Project description:Protein-RNA interaction networks are essential to understand gene regulation control. Identifying the binding sites of RNA-binding proteins (RBPs) by CLIP (UV-crosslinking and immunoprecipitation) represents one of the most powerful methods to map in vivo protein-RNA interactions. However, the traditional CLIP protocol is technically challenging, which requires radioactive labeling and suffers from material loss during PAGE-membrane transfer procedures. Here we introduce a super-efficient CLIP method (GoldCLIP) that omits all gel purification steps. This nonisotopic method allowed us to perform highly reproducible CLIP experiments with classical RBP such as PTB in human cell lines. In principle, our method guarantees sequencing library constructions, providing the protein of interest can be successfully crosslinked to RNAs in living cells. GoldCLIP is readily applicable to diverse factors to uncover their endogenous targets.
Project description:In vivo protein-DNA interactions connect each transcription factor with its direct targets to form a gene network scaffold. To map these protein-DNA interactions comprehensively across entire mammalian genomes, we developed a large-scale chromatin immunoprecipitation assay (ChIPSeq) based on direct ultrahigh-throughput DNA sequencing. This sequence census method was then used to map in vivo binding of the neuron-restrictive silencer factor (NRSF; also known as REST, for repressor element–1 silencing transcription factor) to 1946 locations in the human genome. The data display sharp resolution of binding position [±50 base pairs (bp)], which facilitated our finding motifs and allowed us to identify noncanonical NRSF-binding motifs. These ChIPSeq data also have high sensitivity and specificity [ROC (receiver operator characteristic) area ≥ 0.96] and statistical confidence (P < 10−4), properties that were important for inferring new candidate interactions. These include key transcription factors in the gene network that regulates pancreatic islet cell development. Experiment Overall Design: Exam NRSF binding in Jurkat T cell line
Project description:We report the setup of a new method to map 5-hydroxymethylcytosine (5hmC) genome-wide at CpG resolution. The method combines selective chemical labeling by 5hmC b-glucosyltransferase and exonuclease digestion of the DNA molecules bound to streptavidin beads after biotinylation of the 5-glucosylmethylcytosines. Associated with a straightforward bioinformatic analysis, this new procedure provides a cost-effective and fast method for mapping 5hmC at high resolution.
Project description:Here we present a new version of the DamID method that allows efficient capturing of protein-DNA interactions and mRNA output from the same single cell. With this protocol, we have measured the direct impact of spatial genome positioning and chromatin accessibility on mRNA output in human haploid cells
Project description:Mapping genome-wide 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) at single-base resolution is important to understand their biological functions. We present a cost-efficient mapping method that combines 5hmC-specific restriction enzyme PvuRts1I with a 5hmC enrichment method. The sensitive method enables detection of low abundant 5hmC sites, providing a more complete 5hmC landscape than available bisulfite-based methods. This method generated the first genome-wide 5fC map at single-base resolution. Parallel analyses revealed that 5hmC and 5fC existed with lower abundance and more dynamically in non-CpG context than in CpG context. In the genic region, distribution of 5hmCpG and 5fCpG differed from 5hmCH and 5fCH (H=A, T, C). 5hmC and 5fC were distributed distinctly at regulatory protein-DNA binding sites, depleted in permissive transcription factor binding sites, and enriched at active and poised enhancers. This sensitive bisulfite-conversion free method can be applied to biological samples with limited starting material or low abundance of cytosine modifications. Sensitive mapping of genome-wide 5-hydroxymethylcytosine and 5-formylcytosine in mouse embryonic stem cell at single-base resolution by combining 5-hydroxymethylcytosine specific restriction enzyme PvuRts1I and 5-hydroxymethylcytosine enrichment method (selective chemical labeling or SEAL)
Project description:Here we present a new version of the DamID method that allows efficient capturing of protein-DNA interactions and mRNA output from the same single cell. With this protocol, we have measured the direct impact of spatial genome positioning and chromatin accessibility on mRNA output in mouse embryonic stem cells
Project description:High-order rice chromatin contains numerous interactions among DNA, RNA and protein to regulate critical biological processes in various aspects of rice life. We developed an effective method for mapping histone-mediated chromatin associated RNA-DNA interactions, followed by paired-end-tag sequencing (ChRD-PET) in rice. With H3K4me3 ChRD-PET, H3 ChRD-PET and RNase H treated H3K4me3 ChRD-PET, we present a highly comprehensive map of RNA and chromatin interactions around promoters in rice MH63. Through integrating ChIA-PET (published data), ChRD-PET and ssDRIP-seq data analysis, we demonstrated the function of RNAs-chromatin interactions in different level. We also conducted ATAC-seq and integrative analysis uncovered the relationship of epigenetic modifications and ChRD-PET interactions. Our findings firstly revealed the map and features of RNAs-chromatin interactions in rice.
Project description:We report Proximity Ligation Assisted ChIP-sequencing (PLAC-seq), a method for comprehensive detection of long-range interactions associated with proteins of interest. PLAC-seq requires up to 500-fold less starting material compared to ChIA-PET and using experimentally determined input as control precisely reveals protein associated interaction upto single-element resolution. Application of PLAC-seq to mouse embryonic stem cells revealed a comprehensive map of regulatory interactions.
Project description:We developed a novel approach, J-binding protein 1 sequencing (JBP1-seq), that combines the benefits of an improved recombinant JBP1 protein, Nextera-based library construction, and nextgeneration sequencing (NGS) for genome-wide profiling of 5-hydroxymethylcytosine (5hmC). Compared with the original JBP1, this new recombinant JBP1 was biotinylatedin vivo and conjugated to magnetic beads via biotin-streptavidin interactions. These modifications allowed a more efficient and consistent pull-down of β-glucosyl-5-hydroxymethylcytosine (β-glu-5hmC), and sequence-ready libraries can be generated within 4.5 hours from DNA inputs as low as 50 ng. 5hmC enrichment of human brain DNA using the new JBP1 resulted in over 25,000 peaks called, which is significantly higher than the 4,003 peaks enriched using the old JBP1. Comparison of the technical duplicates and validations with other platforms indicated the results are reproducible and reliable. Thus, JBP1-seq provides a fast, efficient, cost-effective method for accurate 5hmC genome-wide profiling. An improvement of JBP1-Seq