Project description:Genes that are key to cell identity are generally regulated by cell-type-specific enhancer elements bound by transcription factors, some of which facilitate looping to distant gene promoters. In contrast, genes that encode housekeeping functions, whose regulation is essential for normal cell metabolism and growth, generally lack interactions with distal enhancers. We find that Ronin (Thap11) assembles multiple promoters of housekeeping and metabolic genes to regulate gene expression. This behavior is analogous to how enhancers are brought together with promoters to regulate cell identity genes. Thus, Ronin-dependent promoter assemblies provide a mechanism to explain why housekeeping genes can forgo distal enhancer elements and why Ronin is important for cellular metabolism and growth control. We propose that clustering of regulatory elements is a mechanism common to cell identity and housekeeping genes but is accomplished by different factors binding distinct control elements to establish enhancer-promoter or promoter-promoter interactions, respectively.
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: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: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
