# Late developmental regulation in Chlamydia

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA-IRVINE · 2020 · $449,858

## Abstract

Project Summary/Abstract
Chlamydia is one of the most important infectious agents from a public health
perspective. In 2014 more than 1.4 million cases of chlamydial infections were reported
to the CDC making it the most commonly reported infectious disease in the U.S.
Chlamydia causes an unusual intracellular infection in which there are two specialized
forms of the bacterium within an infected cell. The reticulate body (RB) is an intracellular
form that replicates via multiple rounds of binary fission. Then at a late stage in the
intracellular infection, each RB asynchronously converts into an elementary body (EB),
which is the infectious form that transmits the infection to a new cell. We propose to
study how this late developmental change from an RB to an EB is regulated by focusing
on a small group of chlamydial genes that are upregulated at late times in the infection.
We have evidence that these late genes are negatively regulated to prevent their
premature expression. In Aim 1, we will study a transcriptional regulator called EUO to
understand how its repression of late genes is relieved at late times to allow these genes
to be expressed. We hypothesize that EUO is converted in a redox-dependent manner
from a dimer into a monomer that is then degraded by proteolysis. In Aim 2, we will
study another regulator called RsbW, which we propose is part of a signaling pathway
that controls the transcription of a subset of late genes by σ28 RNA polymerase in
response to glucose availability. Aim 3 will use confocal microscopy to examine these
mechanisms of late gene regulation in individual RBs and EBs within a single infected
cell. We will investigate whether the regulators of late gene expression also control RB-
to-EB conversion and why this critical conversion step occurs asynchronously. These
studies have the potential to lead to novel therapeutic strategies for treating chlamydial
infections by interrupting this critical conversion step and preventing the production of
infectious bacteria.

## Key facts

- **NIH application ID:** 9978694
- **Project number:** 5R01AI123998-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA-IRVINE
- **Principal Investigator:** Ming Tan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $449,858
- **Award type:** 5
- **Project period:** 2017-08-01 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9978694

## Citation

> US National Institutes of Health, RePORTER application 9978694, Late developmental regulation in Chlamydia (5R01AI123998-04). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/9978694. Licensed CC0.

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