Related Experiment Video

Updated: May 18, 2026

T4 Bacteriophage and E. coli Interaction in the Murine Intestine: A Prototypical Model for Studying Host-Bacteriophage Dynamics In Vivo
08:46

T4 Bacteriophage and E. coli Interaction in the Murine Intestine: A Prototypical Model for Studying Host-Bacteriophage Dynamics In Vivo

Published on: January 26, 2024

Staphylococcal pathogenicity island interference with helper phage reproduction is a paradigm of molecular parasitism

Geeta Ram1, John Chen, Krishan Kumar

  • 1Skirball Institute Program in Molecular Pathogenesis and Department of Microbiology, New York University Medical Center, New York, NY 10016, USA.

Proceedings of the National Academy of Sciences of the United States of America
|September 20, 2012
PubMed

Insights

Staphylococcal pathogenicity islands (SaPIs) are mobile genetic elements that spread genes and interfere with helper phage reproduction. They employ diverse strategies, including blocking phage DNA packaging and diverting virion proteins, to ensure their own propagation.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Staphylococcal pathogenicity islands (SaPIs) are widespread mobile genetic elements in Staphylococcus aureus and other Gram-positive bacteria.
  • SaPIs facilitate horizontal gene transfer and act as phage satellites, exploiting temperate helper phages for replication and spread.

Purpose of the Study:

  • To investigate the diverse strategies employed by SaPIs to interfere with helper phage reproduction.
  • To elucidate the evolutionary mechanisms underlying SaPI persistence and transferability.

Main Methods:

  • Analysis of SaPI-encoded proteins and their interactions with phage machinery.
  • Characterization of SaPI-mediated interference with phage DNA packaging and virion assembly.
  • Comparative genomics to identify conserved and unique interference strategies.

Main Results:

  • SaPIs utilize multiple, distinct strategies to inhibit helper phage replication, suggesting convergent evolution.
  • One novel strategy involves a SaPI-encoded protein that specifically blocks phage DNA packaging by interfering with the phage terminase small subunit.
  • Another strategy involves diverting phage virion proteins for the production of SaPI-specific particles, reducing phage yield.

Conclusions:

  • SaPIs have evolved sophisticated mechanisms to interfere with their helper phages, ensuring their own replication and spread.
  • These interference strategies, including blocking phage DNA packaging and redirecting virion proteins, are crucial for the evolutionary success of SaPIs.
  • Understanding these interactions provides insights into the dynamics of mobile genetic elements and horizontal gene transfer in bacteria.

More Related Videos

Phage Phenomics: Physiological Approaches to Characterize Novel Viral Proteins09:40

Phage Phenomics: Physiological Approaches to Characterize Novel Viral Proteins

Published on: June 11, 2015

Tractable Mammalian Cell Infections with Protozoan-primed Bacteria13:54

Tractable Mammalian Cell Infections with Protozoan-primed Bacteria

Published on: April 2, 2013

Related Concept Videos

Microbial Interactions: Parasitism01:22

Microbial Interactions: Parasitism

Parasitism is a form of microbial interaction in which parasitic microbes exploit a host organism for nutrients and shelter, often at the host's expense. Unlike mutualistic relationships, where both organisms benefit, parasitism benefits only the parasite and harms the host.Classification of ParasitesMicrobial parasites are broadly classified based on their location relative to the host.Ectoparasites remain on the host’s surface, such as the skin or outer tissues, drawing nutrients...
Viral Replication: Lysogenic Cycle01:16

Viral Replication: Lysogenic Cycle

The lysogenic cycle is a crucial viral replication strategy that allows bacteriophages to persist within host cells without immediately destroying them. This process is primarily observed in temperate phages, such as bacteriophage lambda (λ), which infects Escherichia coli. The cycle allows the viral genome to persist across bacterial generations while keeping host cells viable.Integration of the Viral GenomeUpon infection, bacteriophage lambda attaches to the bacterial surface and injects its...
Lysogenic Cycle of Bacteriophages00:43

Lysogenic Cycle of Bacteriophages

In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage. Some prophages can re-activate and enter the lytic cycle. This often occurs in response to a perturbation, such as DNA damage, but can also transpire in the absence of...
DNA Bacteriophages01:26

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
Regulation of Bacterial Virulence01:28

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
Lytic Cycle of Bacteriophages01:30

Lytic Cycle of Bacteriophages

Bacteriophages, also known as phages, are specialized viruses that infect bacteria. A key characteristic of phages is their distinctive “head-tail” morphology. A phage begins the infection process (i.e., lytic cycle) by attaching to the outside of a bacterial cell. Attachment is accomplished via proteins in the phage tail that bind to specific receptor proteins on the outer surface of the bacterium. The tail injects the phage’s DNA genome into the bacterial cytoplasm. In the lytic replication...