# Regulation of chromosome inheritance and integrity

> **NIH NIH R35** · ROCKEFELLER UNIVERSITY · 2024 · $882,298

## Abstract

Project Summary
Chromosome inheritance during cell proliferation is fundamental for living systems. Failures in this process
cause diverse diseases, such as cancer. Through the development of various innovative methods and the
exploitation of the unique Xenopus egg extract cell free system, our research program studies structure,
function, and regulation of the nucleosome - the fundamental structural unit for chromosomal DNA - in
chromosome inheritance and integrity.
1) Roles of nucleosomes in mitotic chromosome structure, integrity and function. High resolution 3D structural
analysis of nucleoprotein complexes on functional chromosomes has been impossible. We propose to combine
an innovative cryo-EM method and nucleosome manipulation method that we developed in Xenopus egg
extracts to study how nucleosome dynamics and integrity are regulated on mitotic chromosomes.
2) Centromere-associated repeats and DNA methylation. Mutations in DNMT3B, ZBTB24, CDCA7, and HELLS
cause Immunodeficiency, Centromere instability and Facial anomalies (ICF) syndrome. We have demonstrated
that CDCA7 is a critical activator for the nucleosome remodeling by HELLS. Expression of HELLS, CDCA7 and
its paralog CDCA7L are linked to various cancers. While multiple roles of HELLS, including DNA methylation,
loading of macroH2A, and nonhomologous end joining (NHEJ), have been reported, it is not clear how CDCA7
contributes to these diverse processes and how they are related to immunodeficiency and cancers. We will
address this question through dissecting the molecular function of CDCA7 and HELLS.
3) Mitotic regulation of cGAS. cGAS is a critical innate immunity pattern receptor targeting pathogenic DNA.
cGAS binds to DNA and becomes activated to synthesize cyclic GMP-AMP (cGAMP). cGAMP activates
STING, which then triggers signal transduction pathway to promote inflammation. How does cGAS avoid being
activated by the host’s chromosomal DNA? We gave an answer to this question by demonstrating that the
nucleosome directly binds cGAS to block its DNA-dependent activation. However, when cGAS binds to
chromosomes during mitotic arrest, cGAS slowly becomes reactivated and induces apoptosis. Using Xenopus
egg extracts where we can precisely control nucleosome assembly, DNA, and cell cycle stages without being
confounded by downstream events, we will dissect the mechanism of mitotic suppression and reactivation of
cGAS.

## Key facts

- **NIH application ID:** 10842783
- **Project number:** 2R35GM132111-06
- **Recipient organization:** ROCKEFELLER UNIVERSITY
- **Principal Investigator:** Hironori Funabiki
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $882,298
- **Award type:** 2
- **Project period:** 2019-05-01 → 2029-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10842783

## Citation

> US National Institutes of Health, RePORTER application 10842783, Regulation of chromosome inheritance and integrity (2R35GM132111-06). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10842783. Licensed CC0.

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