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Published on: June 11, 2015
MvaT Family Proteins Encoded on IncP-7 Plasmid pCAR1 and the Host Chromosome Regulate the Host Transcriptome
Choong-Soo Yun1, Yurika Takahashi2, Masaki Shintani3
1Biotechnology Research Center, The University of Tokyo, Tokyo, Japan Agricultural Bioinformatics Research Unit, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
Abstract:
MvaT proteins are members of the H-NS family of proteins in pseudomonads. The IncP-7 conjugative plasmid pCAR1 carries an mvaT-homologous gene, pmr. In Pseudomonas putida KT2440 bearing pCAR1, pmr and the chromosomally carried homologous genes, turA and turB, are transcribed at high levels, and Pmr interacts with TurA and TurB in vitro. In the present study, we clarified how the three MvaT proteins regulate the transcriptome of P. putida KT2440(pCAR1). Analyses performed by a modified chromatin immunoprecipitation assay with microarray technology (ChIP-chip) suggested that the binding regions of Pmr, TurA, and TurB in the P. putida KT2440(pCAR1) genome are almost identical; nevertheless, transcriptomic analyses using mutants with deletions of the genes encoding the MvaT proteins during the log and early stationary growth phases clearly suggested that their regulons were different. Indeed, significant regulon dissimilarity was found between Pmr and the other two proteins. Transcription of a larger number of genes was affected by Pmr deletion during early stationary phase than during log phase, suggesting that Pmr ameliorates the effects of pCAR1 on host fitness more effectively during the early stationary phase. Alternatively, the similarity of the TurA and TurB regulons implied that they might play complementary roles as global transcriptional regulators in response to plasmid carriage.
Insights
Pseudomonas MvaT proteins Pmr, TurA, and TurB regulate gene expression differently, despite binding similar genomic regions. Pmr impacts host fitness more during stationary phase, while TurA and TurB may have complementary roles.
Area of Science:
- Microbiology
- Molecular Biology
- Genomics
Background:
- MvaT proteins are H-NS family regulators in pseudomonads.
- The IncP-7 conjugative plasmid pCAR1 encodes the MvaT-homologous gene, pmr.
- Pmr, and chromosomal TurA and TurB, are highly transcribed in Pseudomonas putida KT2440(pCAR1) and interact in vitro.
Purpose of the Study:
- To elucidate the distinct roles of Pmr, TurA, and TurB in regulating the P. putida KT2440(pCAR1) transcriptome.
- To investigate differences in regulons despite similar binding sites.
- To understand the impact of these regulators on host fitness during different growth phases.
Main Methods:
- Modified chromatin immunoprecipitation assay with microarray technology (ChIP-chip) to identify binding regions.
- Transcriptomic analysis of deletion mutants during log and early stationary phases.
- Comparative analysis of regulon differences.
Main Results:
- Pmr, TurA, and TurB share nearly identical genomic binding regions.
- Deletion mutants revealed distinct and dissimilar regulons, especially between Pmr and the other two.
- Pmr deletion affected more genes during the early stationary phase, indicating a role in mitigating plasmid effects on host fitness.
- TurA and TurB showed similar regulons, suggesting complementary functions.
Conclusions:
- Despite overlapping binding sites, Pmr, TurA, and TurB exhibit distinct transcriptional regulatory roles.
- Pmr plays a significant role in host adaptation during the early stationary phase.
- TurA and TurB likely function complementarily as global regulators in response to plasmid pCAR1 carriage.
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