# Structural basis for mobilization of S. aureus pathogenicity islands

> **NIH NIH R01** · UNIVERSITY OF ALABAMA AT BIRMINGHAM · 2020 · $478,791

## Abstract

PROJECT SUMMARY
Staphylococcus aureus is an opportunistic bacterial pathogen involved in severe infections in
humans. Most virulence determinants in S. aureus are carried on mobile genetic elements
(MGEs), such as plasmids, bacteriophages and genomic islands. Transduction by
bacteriophages (phages) represents the main mechanism by which MGEs are transmitted
horizontally in S. aureus. Among these MGEs are the S. aureus pathogenicity islands (SaPIs),
which carry genes encoding superantigen toxins and other virulence factors. SaPIs are normally
stably integrated into the host genome, but become mobilized at high frequency by specific
helper phages, resulting in packaging of the SaPI genomes into transducing particles made
from helper-encoded structural proteins. SaPIs have evolved the ability to sense the presence
of a lytic phage, exploit phage functions and interfere with phage multiplication, in order to
promote their own dissemination. SaPIs this play important roles in S. aureus evolution and
pathogenicity.
 The overall aim of the current project is to understand the structural basis for SaPI
mobilization, helper-SaPI specificity, and the factors involved in their spread and establishment.
Our specific aims are: (1) Determine the mechanism of SaPI-induced capsid size redirection; (2)
Understand the function of the phage baseplate in infection and host specificity; (3) Elucidate
the role of minor capsid protein gp44 in the lytic/lysogenic switch.
 These three aims focus on different aspects of the mobilization process and will be studied
by a combination of genetic, biochemical and structural methods. All three aims are based on a
solid premise set by our previous studies and extensive preliminary data. Upon completion of
these aims, we will have gained new insights into the process of capsid assembly and size
redirection, the infection and transfer process, the mechanisms by which SaPIs and their
virulence factors are transmitted and established in the bacterial population.

## Key facts

- **NIH application ID:** 9850192
- **Project number:** 5R01AI083255-11
- **Recipient organization:** UNIVERSITY OF ALABAMA AT BIRMINGHAM
- **Principal Investigator:** Terje Dokland
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $478,791
- **Award type:** 5
- **Project period:** 2009-09-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9850192

## Citation

> US National Institutes of Health, RePORTER application 9850192, Structural basis for mobilization of S. aureus pathogenicity islands (5R01AI083255-11). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9850192. Licensed CC0.

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