Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Halobacterium salinarum NRC-1 VNG1451C transcription factor ChIP-chip with and without carbon sources

ABSTRACT: Gene regulatory networks play an important role in coordinating biochemical fluxes through diverse metabolic pathways. The modulation of enzyme levels enables efficient utilization of limited resources as organisms dynamically acclimate to nutritional fluctuations in their environment. Here we have identified and characterized a novel nutrient-responsive transcription factor from the halophilic archaea, AgmR. Like TrmB, its thermophilic archaeal homolog, AgmR regulates glycolytic and gluconeogenic pathways in response to sugar availability. However, using high throughput genome-scale experiments, we find that AgmR directly governs the transcription of nearly 100 additional genes encoding enzymes in diverse metabolic pathways. Genome-scale in vivo binding site location data reveals that >60% of these are direct targets. Integration of these systems-scale datasets with metabolic reconstruction models suggests that AgmR, a sequence-specific bacterial-like regulator, interacts with the general transcription factor machinery to coordinate nitrogen and carbon metabolism with the de novo synthesis of cognate cofactors and reducing equivalents, achieving system-wide redox and energy balance. Halobacterium salinarum NRC-1 (ATCC700922) ura3 parent and VNG1451C strains were grown in rich medium (CM, 250 NaCl, 20 g/L MgSO4?7H2O, 3 g/L sodium citrate, 2 g/L KCl, 10 g/L peptone) with or without varying concentrations of glucose or glycerol at 37ÂºC under full-spectrum white light. The cells were cross-linked with 1.2% formaldehyde, then lysed and DNA sheared via sonication. Next cleared cell lysate was subject to immunoprecipitation against an anti-myc antibody. Protein-DNA complexes were purified and DNA was isolated after protease and RNAase treatment. DNA was amplified using universal linkers, labeled directly using Kreatech 547 and 647 dyes. Samples were grown in biological duplicate. Each DNA sample was hybridized against 2 microarrays as dyefilps. At least two experiments (including biological duplicates) were carried out.

ORGANISM(S): Halobacterium sp. NRC-1

SUBMITTER: Baliga Nitin S.

PROVIDER: E-GEOD-13498 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

A single transcription factor regulates evolutionarily diverse but functionally linked metabolic pathways in response to nutrient availability.

Schmid Amy K AK Reiss David J DJ Pan Min M Koide Tie T Baliga Nitin S NS

Molecular systems biology 20090616

During evolution, enzyme-coding genes are acquired and/or replaced through lateral gene transfer and compiled into metabolic pathways. Gene regulatory networks evolve to fine tune biochemical fluxes through such metabolic pathways, enabling organisms to acclimate to nutrient fluctuations in a competitive environment. Here, we demonstrate that a single TrmB family transcription factor in Halobacterium salinarum NRC-1 globally coordinates functionally linked enzymes of diverse phylogeny in respons ...[more]

PMID: 19536205

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Project description:Because iron toxicity and deficiency are equally life threatening, maintaining intracellular iron levels within a narrow optimal range is critical for nearly all known organisms. However, regulatory mechanisms that establish homeostasis are not well understood in organisms that dwell in environments at the extremes of pH, temperature, and salinity. Under conditions of limited iron, the extremophile Halobacterium salinarum, a salt-loving archaeon, mounts a specific response to scavenge iron for growth. We have identified and characterized the role of two transcription factors (TFs), Idr1 and Idr2, in regulating this important response. An integrated systems analysis of TF knockout gene expression profiles and genome-wide binding locations in the presence and absence of iron has revealed that these TFs operate collaboratively to maintain iron homeostasis. In the presence of iron, Idr1 and Idr2 bind near each other at 24 loci in the genome, where they are both required to repress some genes. In contrast, Idr1 and Idr2 are both necessary to activate other genes in a putative a feed forward loop. Even at loci bound independently, the two TFs target different genes with similar functions in iron homeostasis. We discuss conserved and unique features of the Idr1-Idr2 system in the context of similar systems in organisms from other domains of life. Data in this GEO archive are linked to the publication: Schmid AK, Pan M, Sharma K, Baliga NS.2011. Two transcription factors are necessary for iron homeostasis in a salt-dwelling archaeon.Nucleic Acids Res.39(7):2519-33. Cultures containing either the gene encoding the Idr1 or Idr2 transcription factors with c-terminal fusions to the myc epitope were grown to mid-logarithmic phase in the presence or absence of 100 uM FeSO4. Cultures were subjected to ChIP-chip as described in Facciotti, MT, Reiss, DJ, Pan, M, Kaur, A, Vuthoori, M, Bonneau, R, Shannon, P, Srivastava, A, Donohoe, SM, Hood, LE and Baliga, NS. General transcription factor specified global gene regulation in archaea. Proc Natl Acad Sci U S A. 2007;104: 4630-4635. Each Sample is based on two arrrays (one with dye-swap).

Dataset Information

Halobacterium salinarum NRC-1 VNG1451C transcription factor ChIP-chip with and without carbon sources

Publications

A single transcription factor regulates evolutionarily diverse but functionally linked metabolic pathways in response to nutrient availability.

Similar Datasets

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