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Juan E Suarez - One of the best experts on this subject based on the ideXlab platform.
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modulation of lactobaCillus casei bacteriophage a2 lytic lysogenic cycles by binding of gp25 to the early lytic mrna
Molecular Microbiology, 2016Co-Authors: Begona Carrasco, Susana Escobedo, Juan C Alonso, Juan E SuarezAbstract:The genetic switch of LactobaCillus casei bacteriophage A2 is regulated by the Ci Protein, which represses the early lytic promoter PR and Cro that abolishes expression from the lysogenic promoter PL . Lysogens contain equivalent Ci and cro-gp25 mRNA concentrations, i.e., Ci only partially represses P(R), predicting a lytic cycle dominance. However, A2 generates stable lysogens. This may be due to Gp25 binding to the cro-gp25 mRNA between the ribosomal binding site and the cro start codon, which abolishes its translation. Upon lytic cycle induction, Ci is partially degraded, cro-gp25 mRNA levels increase, and Cro accumulates, launching viral progeny production. The concomitant concentration increase of Gp25 restricts cro mRNA translation, which, together with the low but detectable levels of Ci late during the lytic cycle, promotes reentry of part of the cell population into the lysogenic cycle, thus explaining the low proportion of L. casei lysogens that become lysed (∼ 1%). A2 shares its genetic switch structure with many other Firmicutes phages. The data presented may constitute a model of how these phages make the deCision for lysis versus lysogeny.
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cooperative interaction of Ci Protein regulates lysogeny of lactobaCillus casei by bacteriophage a2
Journal of Virology, 1999Co-Authors: Juan C Alonso, Juan E Suarez, Pilar Garcia, Victor LaderoAbstract:The temperate bacteriophage A2 forms stable lysogens in LactobaCillus casei. The A2-encoded Ci product (Ci), which is responsible for maintaining the A2 prophage in the lysogenic state, has been purified. The Ci Protein, which is a monomer of 25.3 kDa in solution, speCifically binds to a 153-bp DNA fragment that contains two divergent promoters, PL and PR. These promoters mediate transcription from Ci and a putative cro, respectively. Three similar, although not identical, 20-bp inverted repeated DNA segments (operator sites O1, O2, and O3) were found in this segment. Ci selectively interacts with O1, which is placed downstream from the transcription start point of the cro gene, and with O2 and O3, which overlap with the −35 region of the two promoters. Using a heterologous RNA polymerase, we have determined the transcription start points of PL and PR. Ci exerts a negative effect on the in vitro transcription of PR by repositioning the RNA polymerase in a concentration-dependent manner. Ci, when bound to O1 and O2, enhances the positioning of the RNA polymerase with the PL promoter. Our data indicate that the Ci Protein regulates the lytic and lysogenic pathways of the A2 phage.
Aiming Wang - One of the best experts on this subject based on the ideXlab platform.
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the multifunctional Protein Ci of potyviruses plays interlinked and distinct roles in viral genome replication and intercellular movement
Virology Journal, 2015Co-Authors: Ping Deng, Aiming WangAbstract:Background The multifunctional cylindrical inclusion (Ci) Protein of potyviruses contains ATP binding and RNA helicase activities. As part of the viral replication complex, it assists viral genome replication, possibly by binding to RNA and unwinding the RNA duplex. It also functions in viral cell-to-cell movement, likely via the formation of conical structures at plasmodesmata (PD) and the interaction with coat Protein (CP).
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formation of complexes at plasmodesmata for potyvirus intercellular movement is mediated by the viral Protein p3n pipo
PLOS Pathogens, 2010Co-Authors: James C. Carrington, Changwei Zhang, Jian Hong, Ruyi Xiong, Krisitin D Kasschau, Xueping Zhou, Aiming WangAbstract:Intercellular transport of viruses through cytoplasmic connections, termed plasmodesmata (PD), is essential for systemic infection in plants by viruses. Previous genetic and ultrastructural data revealed that the potyvirus cyclindrical inclusion (Ci) Protein is directly involved in cell-to-cell movement, likely through the formation of conical structures anchored to and extended through PD. In this study, we demonstrate that plasmodesmatal localization of Ci in N. benthamiana leaf cells is modulated by the recently discovered potyviral Protein, P3N-PIPO, in a Ci:P3N-PIPO ratio-dependent manner. We show that P3N-PIPO is a PD-located Protein that physically interacts with Ci in planta. The early secretory pathway, rather than the actomyosin motility system, is required for the delivery of P3N-PIPO and Ci to PD. Moreover, Ci mutations that disrupt virus cell-to-cell movement compromise PD-localization capaCity. These data suggest that the Ci and P3N-PIPO complex coordinates the formation of PD-assoCiated structures that faCilitate the intercellular movement of potyviruses in infected plants.
Juan C Alonso - One of the best experts on this subject based on the ideXlab platform.
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modulation of lactobaCillus casei bacteriophage a2 lytic lysogenic cycles by binding of gp25 to the early lytic mrna
Molecular Microbiology, 2016Co-Authors: Begona Carrasco, Susana Escobedo, Juan C Alonso, Juan E SuarezAbstract:The genetic switch of LactobaCillus casei bacteriophage A2 is regulated by the Ci Protein, which represses the early lytic promoter PR and Cro that abolishes expression from the lysogenic promoter PL . Lysogens contain equivalent Ci and cro-gp25 mRNA concentrations, i.e., Ci only partially represses P(R), predicting a lytic cycle dominance. However, A2 generates stable lysogens. This may be due to Gp25 binding to the cro-gp25 mRNA between the ribosomal binding site and the cro start codon, which abolishes its translation. Upon lytic cycle induction, Ci is partially degraded, cro-gp25 mRNA levels increase, and Cro accumulates, launching viral progeny production. The concomitant concentration increase of Gp25 restricts cro mRNA translation, which, together with the low but detectable levels of Ci late during the lytic cycle, promotes reentry of part of the cell population into the lysogenic cycle, thus explaining the low proportion of L. casei lysogens that become lysed (∼ 1%). A2 shares its genetic switch structure with many other Firmicutes phages. The data presented may constitute a model of how these phages make the deCision for lysis versus lysogeny.
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cooperative interaction of Ci Protein regulates lysogeny of lactobaCillus casei by bacteriophage a2
Journal of Virology, 1999Co-Authors: Juan C Alonso, Juan E Suarez, Pilar Garcia, Victor LaderoAbstract:The temperate bacteriophage A2 forms stable lysogens in LactobaCillus casei. The A2-encoded Ci product (Ci), which is responsible for maintaining the A2 prophage in the lysogenic state, has been purified. The Ci Protein, which is a monomer of 25.3 kDa in solution, speCifically binds to a 153-bp DNA fragment that contains two divergent promoters, PL and PR. These promoters mediate transcription from Ci and a putative cro, respectively. Three similar, although not identical, 20-bp inverted repeated DNA segments (operator sites O1, O2, and O3) were found in this segment. Ci selectively interacts with O1, which is placed downstream from the transcription start point of the cro gene, and with O2 and O3, which overlap with the −35 region of the two promoters. Using a heterologous RNA polymerase, we have determined the transcription start points of PL and PR. Ci exerts a negative effect on the in vitro transcription of PR by repositioning the RNA polymerase in a concentration-dependent manner. Ci, when bound to O1 and O2, enhances the positioning of the RNA polymerase with the PL promoter. Our data indicate that the Ci Protein regulates the lytic and lysogenic pathways of the A2 phage.
Pilar Garcia - One of the best experts on this subject based on the ideXlab platform.
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cooperative interaction of Ci Protein regulates lysogeny of lactobaCillus casei by bacteriophage a2
Journal of Virology, 1999Co-Authors: Juan C Alonso, Juan E Suarez, Pilar Garcia, Victor LaderoAbstract:The temperate bacteriophage A2 forms stable lysogens in LactobaCillus casei. The A2-encoded Ci product (Ci), which is responsible for maintaining the A2 prophage in the lysogenic state, has been purified. The Ci Protein, which is a monomer of 25.3 kDa in solution, speCifically binds to a 153-bp DNA fragment that contains two divergent promoters, PL and PR. These promoters mediate transcription from Ci and a putative cro, respectively. Three similar, although not identical, 20-bp inverted repeated DNA segments (operator sites O1, O2, and O3) were found in this segment. Ci selectively interacts with O1, which is placed downstream from the transcription start point of the cro gene, and with O2 and O3, which overlap with the −35 region of the two promoters. Using a heterologous RNA polymerase, we have determined the transcription start points of PL and PR. Ci exerts a negative effect on the in vitro transcription of PR by repositioning the RNA polymerase in a concentration-dependent manner. Ci, when bound to O1 and O2, enhances the positioning of the RNA polymerase with the PL promoter. Our data indicate that the Ci Protein regulates the lytic and lysogenic pathways of the A2 phage.
Begona Carrasco - One of the best experts on this subject based on the ideXlab platform.
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modulation of lactobaCillus casei bacteriophage a2 lytic lysogenic cycles by binding of gp25 to the early lytic mrna
Molecular Microbiology, 2016Co-Authors: Begona Carrasco, Susana Escobedo, Juan C Alonso, Juan E SuarezAbstract:The genetic switch of LactobaCillus casei bacteriophage A2 is regulated by the Ci Protein, which represses the early lytic promoter PR and Cro that abolishes expression from the lysogenic promoter PL . Lysogens contain equivalent Ci and cro-gp25 mRNA concentrations, i.e., Ci only partially represses P(R), predicting a lytic cycle dominance. However, A2 generates stable lysogens. This may be due to Gp25 binding to the cro-gp25 mRNA between the ribosomal binding site and the cro start codon, which abolishes its translation. Upon lytic cycle induction, Ci is partially degraded, cro-gp25 mRNA levels increase, and Cro accumulates, launching viral progeny production. The concomitant concentration increase of Gp25 restricts cro mRNA translation, which, together with the low but detectable levels of Ci late during the lytic cycle, promotes reentry of part of the cell population into the lysogenic cycle, thus explaining the low proportion of L. casei lysogens that become lysed (∼ 1%). A2 shares its genetic switch structure with many other Firmicutes phages. The data presented may constitute a model of how these phages make the deCision for lysis versus lysogeny.