Evolution of Context Dependent Regulation by Expansion of Feast/Famine Regulatory Proteins
Ontology highlight
ABSTRACT:
ORGANISM(S): Halobacterium salinarum NRC-1
PROVIDER: GSE62052 | GEO | 2014/10/03
SECONDARY ACCESSION(S): PRJNA263040
REPOSITORIES: GEO
Similar Datasets
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2014-10-03 | E-GEOD-62052 | biostudies-arrayexpress
Project description:BackgroundExpansion of transcription factors is believed to have played a crucial role in evolution of all organisms by enabling them to deal with dynamic environments and colonize new environments. We investigated how the expansion of the Feast/Famine Regulatory Protein (FFRP) or Lrp-like proteins into an eight-member family in Halobacterium salinarum NRC-1 has aided in niche-adaptation of this archaeon to a complex and dynamically changing hypersaline environment.ResultsWe mapped genome-wide binding locations for all eight FFRPs, investigated their preference for binding different effector molecules, and identified the contexts in which they act by analyzing transcriptional responses across 35 growth conditions that mimic different environmental and nutritional conditions this organism is likely to encounter in the wild. Integrative analysis of these data constructed an FFRP regulatory network with conditionally active states that reveal how interrelated variations in DNA-binding domains, effector-molecule preferences, and binding sites in target gene promoters have tuned the functions of each FFRP to the environments in which they act. We demonstrate how conditional regulation of similar genes by two FFRPs, AsnC (an activator) and VNG1237C (a repressor), have striking environment-specific fitness consequences for oxidative stress management and growth, respectively.ConclusionsThis study provides a systems perspective into the evolutionary process by which gene duplication within a transcription factor family contributes to environment-specific adaptation of an organism.
| S-EPMC4236453 | biostudies-literature
Project description:We validated context dependent regulation by two FFRPs AsnC and VNG1237C by deleting the FFRP and testing the effect on downstream target genes. For validtion of AsnC condition specific regulation we grew wild-type and delta-AsnC in the presence of 4mM paraquat (PQ) and samples at 1 and 160 minutes post addition of this sub-lethal dose of PQ. For validation of VNG1237C we grew wild-type and delta-VNG1237C in a standard growth curve sampling at OD 0.18 and 1.15. The asnC deletion strain (M-bM-^HM-^FasnC) and the control M-bM-^HM-^Fura3 strain were grown in 4mM paraquat (PQ) and were sampled at 1 and 160 minutes after PQ addition. Sampling timing for M-bM-^HM-^FVNG1237C was designed such that the starting ODs were as similar as possible and once an OD of 1.17 was reached for M-bM-^HM-^Fura3 the M-bM-^HM-^FVNG1237C was sampled at this same time point.
2014-10-02 | E-GEOD-61975 | biostudies-arrayexpress
Project description:We validated context dependent regulation by two FFRPs AsnC and VNG1237C by deleting the FFRP and testing the effect on downstream target genes. For validtion of AsnC condition specific regulation we grew wild-type and delta-AsnC in the presence of 4mM paraquat (PQ) and samples at 1 and 160 minutes post addition of this sub-lethal dose of PQ. For validation of VNG1237C we grew wild-type and delta-VNG1237C in a standard growth curve sampling at OD 0.18 and 1.15.
2014-10-02 | GSE61975 | GEO
Project description:Chromatin immunoprecipitation and microarray hybridization (ChIP-chip) experiments were carried out for all 8 FFRPs in H. salinarum NRC-1. To study the FFRP localization in both nutrient-replete and -deplete conditions, all strains were grown in CDM and genomic DNA of samples was harvested in both early log phase and late log phase. DNA from FFRP-bound regions was collected through c-Myc-tagged protein complexes and unenriched non-IP DNA were each labeled and hybridized to the whole genome tiling array.
2014-10-03 | E-GEOD-62051 | biostudies-arrayexpress
Project description:Chromatin immunoprecipitation and microarray hybridization (ChIP-chip) experiments were carried out for all 8 FFRPs in H. salinarum NRC-1.
2014-10-03 | GSE62051 | GEO
Project description:Since the discovery of the Escherichia coli leucine-responsive regulatory protein (Lrp) almost 50 years ago, hundreds of Lrp homologs have been discovered, occurring in 45% of sequenced bacteria and almost all sequenced archaea. Lrp-like proteins are often referred to as the feast/famine regulatory proteins (FFRPs), reflecting their common regulatory roles. Acting as either global or local transcriptional regulators, FFRPs detect the environmental nutritional status by sensing small effector molecules (usually amino acids) and regulate the expression of genes involved in metabolism, virulence, motility, nutrient transport, stress tolerance, and antibiotic resistance to implement appropriate behaviors for the specific ecological niche of each organism. Despite FFRPs' complexity, a significant role in gene regulation, and prevalence throughout prokaryotes, the last comprehensive review on this family of proteins was published about a decade ago. In this review, we integrate recent notable findings regarding E. coli Lrp and other FFRPs across bacteria and archaea with previous observations to synthesize a more complete view on the mechanistic details and biological roles of this ancient class of transcription factors.
| S-EPMC9239533 | biostudies-literature
Project description:The classification feast/famine regulatory proteins (FFRPs) encompasses archaeal DNA-binding proteins with Escherichia coli transcription factors, the leucine-responsive regulatory protein and the asparagine synthase C gene product. In this paper, we describe two forms of the archaeal FFRP FL11 (pot0434017), both assembled from dimers. When crystallized, a helical cylinder is formed with six dimers per turn. In contrast, in solution, disks are formed, most likely consisting of four dimers each; an observation by cryoelectron microscopy. Whereas each dimer binds a 13-bp sequence, different forms will discriminate between promoters, based on the numbers of repeating 13-bp sequences, and types of linkers inserted between them, which are either of 7-8 or approximately 18 bp. The amino acid sequences of these FFRPs are designed to form the same type of 3D structures, and the transition between their assembly forms is regulated by interaction with small molecules. These considerations lead us to propose a possible mechanism for regulating a number of genes by varying assembly forms and by combining different FFRPs into these assemblies, responding to environmental changes.
| S-EPMC365707 | biostudies-literature
Project description:Rv3291c gene from Mycobacterium tuberculosis codes for a transcriptional regulator belonging to the (leucine responsive regulatory protein/regulator of asparigine synthase C gene product) Lrp/AsnC-family. We have identified a novel effector-binding site from crystal structures of the apo protein, complexes with a variety of amino acid effectors, X-ray based ligand screening and qualitative fluorescence spectroscopy experiments. The new effector site is in addition to the structural characterization of another distinct site in the protein conserved in the related AsnC-family of regulators. The structures reveal that the ligand-binding loops of two crystallographically independent subunits adopt different conformations to generate two distinct effector-binding sites. A change in the conformation of the binding site loop 100-106 in the B subunit is apparently necessary for octameric association and also allows the loop to interact with a bound ligand in the newly identified effector-binding site. There are four sites of each kind in the octamer and the protein preferentially binds to aromatic amino acids. While amino acids like Phe, Tyr and Trp exhibit binding to only one site, His exhibits binding to both sites. Binding of Phe is accompanied by a conformational change of 3.7 A in the 75-83 loop, which is advantageously positioned to control formation of higher oligomers. Taken together, the present studies suggest an elegant control mechanism for global transcription regulation involving binding of ligands to the two sites, individually or collectively.
| S-EPMC2175373 | biostudies-literature
Project description:Escherichia coli DNA polymerases (Pol) II, IV, and V serve dual roles by facilitating efficient translesion DNA synthesis while simultaneously introducing genetic variation that can promote adaptive evolution. Here we show that these alternative polymerases are induced as cells transition from exponential to long-term stationary-phase growth in the absence of induction of the SOS regulon by external agents that damage DNA. By monitoring the relative fitness of isogenic mutant strains expressing only one alternative polymerase over time, spanning hours to weeks, we establish distinct growth phase-dependent hierarchies of polymerase mutant strain competitiveness. Pol II confers a significant physiological advantage by facilitating efficient replication and creating genetic diversity during periods of rapid growth. Pol IV and Pol V make the largest contributions to evolutionary fitness during long-term stationary phase. Consistent with their roles providing both a physiological and an adaptive advantage during stationary phase, the expression patterns of all three SOS polymerases change during the transition from log phase to long-term stationary phase. Compared to the alternative polymerases, Pol III transcription dominates during mid-exponential phase; however, its abundance decreases to <20% during long-term stationary phase. Pol IV transcription dominates as cells transition out of exponential phase into stationary phase and a burst of Pol V transcription is observed as cells transition from death phase to long-term stationary phase. These changes in alternative DNA polymerase transcription occur in the absence of SOS induction by exogenous agents and indicate that cell populations require appropriate expression of all three alternative DNA polymerases during exponential, stationary, and long-term stationary phases to attain optimal fitness and undergo adaptive evolution.
| S-EPMC3664851 | biostudies-literature