Replicating function of the RS1 element associated with Vibrio cholerae CTX phi prophage

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• The Vibrio cholerae CTX phi prophage utilizes RS elements for integration.
• Understanding the replication mechanisms of these elements is crucial for studying cholera pathogenesis.

Purpose of the Study:

• To investigate the role of the RS1 element in autonomous replication.
• To identify the specific regions and factors involved in RS1-mediated replication.

Main Methods:

• Cloning of the RS1 element from Vibrio cholerae.
• Functional analysis of RS1 in a recA- E. coli strain (Peru-15).
• Site-specific integration assays and deletion analysis of the RS1 element.
• DNA sequence analysis to identify putative protein binding sites.

Main Results:

• RS1 promotes autonomous replication of a suicide vector in a recA- strain.
• A specific region within RS1, containing cis-acting elements, is essential for replication.
• A mutation in the rstR gene abolished replication in one strain but not another, suggesting chromosomal context dependency.
• Sequence analysis revealed potential host protein binding sites involved in plasmid replication.

Conclusions:

• RS1 contains a unique replicon distinct from RS2.
• This RS1 replicon may play a role in the replicative recombination events leading to CTX element amplification.
• The findings provide insights into the replication strategy of the Vibrio cholerae CTX prophage.