# Structural and functional studies of chromatin modifiers

> **NIH NIH R01** · ST. JUDE CHILDREN'S RESEARCH HOSPITAL · 2022 · $376,950

## Abstract

Summary
Regulation of genome expression is essential for cells to maintain their identity and loss of cell identity
leads to tumorigenesis. Cancer Genome Project has revealed that chromatin modifiers and
remodelers are highly mutated in human cancers, however, despite the importance of these factors,
we know little about their mechanisms of activity. To address this knowledge gap, we will combine
cryo-EM, biochemistry and genetics to determine how enzymes and structural proteins modify
nucleosome and chromatin structure.
Among the key players in the control of genome expression are histone modifications that, through
specific reader domains, recruit various protein complexes to chromatin. Histone lysine methylation is
a stable chromatin mark that is deposited by histone lysine methyltransferases (KMTs) and
methylation of different lysine residues has different outcomes on gene expression; H3K36
methylation is deposited over actively transcribed genes, whereas H3K9 methylation is a hallmark of
silent heterochromatin. Perturbations in KMT levels lead to aberrant genome expression and formation
of cancers cells, however, we do not understand how KMTs bind and modify nucleosome. H3K9
methylation and heterochromatin are required for deposition of centromere specific histone H3
variant CENP-A to chromatin, an epigenetic mark of centromeres. The centromere is the specialized
chromatin region on which kinetochores assemble to segregate chromosomes. Despite the
importance, structure of centromeric chromatin assembled on CENP-A nucleosome is still largely
unknown. Guided by the strong preliminary data, we propose to pursue three Specific Aims to
understand how KMTs bind and modify nucleosomes and to characterize centromeric chromatin. We
will combine cryo-EM with biochemistry and genetics to determine mechanisms of H3K36 (Aim 1)
and H3K9 (Aim 2) methylation. Moreover, we will use cryo-EM to visualize centromeric chromatin
assembled on CENP-A nucleosome (Aim 3).
Together, our proposed studies will have broad impact in chromatin field by showing how chromatin
proteins bind the nucleosome and how this interaction provides specificity for their activity. Our
long-term goals are to understand the regulation of genome expression by chromatin and discover
why mutations in chromatin proteins lead to the formation of cancer cells.

## Key facts

- **NIH application ID:** 10322987
- **Project number:** 5R01GM135599-03
- **Recipient organization:** ST. JUDE CHILDREN'S RESEARCH HOSPITAL
- **Principal Investigator:** Mario Halic
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $376,950
- **Award type:** 5
- **Project period:** 2020-01-01 → 2023-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10322987

## Citation

> US National Institutes of Health, RePORTER application 10322987, Structural and functional studies of chromatin modifiers (5R01GM135599-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10322987. Licensed CC0.

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