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Identification and characterization of the chromosomal yefM-yoeB toxin-antitoxin system of Streptococcus suis.

Zheng C, Xu J, Ren S, Li J, Xia M, Chen H, Bei W - Sci Rep (2015)

Bottom Line: Overproduction of S. suis YoeB toxin inhibited the growth of E. coli, and the toxicity of S. suis YoeB could be alleviated by the antitoxin YefM from S. suis and Streptococcus pneumoniae, but not by E. coli YefM.In a murine infection model, deletion of the yefM-yoeB locus had no effect on the virulence of S. suis serotype 2.Collectively, our data suggested that the yefM-yoeB locus of S. suis is an active TA system without the involvement of virulence.

View Article: PubMed Central - PubMed

Affiliation: 1] State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, 430070, China [2] Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.

ABSTRACT
Toxin-antitoxin (TA) systems are widely prevalent in the genomes of bacteria and archaea. These modules have been identified in Escherichia coli and various other bacteria. However, their presence in the genome of Streptococcus suis, an important zoonotic pathogen, has received little attention. In this study, we describe the identification and characterization of a type II TA system, comprising the chromosomal yefM-yoeB locus of S. suis. The yefM-yoeB locus is present in the genome of most serotypes of S. suis. Overproduction of S. suis YoeB toxin inhibited the growth of E. coli, and the toxicity of S. suis YoeB could be alleviated by the antitoxin YefM from S. suis and Streptococcus pneumoniae, but not by E. coli YefM. More importantly, introduction of the S. suis yefM-yoeB system into E. coli could affect cell growth. In a murine infection model, deletion of the yefM-yoeB locus had no effect on the virulence of S. suis serotype 2. Collectively, our data suggested that the yefM-yoeB locus of S. suis is an active TA system without the involvement of virulence.

No MeSH data available.


Related in: MedlinePlus

The yefM-yoeB locus is organized as an operon.(a) Genetic organization of the yefM-yoeB locus in S. suis strain SC84. The putative −35 and −10 regions are boxed. The primers used for RT-PCR or PCR are drawn as arrows, and the expected sizes of the corresponding PCR products are shown below. (b) Co-transcription analysis. Total RNAs extracted from S. suis SC84 were used to synthesize cDNAs. PCR was carried out with primer pairs A1/A2, T1/T2 and A1/T2, respectively. Lanes 1, 4 and 7 represent the amplification using cDNAs as the template; Lanes 2, 5 and 8 represent the amplification using genomic DNA (gDNA) as the template; Lanes 3, 6 and 9 represent the amplification using cDNA- (cDNA reaction without reverse transcriptase) as the template. The DL 2000 DNA Marker is shown on the left (lane M).
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f2: The yefM-yoeB locus is organized as an operon.(a) Genetic organization of the yefM-yoeB locus in S. suis strain SC84. The putative −35 and −10 regions are boxed. The primers used for RT-PCR or PCR are drawn as arrows, and the expected sizes of the corresponding PCR products are shown below. (b) Co-transcription analysis. Total RNAs extracted from S. suis SC84 were used to synthesize cDNAs. PCR was carried out with primer pairs A1/A2, T1/T2 and A1/T2, respectively. Lanes 1, 4 and 7 represent the amplification using cDNAs as the template; Lanes 2, 5 and 8 represent the amplification using genomic DNA (gDNA) as the template; Lanes 3, 6 and 9 represent the amplification using cDNA- (cDNA reaction without reverse transcriptase) as the template. The DL 2000 DNA Marker is shown on the left (lane M).

Mentions: A genetic structure analysis revealed that yefM is located upstream of yoeB, and the two genes are separated by one nucleotide, apparently arranged in a bicistronic operon (Fig. 2a). BPROM analysis of the upstream region of the yefM gene (about 300 bp) identified the putative −35 and −10 regions, which are located in the intergenic region between the yefM gene and its upstream gene (Fig. 2a). To assess whether yefM and yoeB are co-transcribed in S. suis, a reverse transcription polymerase chain reaction (RT-PCR) analysis was performed. Reverse transcriptase was used to synthesize cDNAs and the resulting cDNAs were PCR amplified using primer pair A1/T2. The individual yefM and yoeB genes were also amplified using primer pairs A1/A2 and T1/T2, respectively. As shown in Fig. 2b, the PCR products were of the expected sizes for yefM (261 bp), yoeB (258 bp) and yefM-yoeB (520 bp), all consistent with that of the genomic DNA. No PCR products were evident in the negative controls, in which the reverse transcription was performed without the enzyme, therefore eliminating possible DNA contamination. These results demonstrated that in S. suis, yefM and yoeB are actively co-transcribed, thus forming a bicistronic operon.


Identification and characterization of the chromosomal yefM-yoeB toxin-antitoxin system of Streptococcus suis.

Zheng C, Xu J, Ren S, Li J, Xia M, Chen H, Bei W - Sci Rep (2015)

The yefM-yoeB locus is organized as an operon.(a) Genetic organization of the yefM-yoeB locus in S. suis strain SC84. The putative −35 and −10 regions are boxed. The primers used for RT-PCR or PCR are drawn as arrows, and the expected sizes of the corresponding PCR products are shown below. (b) Co-transcription analysis. Total RNAs extracted from S. suis SC84 were used to synthesize cDNAs. PCR was carried out with primer pairs A1/A2, T1/T2 and A1/T2, respectively. Lanes 1, 4 and 7 represent the amplification using cDNAs as the template; Lanes 2, 5 and 8 represent the amplification using genomic DNA (gDNA) as the template; Lanes 3, 6 and 9 represent the amplification using cDNA- (cDNA reaction without reverse transcriptase) as the template. The DL 2000 DNA Marker is shown on the left (lane M).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4536659&req=5

f2: The yefM-yoeB locus is organized as an operon.(a) Genetic organization of the yefM-yoeB locus in S. suis strain SC84. The putative −35 and −10 regions are boxed. The primers used for RT-PCR or PCR are drawn as arrows, and the expected sizes of the corresponding PCR products are shown below. (b) Co-transcription analysis. Total RNAs extracted from S. suis SC84 were used to synthesize cDNAs. PCR was carried out with primer pairs A1/A2, T1/T2 and A1/T2, respectively. Lanes 1, 4 and 7 represent the amplification using cDNAs as the template; Lanes 2, 5 and 8 represent the amplification using genomic DNA (gDNA) as the template; Lanes 3, 6 and 9 represent the amplification using cDNA- (cDNA reaction without reverse transcriptase) as the template. The DL 2000 DNA Marker is shown on the left (lane M).
Mentions: A genetic structure analysis revealed that yefM is located upstream of yoeB, and the two genes are separated by one nucleotide, apparently arranged in a bicistronic operon (Fig. 2a). BPROM analysis of the upstream region of the yefM gene (about 300 bp) identified the putative −35 and −10 regions, which are located in the intergenic region between the yefM gene and its upstream gene (Fig. 2a). To assess whether yefM and yoeB are co-transcribed in S. suis, a reverse transcription polymerase chain reaction (RT-PCR) analysis was performed. Reverse transcriptase was used to synthesize cDNAs and the resulting cDNAs were PCR amplified using primer pair A1/T2. The individual yefM and yoeB genes were also amplified using primer pairs A1/A2 and T1/T2, respectively. As shown in Fig. 2b, the PCR products were of the expected sizes for yefM (261 bp), yoeB (258 bp) and yefM-yoeB (520 bp), all consistent with that of the genomic DNA. No PCR products were evident in the negative controls, in which the reverse transcription was performed without the enzyme, therefore eliminating possible DNA contamination. These results demonstrated that in S. suis, yefM and yoeB are actively co-transcribed, thus forming a bicistronic operon.

Bottom Line: Overproduction of S. suis YoeB toxin inhibited the growth of E. coli, and the toxicity of S. suis YoeB could be alleviated by the antitoxin YefM from S. suis and Streptococcus pneumoniae, but not by E. coli YefM.In a murine infection model, deletion of the yefM-yoeB locus had no effect on the virulence of S. suis serotype 2.Collectively, our data suggested that the yefM-yoeB locus of S. suis is an active TA system without the involvement of virulence.

View Article: PubMed Central - PubMed

Affiliation: 1] State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, 430070, China [2] Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.

ABSTRACT
Toxin-antitoxin (TA) systems are widely prevalent in the genomes of bacteria and archaea. These modules have been identified in Escherichia coli and various other bacteria. However, their presence in the genome of Streptococcus suis, an important zoonotic pathogen, has received little attention. In this study, we describe the identification and characterization of a type II TA system, comprising the chromosomal yefM-yoeB locus of S. suis. The yefM-yoeB locus is present in the genome of most serotypes of S. suis. Overproduction of S. suis YoeB toxin inhibited the growth of E. coli, and the toxicity of S. suis YoeB could be alleviated by the antitoxin YefM from S. suis and Streptococcus pneumoniae, but not by E. coli YefM. More importantly, introduction of the S. suis yefM-yoeB system into E. coli could affect cell growth. In a murine infection model, deletion of the yefM-yoeB locus had no effect on the virulence of S. suis serotype 2. Collectively, our data suggested that the yefM-yoeB locus of S. suis is an active TA system without the involvement of virulence.

No MeSH data available.


Related in: MedlinePlus