Related Experiment Video
Updated: Aug 10, 2026
08:21
Site-specific Bacterial Chromosome Engineering: ΦC31 Integrase Mediated Cassette Exchange (IMCE)
Published on: March 16, 2012
Integration host factor interacts with the DNA replication enhancer of filamentous phage f1
D Greenstein1, N D Zinder, K Horiuchi
1Rockefeller University, New York, NY 10021.
Summary
The Escherichia coli integration host factor (IHF) activates phage f1 DNA replication by binding to the replication enhancer sequence. This binding is crucial for efficient phage replication and F-pili expression.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- Phage f1 infection relies on F-pili, whose expression is regulated by Escherichia coli integration host factor (IHF).
- Bacterial strains lacking IHF exhibit poor phage f1 infectivity.
Purpose of the Study:
- To investigate the role of IHF in phage f1 DNA replication.
- To identify the specific binding sites and mechanism of IHF action in phage f1 replication.
Main Methods:
- Gel retardation assays to determine IHF binding to the origin of replication.
- DNase I footprinting to map IHF binding sites within the replication enhancer.
- Genetic analysis using IHF mutants and initiator protein mutations.
Main Results:
- Phage f1 DNA replication is significantly reduced (3% of wild-type) in IHF mutant bacteria.
- IHF specifically binds to multiple sites within the phage f1 replication enhancer sequence.
- Mutations in initiator protein (gene II) suppress the replication defect in IHF mutants.
Conclusions:
- IHF acts as an activator of phage f1 DNA replication.
- The replication enhancer sequence is the primary site of IHF action.
- IHF's role in replication is distinct from its role in F-pili expression.
More Related Videos
10:18Generation of Plasmid Vectors Expressing FLAG-tagged Proteins Under the Regulation of Human Elongation Factor-1α Promoter Using Gibson Assembly
Published on: February 9, 2015
10:41Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation
Published on: January 4, 2017
Related Concept Videos
00:43Lysogenic 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...
01:32Replication in Prokaryotes
DNA replication has three main steps: initiation, elongation, and termination. Replication in prokaryotes begins when initiator proteins bind to the single origin of replication (ori) on the cell's circular chromosome. Replication then proceeds around the entire circle of the chromosome in each direction from the two replication forks, resulting in two DNA molecules.
Many Proteins Work Together to Replicate the Chromosome
Replication is coordinated and carried out by a host of specialized...
Many Proteins Work Together to Replicate the Chromosome
Replication is coordinated and carried out by a host of specialized...
01:28Fimbriae, Pili, and Axial Filaments
Fimbriae and pili are specialized bacterial surface structures that play pivotal roles in adhesion, genetic exchange, and motility. Composed primarily of pilin protein, these hairlike appendages are crucial for bacterial survival and pathogenicity in various environments.Fimbriae: Adhesion and PathogenicityFimbriae are fine, filamentous structures measuring 2–10 nanometers in diameter and are densely distributed on the bacterial cell surface. They facilitate bacterial adhesion to abiotic...
01:19Conjugation
Conjugation is a form of horizontal gene transfer that primarily occurs in bacteria and some archaea, promoting genetic diversity and adaptation. Bacteria can acquire resistance genes through conjugative plasmids, allowing them to survive antibiotic treatments that would otherwise be lethal. This process involves direct contact between cells through specialized structures such as the sex pilus and is mediated by conjugative plasmids, including the F (fertility) factor.Conjugation requires...
01:19Mechanism of Conjugation
Bacterial conjugation is a mechanism of horizontal gene transfer that enables the exchange of genetic material between bacterial cells through direct contact. This process is facilitated by a donor cell carrying a conjugative plasmid, which encodes genes necessary for pilus formation, DNA replication, and transfer. The conjugative plasmid plays a central role in initiating and executing the transfer of genetic material.The tra region of the conjugative plasmid encodes proteins responsible for...
01:26DNA 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...