Dataset Information

Bacteriophage T4 MotA activator and the ?-flap tip of RNA polymerase target the same set of ?70 carboxyl-terminal residues.

ABSTRACT: Sigma factors, the specificity subunits of RNA polymerase, are involved in interactions with promoter DNA, the core subunits of RNA polymerase, and transcription factors. The bacteriophage T4-encoded activator, MotA, is one such factor, which engages the C terminus of the Escherichia coli housekeeping sigma factor, ?(70). MotA functions in concert with a phage-encoded co-activator, AsiA, as a molecular switch. This process, termed sigma appropriation, inhibits host transcription while activating transcription from a class of phage promoters. Previous work has demonstrated that MotA contacts the C terminus of ?(70), H5, a region that is normally bound within RNA polymerase by its interaction with the ?-flap tip. To identify the specific ?(70) residues responsible for interacting with MotA and the ?-flap tip, we generated single substitutions throughout the C terminus of ?(70). We find that MotA targets H5 residues that are normally engaged by the ?-flap. In two-hybrid assays, the interaction of ?(70) with either the ?-flap tip or MotA is impaired by alanine substitutions at residues Leu-607, Arg-608, Phe-610, Leu-611, and Asp-613. Transcription assays identify Phe-610 and Leu-611 as the key residues for MotA/AsiA-dependent transcription. Phe-610 is a crucial residue in the H5/?-flap tip interaction using promoter clearance assays with RNA polymerase alone. Our results show how the actions of small transcriptional factors on a defined local region of RNA polymerase can fundamentally change the specificity of polymerase.

SUBMITTER: Bonocora RP

PROVIDER: S-EPMC3234753 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Bacteriophage T4 MotA activator and the β-flap tip of RNA polymerase target the same set of σ70 carboxyl-terminal residues.

Bonocora Richard P RP Decker Phillip K PK Glass Stephanie S Knipling Leslie L Hinton Deborah M DM

The Journal of biological chemistry 20110912 45

Sigma factors, the specificity subunits of RNA polymerase, are involved in interactions with promoter DNA, the core subunits of RNA polymerase, and transcription factors. The bacteriophage T4-encoded activator, MotA, is one such factor, which engages the C terminus of the Escherichia coli housekeeping sigma factor, σ(70). MotA functions in concert with a phage-encoded co-activator, AsiA, as a molecular switch. This process, termed sigma appropriation, inhibits host transcription while activating ...[more]

PMID: 21911499

Similar Datasets

Project description:Phage T4 has provided countless contributions to the paradigms of genetics and biochemistry. Its complete genome sequence of 168,903 bp encodes about 300 gene products. T4 biology and its genomic sequence provide the best-understood model for modern functional genomics and proteomics. Variations on gene expression, including overlapping genes, internal translation initiation, spliced genes, translational bypassing, and RNA processing, alert us to the caveats of purely computational methods. The T4 transcriptional pattern reflects its dependence on the host RNA polymerase and the use of phage-encoded proteins that sequentially modify RNA polymerase; transcriptional activator proteins, a phage sigma factor, anti-sigma, and sigma decoy proteins also act to specify early, middle, and late promoter recognition. Posttranscriptional controls by T4 provide excellent systems for the study of RNA-dependent processes, particularly at the structural level. The redundancy of DNA replication and recombination systems of T4 reveals how phage and other genomes are stably replicated and repaired in different environments, providing insight into genome evolution and adaptations to new hosts and growth environments. Moreover, genomic sequence analysis has provided new insights into tail fiber variation, lysis, gene duplications, and membrane localization of proteins, while high-resolution structural determination of the "cell-puncturing device," combined with the three-dimensional image reconstruction of the baseplate, has revealed the mechanism of penetration during infection. Despite these advances, nearly 130 potential T4 genes remain uncharacterized. Current phage-sequencing initiatives are now revealing the similarities and differences among members of the T4 family, including those that infect bacteria other than Escherichia coli. T4 functional genomics will aid in the interpretation of these newly sequenced T4-related genomes and in broadening our understanding of the complex evolution and ecology of phages-the most abundant and among the most ancient biological entities on Earth.

Dataset Information

Bacteriophage T4 MotA activator and the ?-flap tip of RNA polymerase target the same set of ?70 carboxyl-terminal residues.

Publications

Bacteriophage T4 MotA activator and the β-flap tip of RNA polymerase target the same set of σ70 carboxyl-terminal residues.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets