Dataset Information

Locus-specific proteomics identification of OCT4 regulators

ABSTRACT: We set out to develop an unbiased, genome-wide method to screen for proteins that locate to the OCT4 proximal enhancer (PE) in hESCs; for this purpose, we developed an optimized locus-specific proteomics approach in hESCs. First, we designed TALEN (Transcription Activator-Like Effector Nuclease) constructs to target the sequences that are near the OCT4 PE, located in a region of DNaseI hypersensitivity. TALEN constructs with the highest cutting efficiency were chosen for locus-specific proteomics. We then made modifications to the original TALEN protein to transform it into a catalytically-dead TALE (dTALE) protein that is optimized for locus-specific proteomics in hESCs via three steps: 1) The nuclease-domain FokI at the C-terminus was replaced by a GFP (green fluorescence protein); 2) a 3X FLAG tag at the N-terminus was included for following pull-down analysis; 3) the existing CMV promoter was replaced with an EF1alpha promoter that has robust expression in hESCs. This dTALE protein could then be chemically crosslinked to the OCT4 locus together with all the other proteins that bind to the locus. We verified that dTALE protein binds to the targeted locus by chromatin immunoprecipitation (ChIP)-qPCR. Following crosslinking, chromatin was sheared, and all the associated proteins were immunoprecipitated using an anti-FLAG antibody. Immunoprecipitation pulled down the dTALE protein as well as other proteins and complexes that are also attached to that region. Crosslinking was then reversed, and the samples were subjected to mass spectrometry to enable generation of a list of proteins that potentially bind to OCT4 PE locus.

OTHER RELATED OMICS DATASETS IN: GSE118638

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture, Embryonic Stem Cell

SUBMITTER: Daniel Chelsky

LAB HEAD: Daniel Chelsky

PROVIDER: PXD010963 | Pride | 2019-01-07

REPOSITORIES: Pride

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Publications

A distinct isoform of ZNF207 controls self-renewal and pluripotency of human embryonic stem cells.

Fang Fang F Xia Ninuo N Angulo Benjamin B Carey Joseph J Cady Zackery Z Durruthy-Durruthy Jens J Bennett Theo T Sebastiano Vittorio V Reijo Pera Renee A RA

Nature communications 20181022 1

Self-renewal and pluripotency in human embryonic stem cells (hESCs) depends upon the function of a remarkably small number of master transcription factors (TFs) that include OCT4, SOX2, and NANOG. Endogenous factors that regulate and maintain the expression of master TFs in hESCs remain largely unknown and/or uncharacterized. Here, we use a genome-wide, proteomics approach to identify proteins associated with the OCT4 enhancer. We identify known OCT4 regulators, plus a subset of potential regula ...[more]

PMID: 30349051

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Project description:Here, we performed RNA-interactome capture (RIC) on nuclear fractions from human embryonic stem cells (hESCs). The poly(A)+ RNA-bound proteome was determined by UV light-mediated cross-linking (CL) of RNAs to proteins in living cells, followed by nuclei isolation, oligo(dT) purification of poly(A)-RNA-protein complexes, and mass spectrometry analysis of captured proteins. As a control, we applied a similar strategy to non-cross-linked (non-CL) samples. RIC was performed in four independent biological replicates. This data accompanies the manuscript: "Uncovering the RNA-binding protein landscape in the pluripotency network of human embryonic stem cells". Abstract: "Embryonic stem cell (ESC) self-renewal and cell-fate decisions are driven by a broad array of molecular signals. While transcriptional regulators have been extensively studied in human ESCs (hESCs), the extent to which RNA-binding proteins (RBPs) contribute to human pluripotency remains unclear. Here, we carry out a proteome-wide screen and identify 810 proteins that directly bind RNA in hESCs. We reveal that RBPs are preferentially expressed in hESCs and dynamically regulated during exit from pluripotency and early lineage specification. Moreover, we show that nearly 200 RBPs are affected by knockdown of OCT4, a master regulator of pluripotency, several dozen of which are directly bound by this factor. Intriguingly, over 20 percent of the proteins detected in our study are putative DNA- and RNA-binding proteins (DRBPs), among them key transcription factors (TFs). Using fluorescently labeled RNA and seCLIP (single-end enhanced crosslinking and immunoprecipitation) experiments, we discover that the pluripotency-associated STAT3 and OCT4 TFs interact with RNA in hESCs and confirm the direct binding of STAT3 to the conserved NORAD long-noncoding RNA. Taken together, our findings indicate that RBPs have a more widespread role in human pluripotency than previously appreciated, reinforcing the importance of post-transcriptional regulation in stem cell biology".

Dataset Information

Locus-specific proteomics identification of OCT4 regulators

Publications

A distinct isoform of ZNF207 controls self-renewal and pluripotency of human embryonic stem cells.

Similar Datasets

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