# Gene positioning and dynamic chromatin organization of the human genome

> **NIH NIH R35** · OHIO STATE UNIVERSITY · 2024 · $382,960

## Abstract

Project Summary
The nuclear package that comprises the eukaryotic genome not only stores genetic information but also
mediates cell-type-specific gene expression. The hierarchical genome organization is tightly regulated to
precisely control cell functions. Interphase chromosomes occupy distinct nuclear spaces, a conserved genome
architecture known as chromosome territories. Technological advances over the last two decades have revealed
many new aspects of the three-dimensional architecture of the genome. However, understanding the
mechanisms that localize and mobilize chromosomal loci and territories in the nucleus requires high-resolution
studies in real time under physiological conditions. In the past five years, we have developed CRISPR-based
high-resolution live-cell imaging techniques using multiple colors to localize and track up to seven genomic loci
simultaneously. Recently, we have replaced fluorescent proteins with small cell-permeable RNA-interacting
molecules that improve brightness and reduce the size of tags by >100-fold. Our preliminary data revealed
surprising dynamic and structural aspects of the chromatin: (1) homologous and non-homologous chromosomal
loci moved at different speeds and in different directions; (2) large-scale chromosomal domains continuously
rearranged in minutes in non-stressed conditions, termed chromosome morphological dynamics; (3)
chromosome conformations were temperature-sensitive; and (4) transformed and non-transformed cells had
distinct chromosome conformations. In mouse embryonic stem cells, the mobility of promoters and enhancers
correlates with transcriptional activity for specific genes; however, how chromatin mobility correlates with
transcriptional activity is poorly understood and controversial. Building upon our preliminary results, we propose
to investigate four key concepts: (i) how chromosomal DNA is organized in individual chromosome territories, (ii)
what factors drive chromosome morphological dynamics, (iii) how active genes are positioned relative to non-
transcribed DNA regions to craft the landscape of the genome, and (iv) how chromatin movements correlate with
transcriptional activities in the nucleus. We will perturb transcription, temperature, and microtubule
polymerization to identify factors that govern chromosome dynamics. Integration of non-invasive imaging
approaches with biophysical models and RNA-seq data will provide new information on the mechanistic and
functional foundations of real-time chromatin dynamics and gene positioning at the single chromosome level in
the nucleus.

## Key facts

- **NIH application ID:** 10904942
- **Project number:** 5R35GM151095-02
- **Recipient organization:** OHIO STATE UNIVERSITY
- **Principal Investigator:** Li-Chun Tu
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $382,960
- **Award type:** 5
- **Project period:** 2023-08-15 → 2028-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10904942

## Citation

> US National Institutes of Health, RePORTER application 10904942, Gene positioning and dynamic chromatin organization of the human genome (5R35GM151095-02). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10904942. Licensed CC0.

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