Project description:Purpose: Validate HiChIP-identified long-range chromatin interactions at the TFAP2C locus, in a viewpoint-specific manner. Methods: UMI-4C libraries targeting 3 individual viewpoints at the TFAP2C locus were generated in duplicate, in surface ectoderm cells with and without p63. Replicates were sequenced on Illumina NextSeq sequencer, and reads were aligned and filtered for valid long-range interactions using HiCPro. Results: Dynamic long-range interactions at the TFAP2C locus were detected with and without p63 in surface ectoderm cells. Conclusion: Long-range interactions detected via HiChIP were confirmed in the surface ectoderm by this technique, validating the HiChIP method through an orthogonal approach.
Project description:Purpose: Assess changes in the three-dimensional (3D) chromatin architecture during surface ectoderm commitment and evaluate changes in 3D chromatin architecture in human embryonic stem cells and surface ectoderm cells with and without p63. Methods: Cohesin HiChIP profiles for human embryonic stem cells and surface ectoderm cells with and without p63 were generated in triplicate with deep sequencing on the Illumina HiSeq 4000 sequencer. Using HiC-Pro, paired end reads were aligned to hg19, duplicate reads were removed, and then were assigned to MboI restriction fragments, filtered for valid interactions, and used to generate binned interaction matrices of 10 kb resolution. Contacts were called using FitHiC and filtered for counts >= 10 and FDR < 0.001. Results: The greatest change in 3D chromatin architecture was observed between human embryonic stem cells and surface ectoderm cells, while moderate changes were observed in human embryonic stem cells with and without p63, and limited changes were observed in surface ectoderm cells with and without p63. Conclusion: Both p63 and the surface ectoderm morphogens direct changes in chromatin folding to establish the 3D chromatin landscape in the surface ectoderm.
Project description:Purpose: Evaluate p63 regulation of gene expression in human embryonic stem cells and the surface ectoderm Methods: RNA profiles for human embyronic stem cells and surface ectoderm cells with and without p63 using deep sequencing, in duplicate, on Illumina NextSeq 500 sequencer. Quality of reads were checked by fastqc. Reads were aligned to hg19 genome using tophat and FPKM values were generated using Homer. Results: p63 is largely unable to regulate gene expression in pluripotent cells, but acts primarily as a repressor in the surface ectoderm. Conclusion: p63 regulation of gene expression is dependent on the changes the cell undergoes during surface ectoderm commitment
Project description:Purpose: Evaluate changes in chromatin accessibility between human embryonic stem cells and surface ectoderm cells with and without the transcription factor p63. Method: Chromatin accessibility profiles for human embryonic stem cells and surface ectoderm with and without p63 were generated by deep sequencing, in duplicate, with the Illumina NextSeq sequencer. Quality reads were assessed by fastq. Reads were aligned using Bowtie2, PCR duplicates and mitochondrial DNA were discarded, and peak calling was completed using MACS2. Non-reproducible peaks were filtered out by IDR with an FDR of 5%. Results: p63 fails to modify chromatin accessibility when ectopically expressed in human embryonic stem cells; differentiation of human embryonic stem cells to surface ectoderm results in the closure of some regions open in pluripotent cells and the opening of new regions; and loss of p63 in the surface ectoderm results in increased accessibility of 1/3 of the regions opened during surface ectoderm differentiation. Conclusion: p63's ability to modify chromatin accessibility is dependent upon the underlying epigenetic landscape, and when it can modify the landscape, it does so by closing regions that become open during ectoderm differentiation.
Project description:We developed a targeted chromosome conformation capture (4C) approach that uses unique molecular identifiers (UMI) to derive high complexity quantitative chromosome contact profiles with controlled signal to noise ratios. We demonstrate that the method improves the sensitivity and specificity for detection of long-range chromosomal interactions, and that it allows the design of interaction screens with predictable statistical power. UMI-4C robustly quantifies contact intensity changes between cell types and conditions, opening the way toward incorporation of long-range interactions in quantitative models of gene regulation. We constructed UMI-4C profiles of 13 different genomic loci (viewpoints) in five different cell lines, in order to study the 3D chromatin contact maps of these selected loci. The coordinates for these viewpoints are: G1p1 chrX:48646542; baitG1_3_5kb chrX:48641393; bait_50kb chrX:48595987; bait_165kb chrX:48476525; ANK1 chr8:41654693; hbb_3HS chr11:5221346; hbb_HBB chr11:5248714; hbb_HBBP1_G1 chr11:5266532; HBB_HBE chr11:5292159; HBB_HS2 chr11:5301345; HBB_HS3 chr11:5306690; HBB_HS5 chr11:5313539; HBB_HBD chr11:5256597
Project description:We developed a targeted chromosome conformation capture (4C) approach that uses unique molecular identifiers (UMI) to derive high complexity quantitative chromosome contact profiles with controlled signal to noise ratios. We demonstrate that the method improves the sensitivity and specificity for detection of long-range chromosomal interactions, and that it allows the design of interaction screens with predictable statistical power. UMI-4C robustly quantifies contact intensity changes between cell types and conditions, opening the way toward incorporation of long-range interactions in quantitative models of gene regulation.
Project description:We developed a targeted chromosome conformation capture (4C) approach that uses unique molecular identifiers (UMI) to derive high complexity quantitative chromosome contact profiles with controlled signal to noise ratios. We demonstrate that the method improves the sensitivity and specificity for detection of long-range chromosomal interactions, and that it allows the design of interaction screens with predictable statistical power. UMI-4C robustly quantifies contact intensity changes between cell types and conditions, opening the way toward incorporation of long-range interactions in quantitative models of gene regulation.
Project description:The HASTER promoter region is a cis-regulatory element that stabilizes the transcription of HNF1A, preventing silencing or overexpression. We have generated a mouse model where the promoter of Haster has been specifically deleted in liver (Haster loxP/loxP; AlbCre). In liver the prevailing consequence is upregulation of HNF1A. We performed UMI-4C experiments to assess how Haster inactivation remodel 3D chromatin interactions of the Hnf1a promoter using the Hnf1a promoter as viewpoint (V1, Hnf1a promoter upstream CTCF site viewpoint; V2, Hnf1a promoter VP).
Project description:The transcription factor p63 is a master regulator of ectoderm development essential for epidermal specification. Although previous studies have highlighted the role of p63 triggering the epidermal transcriptomic program, its precise mechanism of target gene regulation in the complex context of a developing embryo remains poorly understood. Here, we used zebrafish embryos to analyze in vivo how p63 regulates the expression of its target genes during development. We generated tp63-knock-out mutants that recapitulate human phenotypes and show down-regulated epidermal gene expression. Following p63-binding dynamics during development, we found two distinct functions clearly separated in space and time. During early development, p63 binds enhancers associated to neural genes, where it limits Sox3 binding and reduces the expression of these neural genes. Indeed, we show that p63 and Sox3 are co-expressed in the neural plate border. Later in development, p63 binds enhancers associated to epidermal genes and promotes their expression, acting as a pioneer factor, as it binds to non-accessible chromatin and is required for its opening. Therefore, our results suggest that p63 is an important regulator of cell fate decisions during ectoderm specification, promoting the epidermal fate and inhibiting the neural program.
Project description:The transcription factor p63 is a master regulator of ectoderm development essential for epidermal specification. Although previous studies have highlighted the role of p63 triggering the epidermal transcriptomic program, its precise mechanism of target gene regulation in the complex context of a developing embryo remains poorly understood. Here, we used zebrafish embryos to analyze in vivo how p63 regulates the expression of its target genes during development. We generated tp63-knock-out mutants that recapitulate human phenotypes and show down-regulated epidermal gene expression. Following p63-binding dynamics during development, we found two distinct functions clearly separated in space and time. During early development, p63 binds enhancers associated to neural genes, where it limits Sox3 binding and reduces the expression of these neural genes. Indeed, we show that p63 and Sox3 are co-expressed in the neural plate border. Later in development, p63 binds enhancers associated to epidermal genes and promotes their expression, acting as a pioneer factor, as it binds to non-accessible chromatin and is required for its opening. Therefore, our results suggest that p63 is an important regulator of cell fate decisions during ectoderm specification, promoting the epidermal fate and inhibiting the neural program.