# Post-initiation control of Pseudomonas aeruginosa exopolysaccharide biosynthesis operons

> **NIH AI R21** · OHIO STATE UNIVERSITY · 2026 · $439,094

## Abstract

SUMMARY
Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen that causes acute and chronic
pneumonia, sepsis, urinary tract infections, and surgical-site infections. Its success as a human pathogen
is due in large part to its ability to form biofilms, which confer resistance to the host immune system,
antibiotics, and other stresses. Biofilms are structured communities held together by an extracellular matrix
composed primarily of exopolysaccharides (EPS) encoded in long operons. As all RNA polymerases are
prone to premature termination, the expression of long operons commonly relies on dedicated
antitermination factors that belong to the universally conserved family of NusG transcription regulators.
NusG paralogs bind to the elongating RNA polymerase and enable uninterrupted synthesis of long RNAs
in many bacteria, including Bacillus velezensis, Bacteroidetes fragilis, and Escherichia coli. Surprisingly,
P. aeruginosa does not encode NusG paralogs, and the scarce available data suggest that its regulation
of transcription termination and antitermination is very different from that of E. coli. We hypothesize that
many extended P. aeruginosa operons are subject to premature termination by Rho, possibly with the
assistance of NusG and histone-like Mva proteins, and that they use unique antitermination mechanisms
to ensure complete synthesis of their multi-cistronic RNAs. We propose to investigate the regulation of P.
aeruginosa RNA chain elongation, focusing on two EPS operons, pel and psl. This choice is dictated by
outsized contributions of these gene clusters to P. aeruginosa pathogenesis and their expected
dependence on antitermination to complete the synthesis of 10-19 kb RNA chains. In Aim 1, we will
determine if Rho, NusG, and Mva proteins induce premature termination during transcription of the pel and
psl operons using in vivo RNA probing and in vitro assays with purified P. aeruginosa RNA polymerase
and transcription factors. In Aim 2, we will ident

## Key facts

- **NIH application ID:** 11288409
- **Project number:** 1R21AI196856-01
- **Recipient organization:** OHIO STATE UNIVERSITY
- **Principal Investigator:** IRINA  ARTSIMOVITCH
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** AI
- **Fiscal year:** 2026
- **Award amount:** $439,094
- **Award type:** 1
- **Project period:** 2026-04-01T00:00:00 → 2028-03-31T00:00:00

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11288409

## Citation

> US National Institutes of Health, RePORTER application 11288409, Post-initiation control of Pseudomonas aeruginosa exopolysaccharide biosynthesis operons (1R21AI196856-01). Retrieved via AI Analytics 2026-06-25 from https://api.ai-analytics.org/grant/nih/11288409. Licensed CC0.

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