is unviable in most laboratory strains. Previously, we constructed a temperature-sensitive bmh2 mutant and showed that mutations in RTG3 and SIN4, both encoding transcriptional regulators, can suppress the temperature-sensitive phenotype of this mutant, suggesting an inhibitory role of the 14-3-3 proteins in Rtg3-dependent transcription [van Heusden and Steensma (2001) Yeast 18, 1479–1491]. In the present paper, we report a genome-wide transcription analysis of a temperature-sensitive bmh2 mutant. Steady-state mRNA levels of 60 open reading frames were increased more than 2.0-fold in the bmh2 mutant, whereas those of 78 open reading frames were decreased more than 2.0-fold. In agreement with our genetic experiments, six genes known to be regulated by Rtg3 showed elevated mRNA levels in the mutant. In addition, several genes with other cellular functions, including those involved in gluconeogenesis, ergosterol biosynthesis and stress response, had altered mRNA levels in the mutant. Our data show that the yeast 14-3-3 proteins negatively regulate Rtg3-dependent transcription, stimulate the transcription of genes involved in ergosterol metabolism and in stress response and are involved in transcription regulation of multiple other genes.

scholarly journals Cloning and Genetic Analyses of the Bacteriocin 41 Determinant Encoded on the Enterococcus faecalis Pheromone-Responsive Conjugative Plasmid pYI14: a Novel Bacteriocin Complemented by Two Extracellular Components (Lysin and Activator)

2008 ◽  
Vol 190 (6) ◽  
pp. 2075-2085 ◽  
Author(s):  
Haruyoshi Tomita ◽  
Elizabeth Kamei ◽  
Yasuyoshi Ike
Keyword(s):  
Enterococcus Faecalis ◽  
Sequence Data ◽  
Open Reading Frames ◽  
Conjugative Plasmid ◽  
Cell Surface Receptor ◽  
Bacteriocin Activity ◽  
Lytic Enzymes ◽  
Repeat Structure ◽  
Surface Receptor ◽  
Reading Frames

ABSTRACT The conjugative plasmid pYI14 (61 kbp) was isolated from Enterococcus faecalis YI714, a clinical isolate. pYI14 conferred a pheromone response on its host and encoded bacteriocin 41 (bac41). Bacteriocin 41 (Bac41) only showed activity against E. faecalis. Physical mapping of pYI14 showed that it consisted of EcoRI fragments A to P. The clone pHT1100, containing EcoRI fragments A (12.6 kbp) and H (3.5 kbp), conferred the bacteriocin activity on E. faecalis strains. Genetic analysis showed that the determinant was located in a 6.6-kbp region within the EcoRI AH fragments. Six open reading frames (ORFs) were identified in this region and designated ORF7 (bacL1 ) ORF8 (bacL2 ), ORF9, ORF10, ORF11 (bacA), and ORF12 (bacI). They were aligned in this order and oriented in the same direction. ORFs bacL1 , bacL2 , bacA, and bacI were essential for expression of the bacteriocin in E. faecalis. Extracellular complementation of bacteriocin expression was possible for bacL1 and -L2 and bacA mutants. bacL1 and -L2 and bacA encoded bacteriocin component L and activator component A, respectively. The products of these genes are secreted into the culture medium and extracellularly complement bacteriocin expression. bacI encoded immunity, providing the host with resistance to its own bacteriocin activity. The bacL1 -encoded protein had significant homology with lytic enzymes that attack the gram-positive bacterial cell wall. Sequence data for the deduced bacL1 -encoded protein suggested that it has a domain structure consisting of an N-terminal signal peptide, a second domain with the enzymatic activity, and a third domain with a three-repeat structure directing the proenzyme to its cell surface receptor.

scholarly journals Genetic Analysis of the AdnA Regulon in Pseudomonas fluorescens: Nonessential Role of Flagella in Adhesion to Sand and Biofilm Formation

2003 ◽  
Vol 185 (2) ◽  
pp. 453-460 ◽  
Author(s):  
Eduardo A. Robleto ◽  
Inmaculada López-Hernández ◽  
Mark W. Silby ◽  
Stuart B. Levy
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Transcription Factor ◽  
Pseudomonas Fluorescens ◽  
Biofilm Formation ◽  
Deletion Mutant ◽  
Open Reading Frames ◽  
Cell Processes ◽  
Reading Frames ◽  
Insertion Mutants

ABSTRACT AdnA is a transcription factor in Pseudomonas fluorescens that affects flagellar synthesis, biofilm formation, and sand adhesion. To identify the AdnA regulon, we used a promoterless Tn5-lacZ element to study the phenotypes of insertion mutants in the presence and absence of AdnA. Of 12,000 insertions, we identified seven different putative open reading frames (ORFs) activated by AdnA (named aba for activated by AdnA). aba120 and aba177 showed homology to flgC and flgI, components of the basal body of the flagella in Pseudomonas aeruginosa. Two other insertions, aba18 and aba51, disrupted genes affecting chemotaxis. The mutant loci aba160 (possibly affecting lipopolysaccharide synthesis) and aba175 (unknown function) led to loss of flagella. The mutant bearing aba203 became motile when complemented with adnA, but the mutated gene showed no similarity to known genes. Curiously, aba18, aba51, aba160, and aba203 mutants formed biofilms even in the absence of AdnA, suppressing the phenotype of the adnA deletion mutant. The combined findings suggest that flagella are nonessential for sand attachment or biofilm formation. Sequence and promoter analyses indicate that AdnA affects at least 23 ORFs either directly or by polar effects. These results support the concept that AdnA regulates cell processes other than those directly related to flagellar synthesis and define a broader cadre of genes in P. fluorescens than that described so far for its homolog, FleQ, in P. aeruginosa.

scholarly journals Genetic Analysis of Transfer-Related Regions of the Vancomycin Resistance Enterococcus Conjugative Plasmid pHTβ: Identification of oriT and a Putative Relaxase Gene

2005 ◽  
Vol 187 (22) ◽  
pp. 7727-7737 ◽  
Author(s):  
Haruyoshi Tomita ◽  
Yasuyoshi Ike
Keyword(s):  
Direct Repeat ◽  
Vancomycin Resistance ◽  
Conjugative Plasmid ◽  
Homology Search ◽  
Virulence Plasmid ◽  
Lacz Expression ◽  
Significant Similarity ◽  
Transfer Frequency ◽  
Repeat Sequences ◽  
Insertion Mutants

ABSTRACT The pHT plasmids pHTα (65.9 kbp), pHTβ (63.7 kbp), and pHTγ (66.5 kbp) are highly conjugative pheromone-independent pMG1-like plasmids that carry Tn1546-like transposons encoding vancomycin resistance. pHTβ is the prototype plasmid, and the pHTα and pHTγ plasmids are derivatives of the insertion into pHTβ of an IS232-like (2.2 kbp) element and a group II intron (2.8 kbp), respectively. The complete nucleotide sequence of the pHTβ plasmid was determined and, with the exception of the Tn1546-like insertion (10,851 bp), was found to be 52,890 bp. Sixty-one open reading frames (ORFs) having the same transcript orientation were identified. A homology search revealed that 22 of the pHTβ (pHT) plasmid ORFs showed similarities to the ORFs identified on the pXO2 plasmid (96.2 kbp), which is the virulence plasmid essential for capsule formation by Bacillus anthracis; however, the functions of most of the ORFs remain unknown. Most other ORFs did not show any significant homology to reported genes for which functions have been analyzed. To investigate the highly efficient transfer mechanism of the pHT plasmid, mutations with 174 unique insertions of transposon Tn917-lac insertion mutants of pHTβ were obtained. Of the 174 derivatives, 92 showed decrease or loss in transfer frequency, and 74 showed normal transfer frequency and LacZ expression. Eight derivatives showed normal transfer and no LacZ expression. Inserts within the 174 derivatives were mapped to 124 different sites on pHTβ. The Tn917-lac insertions which resulted in altered transfer frequency mapped to three separate regions designated I, II, and III, which were separated by segments in which insertions of Tn917-lac did not affect transfer. There was no region homologous to the previously reported oriT sequences in the pHT plasmid. The oriT was cloned by selection for the ability to mobilize the vector plasmid pAM401. The oriT region resided in a noncoding region (192 bp) between ORF31 and ORF32 and contained three direct repeat sequences and two inverted repeat sequences. ORF34, encoding a 506-amino-acid protein which was located downstream of the oriT region, contains the three conserved motifs (I to III) of the DNA relaxase/nickase of mobile plasmids. The transfer abilities of the Tn917-lac-insertion mutants of ORF34 or a mutant of ORF34 with an in-frame motif III deletion were completely abolished. The sequence of the oriT region and the deduced relaxase/nickase protein of ORF34 showed no significant similarity to the oriT and relaxase/nickase of other conjugative plasmids, respectively. The putative relaxase/nickase protein of ORF34 could be classified as a new member of the MOBMG family.

scholarly journals Genetic Characterization of vanG, a Novel Vancomycin Resistance Locus of Enterococcus faecalis

2000 ◽  
Vol 44 (11) ◽  
pp. 3224-3228 ◽  
Author(s):  
Stuart J. McKessar ◽  
Anne M. Berry ◽  
Jan M. Bell ◽  
John D. Turnidge ◽  
James C. Paton
Keyword(s):  
Enterococcus Faecalis ◽  
Amino Acid Sequence Identity ◽  
Vancomycin Resistance ◽  
Open Reading Frames ◽  
Pcr Analysis ◽  
Resistance Locus ◽  
Gene Products ◽  
The Individual ◽  
Reading Frames

ABSTRACT Enterococcus faecalis strain WCH9 displays a moderate level of resistance to vancomycin (MIC = 16 μg/ml) and full susceptibility to teicoplanin but is negative by PCR analysis using primers specific for all known enterococcal vancomycin resistance genotypes (vanA, vanB,vanC, vanD, and vanE). We have isolated and sequenced a novel putative vancomycin resistance locus (designated vanG), which contains seven open reading frames, from this strain. These are organized differently from those of all the other enterococcal vanloci, and, furthermore, the individual vanG gene products exhibit less than 50% amino acid sequence identity to othervan gene products.

scholarly journals Transcription Analysis of the Bacillus subtilis PucR Regulon and Identification of a cis-Acting Sequence Required for PucR-Regulated Expression of Genes Involved in Purine Catabolism

2002 ◽  
Vol 184 (12) ◽  
pp. 3232-3241 ◽  
Author(s):  
Lars Beier ◽  
Per Nygaard ◽  
Hanne Jarmer ◽  
Hans H. Saxild
Keyword(s):  
Bacillus Subtilis ◽  
Regulatory Protein ◽  
Bioinformatic Analysis ◽  
Open Reading Frames ◽  
Negative Regulator ◽  
Gram Positive ◽  
Transcription Analysis ◽  
Purine Catabolism ◽  
Gram Positive Bacteria ◽  
Reading Frames

ABSTRACT The PucR protein of Bacillus subtilis has previously been suggested to regulate the expression of 15 genes, pucABCDE, pucFG, pucH, pucI, pucJKLM, pucR, and gde, all of which encode proteins involved in purine catabolism. When cells are grown under nitrogen-limiting conditions, the expression of these genes is induced and intermediary compounds of the purine catabolic pathway affect this expression. By using pucR deletion mutants, we have found that PucR induces the expression of pucFG, pucH, pucI, pucJKLM, and gde while it represses the expression of pucR and pucABCDE. Deletions in the promoters of the five induced operons and genes combined with bioinformatic analysis suggested a conserved upstream activating sequence, 5′-WWWCNTTGGTTAA-3′, now named the PucR box. Potential PucR boxes overlapping the −35 and −10 regions of the pucABCDE promoter and located downstream of the pucR transcription start point were also found. The positions of these PucR boxes are consistent with PucR acting as a negative regulator of pucABCDE and pucR expression. Site-directed mutations in the PucR box upstream of pucH and pucI identified positions that are essential for the induction of pucH and pucI expression, respectively. Mutants with decreased pucH or increased pucR expression obtained from a library of clones containing random mutations in the pucH-to-pucR intercistronic region all contained mutations in or near the PucR box. The induction of pucR expression under nitrogen-limiting conditions was found to be mediated by the global nitrogen-regulatory protein TnrA. In other gram-positive bacteria, we have found open reading frames that encode proteins similar to PucR located next to other open reading frames encoding proteins with similarity to purine catabolic enzymes. Hence, the PucR homologues are likely to exert the same function in other gram-positive bacteria as PucR does in B. subtilis.

scholarly journals Isolation of VanB-Type Enterococcus faecalis Strains from Nosocomial Infections: First Report of the Isolation and Identification of the Pheromone-Responsive Plasmids pMG2200, Encoding VanB-Type Vancomycin Resistance and a Bac41-Type Bacteriocin, and pMG2201, Encoding Erythromycin Resistance and Cytolysin (Hly/Bac)

2008 ◽  
Vol 53 (2) ◽  
pp. 735-747 ◽  
Author(s):  
Bo Zheng ◽  
Haruyoshi Tomita ◽  
Takako Inoue ◽  
Yasuyoshi Ike
Keyword(s):  
Enterococcus Faecalis ◽  
Regulatory Region ◽  
Vancomycin Resistance ◽  
Conjugative Plasmid ◽  
Host Strain ◽  
Erythromycin Resistance ◽  
Isolation And Identification ◽  
First Report ◽  
Isolation And Characterization ◽  
Synthetic Pheromone

ABSTRACT Eighteen identical VanB-type Enterococcus faecalis isolates that were obtained from different hospitalized patients were examined for their drug resistance and plasmid DNAs. Of the 18 strains, 12 strains exhibited resistance to erythromycin (Em), gentamicin (Gm), kanamycin (Km), tetracycline (Tc), and vancomycin (Van) and produced cytolysin (Hly/Bac) and a bacteriocin (Bac) active against E. faecalis strains. Another six of the strains exhibited resistance to Gm, Km, Tc, and Van and produced a bacteriocin. Em and Van resistance was transferred individually to E. faecalis FA2-2 strains at a frequency of about 10−4 per donor cell by broth mating. The Em-resistant transconjugants and the Van-resistant transconjugants harbored a 65.7-kbp plasmid and a 106-kbp plasmid, respectively. The 106-kbp and 65.7-kbp plasmids isolated from the representative E. faecalis NKH15 strains were designated pMG2200 and pMG2201, respectively. pMG2200 conferred vancomycin resistance and bacteriocin activity on the host strain and responded to the synthetic pheromone cCF10 for pCF10, while pMG2201 conferred erythromycin resistance and cytolysin activity on its host strain and responded to the synthetic pheromone cAD1 for pAD1. The complete DNA sequence of pMG2200 (106,527 bp) showed that the plasmid carried a Tn1549-like element encoding vanB2-type resistance and the Bac41-like bacteriocin genes of pheromone-responsive plasmid pYI14. The plasmid contained the regulatory region found in pheromone-responsive plasmids and encoded the genes prgX and prgQ, which are the key negative regulatory elements for plasmid pCF10. pMG2200 also encoded TraE1, a key positive regulator of plasmid pAD1, indicating that pMG2200 is a naturally occurring chimeric plasmid that has a resulting prgX-prgQ-traE1 genetic organization in the regulatory region of the pheromone response. The functional oriT region and the putative relaxase gene of pMG2200 were identified and found to differ from those of pCF10 and pAD1. The putative relaxase of pMG2200 was classified as a member of the MOBMG family, which is found in pheromone-independent plasmid pHTβ of the pMG1-like plasmids. This is the first report of the isolation and characterization of a pheromone-responsive highly conjugative plasmid encoding vanB resistance.

scholarly journals Nucleotide Sequence and Analysis of Conjugative Plasmid pVT745

2001 ◽  
Vol 183 (5) ◽  
pp. 1585-1594 ◽  
Author(s):  
Dominique M. Galli ◽  
Jinbiao Chen ◽  
Karen F. Novak ◽  
Donald J. Leblanc
Keyword(s):  
Nucleotide Sequence ◽  
Open Reading Frames ◽  
Conjugative Plasmid ◽  
Periodontal Pathogen ◽  
Gene Products ◽  
E Coli ◽  
Replication Region ◽  
High Degree ◽  
Degree Of Similarity ◽  
Reading Frames

ABSTRACT The complete nucleotide sequence and genetic map of pVT745 are presented. The 25-kb plasmid was isolated from Actinobacillus actinomycetemcomitans, a periodontal pathogen. Two-thirds of the plasmid encode functions related to conjugation, replication, and replicon stability. Among potential gene products with a high degree of similarity to known proteins are those associated with plasmid conjugation. It was shown that pVT745 derivatives not only mobilized a coresident nontransmissible plasmid, pMMB67, but also mediated their own conjugative transfer to different A. actinomycetemcomitans strains. However, transfer of pVT745 derivatives from A. actinomycetemcomitansto Escherichia coli JM109 by conjugation was successful only when an E. coli origin of replication was present on the pVT745 construct. Surprisingly, 16 open reading frames encode products of unknown function. The plasmid contains a conserved replication region which belongs to the HAP (Haemophilus-Actinobacillus-Pasteurella) theta replicon family. However, its host range appears to be rather narrow compared to other members of this family. Sequences homologous to pVT745 have previously been detected in the chromosomes of numerousA. actinomycetemcomitans strains. The nature and origin of these homologs are discussed based on information derived from the nucleotide sequence.

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