# Single-molecule analysis of how birth and death of mRNAs are regulated inside a bacterial cell

> **NIH NIH R35** · UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN · 2022 · $386,727

## Abstract

Project Summary
Bacteria are everywhere around us, playing critical roles in our health and global ecosystems. Understanding
how bacteria thrive is extremely important in keeping our bodies and environments safe and healthy. Bacteria
can dynamically adapt to a wide array of conditions by modifying their gene expression program, for example,
by boosting the production of proteins necessary for survival and limiting the wasteful production of others.
The ultimate goal of my research is to gain an enriched understanding of bacterial gene regulation, thus I study
the very fundamental question of how transcription, translation, and mRNA degradation are performed and
regulated in physiological settings. Due to the absence of a nucleus in bacterial cells, these three processes
occur in the same cytoplasmic volume without clear separations. Therefore, the cellular mechanisms enabling
their coordination inside a single cell offer an important foundation for understanding bacterial gene
expression programs. Here I describe projects in my group aiming to define the generalizable principles
underlying the spatiotemporal coordination of transcription, translation, and mRNA degradation in bacterial
cells. We plan to answer the following key questions: (1) What is the mechanism of transcription-translation
coupling? (2) How is the interaction between RNA polymerase (RNAP) and ribosome dynamically regulated?
(3) How is the rate of mRNA degradation regulated by the age of mRNA and the subcellular localization of
RNase E, the major ribonuclease for mRNA degradation in Escherichia coli? We will answer these questions by
imaging the dynamics of RNAP, ribosome, and RNase E at the single-molecule level in live cells. Combining
these techniques with bacterial genetics, we will identify factors that can modulate the dynamics of RNAP-
ribosome interactions and analyze the subcellular heterogeneity in the localization and function of RNase E.
Collectively, our work will uncover new mechanistic principles of bacterial gene regulation and generate new
methods for measuring, controlling, and modeling gene expression dynamics at the single-molecule level in
live cells. The findings from our work have potential applications for a broad range of human health issues,
such as promoting healthy microbiomes, killing pathogens, and improving industrial processes to reduce
pollution.

## Key facts

- **NIH application ID:** 10451617
- **Project number:** 5R35GM143203-02
- **Recipient organization:** UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
- **Principal Investigator:** Sangjin Kim
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $386,727
- **Award type:** 5
- **Project period:** 2021-08-01 → 2026-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10451617

## Citation

> US National Institutes of Health, RePORTER application 10451617, Single-molecule analysis of how birth and death of mRNAs are regulated inside a bacterial cell (5R35GM143203-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10451617. Licensed CC0.

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