An integration-proficient int mutant of bacteriophage lambda.

Area of Science:

• Molecular Biology
• Genetics
• Virology

Background:

• Bacteriophage lambda integrates into the bacterial genome via site-specific recombination.
• The int protein mediates this recombination by binding to specific DNA sequences called attachment sites.
• Understanding int protein function is crucial for studying viral integration and genome dynamics.

Purpose of the Study:

• To isolate and characterize a novel mutant int protein of phage lambda.
• To investigate the effects of this mutant on recombination between various attachment sites.
• To elucidate the role of int protein binding site distribution in recombination specificity.

Main Methods:

• Isolation and characterization of a novel int mutant of phage lambda.
• Assaying recombination frequencies between different attachment site pairs (phage-bacteria, phage-phage, prophage-prophage).
• Analyzing the distribution of int protein binding sites on different attachment sites.

Main Results:

• The novel int mutant efficiently promotes recombination between phage and bacterial attachment sites (attP-attB).
• This mutant shows poor recombination efficiency between other attachment site pairs, including phage-phage and prophage-prophage.
• Wild-type int protein also exhibits some discrimination among attachment site pairs.

Conclusions:

• The mutant int protein's phenotype is attributed to altered interactions dependent on the distribution of int protein binding sites.
• The mutant protein likely requires a specific arrangement of binding sites, characteristic of the attP-attB pair, for efficient activity.
• This suggests that int protein binding site distribution plays a key role in modulating recombination specificity in phage lambda.