Volume 6 Supplement 1

Epigenetics and Chromatin: Interactions and processes

Open Access

The 4-D landscape of the inflammatory response

  • Argyris Papantonis1, 2
Epigenetics & Chromatin20136(Suppl 1):P64

DOI: 10.1186/1756-8935-6-S1-P64

Published: 18 March 2013

Background

It is widely accepted that chromatin ‘responds’ to physiological cues via protein:DNA interactions and nucleosome rearrangement [1, 2], and that transcription plays a key role in its higher-order organization [3]. What remains elusive is how the nuclear landscape reshapes, in 3-D space and time, to facilitate such responses to unfold.

Materials and methods

We add tumour necrosis factor α (TNFα) to primary human endothelial cells and induce the inflammatory cascade; this is orchestrated by the transcription factor NF-κB [4]. We monitor the response for 0-85 min post-induction using ChIP nucleosome-positioning studies, and chromosome conformation capture, all coupled to next-generation sequencing. We also apply a new approach, where the isolation of ‘transcription factories’ [5] is followed by RNA-seq to uncover nascent transcriptomes.

Results

First, we redefine early, intermediate, late, and oscillating TNFα-responsive genes, based on changing levels of nascent RNA. We then examine how these co-associate in specialized ‘factories’, some of which further specialize in transcribing responsive non-coding genes [6]. Contacts are driven by NF-κB, and evolve as genes are differentially turned on and off over time. We also monitor nucleosome rearrangements genome-wide; these correlate with poised promoters before induction, and with nucleosome depletion as a result of transcriptional activation, NF-κB binding, enhancer activity in TNFα-stimulated chromosomal domains.

Conclusions

We provide evidence for a prompt, within <30 min, reshaping of the genome in response to inflammation. This entails de novo associations of co-regulated coding and non-coding sequences in specialized 3-D networks that evolve over time, as well as extensive nucleosome depletion. We expect all extracellular cues to signal through analogous specialized networks and reassess our parsimonious model [7] for transcriptional regulation accordingly.

Declarations

Acknowledgements

This work is supported by the BBSRC via the ERASysBio+/FP7 initiative.

Authors’ Affiliations

(1)
Sir William Dunn School of Pathology, University of Oxford
(2)
Center for Molecular Medicine, University of Cologne

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Copyright

© Papantonis; licensee BioMed Central Ltd. 2013

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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