# Molecular control of pluripotency in humans

> **NIH NIH R01** · UNIVERSITY OF GEORGIA · 2020 · $317,100

## Abstract

PROJECT DESCRIPTION
Despite significant progress in deciphering the regulation of pluripotency in mouse models, there remain fun-
damental gaps in our understanding of how human (h)ESCs maintain the pluripotent state Our long-term goal
is to decipher the architecture of the regulatory network that allows for unrestricted hESC proliferation while
preserving their potential to form the full repertoire of cell types found in the human body. To comprehensively
identify genes involved in pluripotency maintenance we have conducted genome-wide shRNA screens in
hESC and begun in-depth analyses of the most significant hits. We focused on BCOR, a component of the
non-canonical Polycomb repressive complex 1.1 (PRC1.1) with a strong loss-of-pluripotency phenotype con-
sistently observed in multiple hESC lines. BCOR depletion in hESCs led to a loss of repressive chromatin at
key developmental loci and initiation of differentiation. We found that BCOR defines a novel subtype of the
PRC1 complexes with distinct recruitment and repression mechanisms. This novel BCOR-PRC1.1 complex
complements previously described KDM2B-PRC1.1 complex to efficiently silence differentiation programs in
hESCs. Our central hypothesis, formulated based on the preliminary data and prior work in mouse and human
ESCs, is that Polycomb repression of developmental regulators is established through combined action of the
KDM2B-PRC1.1 and the BCOR-PRC1.1 complexes. KDM2B mediates PRC1.1 recruitment to accessible CpG
islands while BCOR is responsible for the recruitment to dense chromatin, confers additional repressor function
and facilitates the deposition of H3K27me3 at target loci. In Aim 1, we will define the mechanisms of targeting
and repression by the non-canonical PRC1.1 complexes: (1A) Identify accessory factors and/or epigenetic
marks required for BCOR-mediated PRC1.1 targeting; (1B) Determine how local chromatin structure affects
the targeting of BCOR-PRC1.1 complexes. (1C) Define the repression mechanism mediated through the N-
terminus of BCOR, and (1D) Delineate specific roles of the KDM2B-PRC1.1 and the BCOR-PRC1.1 complex-
es in Polycomb domain assembly during the transition from naïve to primed pluripotent state. Furthermore, in
Aim 2, we will use our shRNA screen data to reconstruct the gene regulatory network that maintains primed
pluripotency in humans. We will employ CRISPR-i technology to knock-down 130 transcription factors whose
depletion leads to a loss of pluripotency. We will use single cell RNA-sequencing and our novel computational
tools, MAGIC and PHATE, to infer regulatory gene modules from perturbations. We will use ChIP-Seq to de-
fine genomic footprints of the key regulatory modules and integrate these data with hESC epigenetic map to
discover novel mechanisms of transcriptional control. Our approach is innovative, because we utilize novel
state-of-art technologies to obtain new insights into the regulatory complexity of hESCs. The proposed re-
search is sig...

## Key facts

- **NIH application ID:** 10020987
- **Project number:** 5R01GM107092-06
- **Recipient organization:** UNIVERSITY OF GEORGIA
- **Principal Investigator:** Natalia B Ivanova
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $317,100
- **Award type:** 5
- **Project period:** 2014-05-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10020987

## Citation

> US National Institutes of Health, RePORTER application 10020987, Molecular control of pluripotency in humans (5R01GM107092-06). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10020987. Licensed CC0.

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