The genome of the Pseudomonas aeruginosa generalized transducing bacteriophage F116

Area of Science:

• Virology
• Microbiology
• Genomics

Background:

• F116 is a temperate, generalized transducing phage within the Podoviridae family, known to infect Pseudomonas aeruginosa.
• Previous understanding suggested F116 as a non-integrating phage, persisting as a plasmid during lysogeny.

Purpose of the Study:

• To characterize the genome and proteome of the F116 phage.
• To identify novel genes and understand the structural components of F116.
• To investigate the life cycle and genetic makeup of this Pseudomonas phage.

Main Methods:

• Genome sequencing and analysis to identify open reading frames (ORFs).
• Homology searches against known phage and bacterial genomic databases.
• One-dimensional SDS-PAGE and MALDI-TOF Mass Spectrometry for proteomic analysis.

Main Results:

• The F116 genome is 65,195 bp, dsDNA, with a GC content of 63.2%, encoding 70 putative ORFs.
• Only 16 ORFs showed significant similarity to known Pseudomonas or phage genes, indicating a large proportion of novel genes.
• A putative integrase (int) gene was identified, contrary to previous non-integrating assumptions. The major capsid protein was identified and shown to undergo posttranslational cleavage.

Conclusions:

• The F116 phage possesses a unique genome with numerous uncharacterized genes, expanding our knowledge of phage diversity.
• The identification of a putative integrase gene suggests a more complex lysogenic cycle than previously thought.
• Posttranslational modification of the major capsid protein provides new insights into F116 virion assembly and structure.