Chromatin topology and the timing of enhancer function at the HoxD locus
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ABSTRACT:
PROVIDER: PRJNA645387 | ENA |
REPOSITORIES: ENA
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Project description:The HoxD gene cluster is critical for proper limb formation in tetrapods. In the emerging limb buds, different sub-groups of Hoxd genes respond first to a proximal regulatory signal, then to a distal signal that organizes digits. These two regulations are exclusive from one another and emanate separately from two TADs flanking HoxD, both containing a range of appropriate enhancer sequences. The telomeric TAD (T-DOM) contains several enhancers active in presumptive forearm cells and is divided into two sub-TADs separated by a CTCF-rich boundary, which defines two regulatory sub-modules. To understand the importance of this particular regulatory topology to control Hoxd gene transcription in time and space, we either deleted or inverted this sub-TAD boundary, eliminated the CTCF binding sites or inverted the entire T-DOM to exchange the respective positions of the two sub-TADs. The effects of such perturbations on the transcriptional regulation of Hoxd genes illustrates the requirement of this regulatory topology for the precise timing of gene activation. However, the spatial distribution of transcripts is eventually resumed, showing that the presence of enhancers sequences, rather than either their exact topology or a particular chromatin architecture, is the key factor. We also show that the affinity of enhancers to find their natural target genes can overcome the presence of both a strong TAD border and an unfavourable orientation of CTCF sites.
2020-11-10 | GSE154187 | GEO
Project description:The HoxD gene cluster is critical for proper limb formation in tetrapods. In the emerging limb buds, different sub-groups of Hoxd genes respond first to a proximal regulatory signal, then to a distal signal that organizes digits. These two regulations are exclusive from one another and emanate separately from two TADs flanking HoxD, both containing a range of appropriate enhancer sequences. The telomeric TAD (T-DOM) contains several enhancers active in presumptive forearm cells and is divided into two sub-TADs separated by a CTCF-rich boundary, which defines two regulatory sub-modules. To understand the importance of this particular regulatory topology to control Hoxd gene transcription in time and space, we either deleted or inverted this sub-TAD boundary, eliminated the CTCF binding sites or inverted the entire T-DOM to exchange the respective positions of the two sub-TADs. The effects of such perturbations on the transcriptional regulation of Hoxd genes illustrates the requirement of this regulatory topology for the precise timing of gene activation. However, the spatial distribution of transcripts is eventually resumed, showing that the presence of enhancers sequences, rather than either their exact topology or a particular chromatin architecture, is the key factor. We also show that the affinity of enhancers to find their natural target genes can overcome the presence of both a strong TAD border and an unfavourable orientation of CTCF sites.
2020-11-10 | GSE154188 | GEO
Project description:In tetrapods, the HoxD gene cluster is critical for proper limb formation. In the emerging limb buds, different sub-groups of Hoxd genes respond first to a proximal regulatory signal, then to a distal signal that organizes digits. These two regulations emanate from the two TADs flanking HoxD, both containing a range of appropriate enhancer sequences. The telomeric TAD (T-DOM) contains several regulatory elements controlling Hoxd genes, initially in a temporal manner and then in the proximal presumptive forearm. T-DOM is divided into two sub-TADs separated by a CTCF-rich boundary defining two regulatory modules with most limb enhancers concentrated in the more distant module. In order to understand the importance of this regulatory topology to elicit a precise Hoxd gene transcription in time and space, we both deleted or inverted this sub-TAD boundary and eliminated the CTCF binding sites. These perturbations caused a time delay in gene activation, which was subsequently resumed. We then inverted the entire T-DOM to change the respective position of the two sub-TADs, which concomitantly introduced a TAD boundary between HoxD and the inverted T-DOM. This re-arrangement had a stronger impact on the early expression and flattened the Hoxd mRNAs levels. The latter effect was rescued by re-granting access to the enhancers upon deletion of the ectopic boundary. These results highlight the importance of regulatory topologies in the temporal control of gene expression. We also show that, along with time, the affinity of enhancers to find their natural target genes can overcome the presence of both a strong TAD border, and an unfavourable orientation of CTCF sites.
2020-11-10 | GSE154186 | GEO
Project description:Chromatin topology and the timing of enhancer function at the HoxD locus [RNA-seq]
| PRJNA645390 | ENA
Project description:Chromatin topology and the timing of enhancer function at the HoxD locus [4C-seq]
| PRJNA645388 | ENA
Project description:Chromatin topology and the timing of enhancer function at the HoxD locus [ChIP-seq]
| PRJNA645389 | ENA
Project description: Not available
| S-EPMC7733857 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2020-11-10 | GSE154189 | GEO
Project description:The transcriptional activation of Hoxd genes during mammalian limb development involves dynamic interactions with the two Topologically Associating Domains (TADs) flanking the HoxD cluster. In particular, the activation of the most posterior Hoxd genes in developing digits is controlled by regulatory elements located in the centromeric TAD (C-DOM) through long-range contacts. To assess the structure-function relationships underlying such interactions, we measured compaction levels and TAD discreteness using a combination of chromosome conformation capture (4C-seq) and DNA FISH. We challenged the robustness of the TAD architecture by using a series of genomic deletions and inversions that impact the integrity of this chromatin domain and that remodel the long-range contacts. We report multi-partite associations between Hoxd genes and up to three enhancers and show that breaking the native chromatin topology leads to the remodelling of TAD structure. Our results reveal that the re-composition of TADs architectures after severe genomic re-arrangements depends on a boundary-selection mechanism that uses CTCF-mediated gating of long-range contacts in combination with genomic distance and, to a certain extent, sequence specificity.
2017-07-12 | GSE98861 | GEO
Project description:Hox genes are required for the development of the intestinal caecum, a major organ of species eating plants. We have analysed the transcriptional regulation of Hoxd genes in caecal buds and show that they are controlled by a series of enhancers located in a gene desert telomeric to the HoxD cluster. The start site of two neighboring and opposite long non-coding RNAs, Hotdog and Twin of Hotdog, specifically transcribed in the caecum, contacts the expressed Hoxd genes in the framework of a topological domain, a large domain of interactions, which ensures a robust transcription of these genes during caecum budding. We show that hedgehogs have kept this regulatory potential despite the absence of caecum, suggesting that these enhancers are used in other developmental situations. In this context, we discuss some striking similarities between the caecum and the limb buds, suggesting the implementation of a common budding tool-kit. Transcriptional activity at the HoxD locus in developing caeca at E13.5, Array data were quantile normalized within cDNA/genomic DNA replicate groups and scaled to medial feature intensity of 100 using TAS software (Affymetrix). For each genomic position, a data set was generated consisting of all (PM-MM) pairs mapping within a sliding window of 80 bp. For each tissue, two independent RNA extractions, cDNA synthesis and array hybridizations were performed, except for del(1-4i) and del(9-11) mutant caeca.
2013-10-23 | E-GEOD-44362 | biostudies-arrayexpress