# The Biophysical and Molecular Mechanisms of Reliability in Development

> **NIH NIH R01** · PRINCETON UNIVERSITY · 2022 · $380,806

## Abstract

Project Summary
Metazoan development relies on precise and reproducible cell fate decisions. However, the molecular events
underlying these decisions, namely transcriptional activation of subsets of genes, are inherently stochastic. The
goal of the proposed study is to bridge this gap by uncovering how precise patterns emerge from dynamic gene
activation. Our past work was mostly focused on the readout of regulatory DNA sequences, such as enhancers,
controlling the activation of a target gene. However, during the previous funding cycle, we identified the functional
importance of the large chromosomal distances over which this regulation takes place, contributing to often rate-
limiting dynamics and adding an extra source for stochasticity. Numerous studies in the past decade have
pointed to the prevalence of such long-range chromosomal interactions adding another layer of complexity to
the regulation of gene expression. However, investigation of temporal dynamics of chromatin is strongly limited
by the prevalent use of bulk assays using fixed material, and traditional imaging methods often lack the
spatiotemporal resolution to accurately capture the dynamics of gene activity. Here we propose to overcome
these limitations by developing new imaging approaches and computational analyses to provide a dynamic
picture of chromosomal architecture and its causal relationship to transcription. For this purpose, we will
capitalize on the advantages of the early Drosophila embryo for the development of quantitative live imaging
methods. In this system, changes in segmentation gene expression are position-specific determinants of cell-
type identity. We will thus examine regulatory interactions at scales characteristic to flies and mammals (from
tens to hundreds of kilobases) and their implications in the context of cellular specification in a developing
organism. The proposed studies will help understand how robust cell type specification emerges from the
stochastic gene expression that is regulated by long-range interactions and chromatin architecture. The following
three complementary hypotheses are tested: 1) distinct locus-specific architectures generate different functional
outputs; 2) physical order underlies long-distance chromosomal relationships; 3) a functional relationship exists
between chromatin dynamics and activity. The overall goal of this project is to establish a quantitative link
between chromatin architecture and transcriptional activity, which will ultimately lead us to regulate and re-
engineer transcriptional programs underlying development and disease processes.

## Key facts

- **NIH application ID:** 10443605
- **Project number:** 5R01GM097275-12
- **Recipient organization:** PRINCETON UNIVERSITY
- **Principal Investigator:** Thomas Gregor
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $380,806
- **Award type:** 5
- **Project period:** 2011-07-21 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10443605

## Citation

> US National Institutes of Health, RePORTER application 10443605, The Biophysical and Molecular Mechanisms of Reliability in Development (5R01GM097275-12). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10443605. Licensed CC0.

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