Project description:Higher-order chromosomal organization for transcription regulation is poorly understood in eukaryotes. Using genome-wide Chromatin Interaction Analysis with Paired-End-Tag sequencing (ChIA-PET), we mapped long-range chromatin interactions associated with RNA polymerase II in human cells and uncovered widespread promoter-centered intragenic, extragenic, and intergenic interactions. These interactions further aggregated into higher-order clusters, wherein proximal and distal genes were engaged through promoter-promoter interactions. Most genes with promoter-promoter interactions were active and transcribed cooperatively, and some interacting promoters could influence each other implying combinatorial complexity of transcriptional controls. Comparative analyses of different cell lines showed that cell-specific chromatin interactions could provide structural frameworks for cell-specific transcription, and suggested significant enrichment of enhancer-promoter interactions for cell-specific functions. Furthermore, genetically-identified disease-associated noncoding elements were found to be spatially engaged with corresponding genes through long-range interactions. Overall, our study provides insights into transcription regulation by three-dimensional chromatin interactions for both housekeeping and cell-specific genes in human cells. RNA polymerase II (RNAPII) bound chromatin interactions were extracted with Chromatin Interaction Analysis with Paired-End Tag (ChIA-PET) sequencing, in order to study the transcription regulations with RNAPII-associated long-range chromatin interactions. Five cell lines, namely MCF7 (ATCC# HTB-22), K562 (ATCC# CCL-243), HCT116 (ATCC# CCL-247), HeLa (ATCC# CCL-2.2), and NB4 (Roussel and Lanotte, 2001) (provided by Dr. Sherman Weissman, Yale University), were grown under standard culture conditions and harvested at log phase. Harvested cells were cross-linked using 1% formaldehyde followed by neutralization with 0.2M glycine. Chromatin was isolated and subjected to ChIA-PET protocol as described in Fullwood et al (Fullwood et al: An oestrogen-receptor-alpha-bound human chromatin interactome. Nature 2009, 462(7269):58-64). The ChIA-PET sequence reads were processed and analyzed using ChIA-PET Tool (Li et al: ChIA-PET tool for comprehensive chromatin interaction analysis with paired-end tag sequencing. Genome Biol 2010, 11(2):R22).
Project description:We developed Chromatin Interaction Analysis by Paired-End Tag sequencing (ChIA-PET) for de novo detection of global chromatin interactions, and comprehensively mapped the chromatin interaction network bound by estrogen receptor α (ERα) in the human genome. We performed 454 and Illumina sequencing analyses. Keywords: Epigenetics Using 454, we examined 3 libraries: IHM001 (Estrogen Receptor ChIA-PET), IHM043 (Estrogen Receptor ChIP-PET) and IHM062 (IgG ChIA-PET) Using Illumina, we examined 4 libraries: IHM001 (Estrogen Receptor ChIA-PET replicate 1, Paired End Sequencing), IHH015 (Estrogen Receptor ChIA-PET replicate 2, Paired End Sequencing), H3K4me3 ChIP-Seq and RNA polymerase II ChIP-Seq
Project description:Ronin knockout is embryonic lethal and Ronin knockout ES cells are not viable. Here we used CreER2; Roninflox/flox mouse ES cells to induce Ronin knockout by tamoxfien treatment in comparison to control Roninflox/flox cells to study Ronin knockout related transcriptional changes.
Project description:Ronin (THAP11), an idiosyncratic DNA-binding protein that evolved from a primordial DNA transposon by molecular domestication, recognizes a hyperconserved promoter sequence through which it controls a variety of developmentally and metabolically essential genes in pluripotent stem cells. However, it remains unclear whether Ronin or related THAP proteins perform similar functions elsewhere in development. Here, we present evidence indicating that Ronin performs a novel function within the nascent heart as it arises from the mesoderm and forms a four-chambered organ. We show that Ronin is vital for cardiogenesis during midgestation through its control of a core set of critical genes. The activity of Ronin coincided with the recruitment of its cofactor, Hcf-1, and the elevation of H3K4me3 levels at specific target genes, suggesting the involvement of an epigenetic mechanism. On the strength of these findings, we propose that Ronin activity during cardiogenesis may offer a template that could be used to understand how important gene programs are sustained across different cell types within a developing organ, such as the heart.
Project description:RNA Polymerase II ChIA-PET data has revealed enhancers that are active in a profiled cell type and the genes that the enhancers regulate through chromatin interactions. The most commonly used computational method for analyzing ChIA-PET data, the ChIA-PET Tool, discovers interaction anchors at a spatial resolution that is insufficient to accurately identify individual enhancers. We introduce $Germ$, a computational method that estimates the likelihood that any two narrowly defined genomic locations are jointly occupied by RNA Polymerase II. $Germ$ takes a blind deconvolution approach to simultaneously estimate the likelihood of RNA Polymerase II occupation as well as a model of the arrangement of read alignments relative to locations occupied by RNA Polymerase II. Both types of information are utilized to estimate the likelihood that RNA Polymerase II jointly occupies any two genomic locations. We apply $Germ$ to RNA Polymerase II ChIA-PET data from embryonic stem cells to identify the genomic locations that are jointly occupied along with transcription start sites. We show that these genomic locations align more closely with features of active enhancers measured by ChIP-Seq than the locations identified using the ChIA-PET Tool. We also apply $Germ$ to RNA Polymerase II ChIA-PET data from motor neuron progenitors. Based on the $Germ$ results, we observe that a combination of cell type specific and cell type independent regulatory interactions are utilized by cells to regulate gene expression.
Project description:Conditional knockout of the transcription factor Ronin (Thap11) in retinal progenitor cells (RPCs) results in a profound failure cell proliferation resulting in a hypoplastic adult retina that also suffers from photoreceptor degeneration. The goal of this study was to determine which genes are deregulated in response to loss of Ronin transcription factor activity in the developing retina. We generated Ronin flox/flox (Control) and Chx10-Cre::GFP+/tg; Ronin flox/flox (CKO) mice, in which Ronin loss occurs specifically within RPCs, and performed RNA-Seq analysis of embryonic day E14.5 (E14.5) retinae. Three independent pools of control and Ronin CKO retinae were collected consisting of a minimum of 10 retinae per pool and total RNA was extracted followed by polyA selection, fractionation (200-500 nucleotide range) and generation of cDNA. The resulting DNA was then used for standard Illumina adaptor ligation and sequencing. This experiment revealed decreased expression of a large group of mitochondrial genes including components of the electron transport chain (ETC), which have been recently implicated as direct regulators of the cell cycle.
Project description:Conditional knockout of the transcription factor Ronin (Thap11) in retinal progenitor cells (RPCs) results in a profound failure cell proliferation resulting in a hypoplastic adult retina that also suffers from photoreceptor degeneration. The goal of this study was to determine the genes that are transcriptionally regulated by Ronin during retinogenesis. P0 wild type retinae (CD-1 background) were pooled (>10 each) in ice-cold 1X PBS and immediately processed for chromatin extraction, fragmentation and immunoprecipitation using custom antibodies against Ronin G4275 (Dejosez et al., 2010), G4275 preimmune serum or normal rabbit IgG (Santa Cruz, sc-2027). The immunoprecipitated DNA fragments were then sequenced using the Ion Torrent PGM system.