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. Chromosome Conformation Capture-on-chip analysis (4C) at the Hoxd locus in developing caeca at E13.5, Array data were quantile normalized within 4C/input 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 250 bp.
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. Chromosome Conformation Capture (4C seq) at the HoxD locus in developing caeca at E13.5
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 Transcriptional activity at the HoxD locus in developing caeca at E13.5
Project description:The emergence and evolution of digits was an essential step in the success of the tetrapod lineage. Amongst the key players, Hoxd genes were functionally co-opted in the developing digital plate, where they help organize growth and patterns. To understand both the evolutionary recruitment and transcriptional regulation of this genomic locus, we analyzed its architecture and chromatin status in developing digits, combined with a deletion approach in vivo. We show that the active and inactive parts of the gene cluster adopt opposite spatial configurations, corresponding to different chromatin domains. Active genes are contacted by several regulatory islands, located within a neighboring gene desert, which contribute quantitatively or qualitatively to the global transcriptional readout. We refer to this novel type of control as a ‘regulatory archipelago’ and discuss the value of this concept to understand both the morphological flexibility of tetrapod digits and the robustness of the underlying developmental process. Chromosome Conformation Capture-on-chip analysis (4C) at the Hoxd locus in developing limbs and brain at E12.5
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.
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