# Role of putative cytotoxins in Chlamydia infection

> **NIH NIH R21** · UNIVERSITY OF KENTUCKY · 2024 · $215,453

## Abstract

ABSTRACT
 Chlamydia species are important pathogens that represent a paradigm for understanding
successful obligate intracellular parasitism. C. trachomatis is a prevalent human pathogens,
whereas C. muridarum is a murine-specific pathogen often used to study chlamydial disease in
a small animal model. Species-specific variability in coding capacity within the so-called
plasticity zone of the chlamydial chromosome is thought to be one source dictating differences
in infection biology. The presence/absence of genes encoding glycosyltransferases designated
as putative cytotoxins represents an intriguing example of this diversity. C. muridarum express
multiple homologous proteins that also show similarity to a family of larger cytotoxins. The
plasticity zone of common urogenital C. trachomatis serovars express a truncated protein while
ocular serovars of members of the lymphogranuloma venereum (LGV) biovar lack the toxin
genes completely. These cytotoxins have been proposed to mediate immediate toxicity in highly
infected epithelial cells by interfering with actin polymerization. Lack of tractable genetics in C,
muridarum and urogenital C. trachomatis, in particular has previously confounded definitive
studies, leading to a paucity in details regarding molecular mechanisms of infection. We have
overcome this barrier by deletion of putative cytotoxin genes in C. muridarum. Our data
indicated that these proteins were dispensable for immediate toxicity. Combined with analysis of
C. trachomatis CT166, our data implicate an alternative function for these proteins. We propose
to apply genetic and biochemical approaches to delineate molecular function(s) of these
putative glycosyltransferases and address their contribution(s) to species-specific infection
biology.

## Key facts

- **NIH application ID:** 10984199
- **Project number:** 1R21AI178108-01A1
- **Recipient organization:** UNIVERSITY OF KENTUCKY
- **Principal Investigator:** KENNETH A FIELDS
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $215,453
- **Award type:** 1
- **Project period:** 2024-08-21 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10984199

## Citation

> US National Institutes of Health, RePORTER application 10984199, Role of putative cytotoxins in Chlamydia infection (1R21AI178108-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10984199. Licensed CC0.

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