# Mechanisms of pathogenic gene activation by aberrant transcriptional hubs formed by mutant ENL

> **NIH NIH F31** · UNIVERSITY OF PENNSYLVANIA · 2024 · $48,974

## Abstract

PROJECT SUMMARY
Transcription is an essential and tightly regulated process that requires the coordination of many factors to
ensure proper gene expression. Current models of transcription are predicated on stable, hierarchical
interactions. These models have been challenged through recent developments in in vivo imaging, which have
revealed that many transcriptional regulatory proteins interact transiently with chromatin. Instead of relying on
stability, occupancy at target loci is achieved through more frequent interactions resulting from the formation of
high local-concentration assemblies within nuclei, called hubs. Little is known about the functional impacts of
hub formation on transcription, how hubs alter the kinetics of regulatory proteins and how hubs function in cancer,
human expansion repeat disease, and other diseases. Previous studies largely rely on the ectopic
overexpression of proteins of interest and qualitative assays to study hub function and there is a of lack of both
specific strategies to perturb hub formation/properties with a measurable functional output and application of
suitable technologies to look at protein kinetics in vivo. The goal of this project is to use oncogenic mutations
found in the chromatin reader protein, ENL, to elucidate the mechanisms by which hubs impact transcription.
ENL mutations are among the first examples of pathogenic mutations that result in aberrant hub formation.
Importantly, such hub formation is functionally required for hyper-activation of target genes. The high specificity
and gain-of-function nature of ENL mutations make them a powerful system to study both the mechanisms of
hub formation as well as how aberrant hubs contribute to human disease. I hypothesize that ENL mutant proteins
promote the clustering of multiple elements, both genomic and proteomic, to alter transcription at target loci. In
Aim 1, I will combine advanced imaging techniques, including single molecule tracking and live imaging of
transcription, to determine the effect of hub formation on the molecular kinetics of incorporated proteins and
transcription dynamics. In Aim 2, I will investigate the effect of hub formation on the spatial proximity of target
genes using DNA-FISH and live imaging to determine if hubs drive genome reorganization for coordinated
expression of target loci. Completion of this project will offer novel insights as to how pathogenic mutations result
in aberrant hub formation and affect transcriptional dynamics to drive disease. More broadly, this work will
advance our understanding of hub-mediated gene regulation, revealing the potential for novel therapeutic
strategies to target gene dysregulation in disease.

## Key facts

- **NIH application ID:** 10929997
- **Project number:** 5F31CA284714-02
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** Kaeli Marie Mathias
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $48,974
- **Award type:** 5
- **Project period:** 2023-09-01 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10929997

## Citation

> US National Institutes of Health, RePORTER application 10929997, Mechanisms of pathogenic gene activation by aberrant transcriptional hubs formed by mutant ENL (5F31CA284714-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10929997. Licensed CC0.

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