Sequencing and Annotation of Bacteriophage J1 Genome and its Relationship with Prophage Like Elements Present in the Model Strain Lactobacillus casei BL23

MARIA EUGENIA DIETERLE; DEBORAH JACOBS-SERA; DANIEL RUSSELL; GRAHAM HATFULL ; MARIANA PIURI

San Francisco

Congreso; 112th General Meeting American Society for Microbiology; 2012

ASM

Phage J1 was originally isolated in 1965 from an abnormal fermentation of Yakult using Lactobacillus casei strain Shirota as starter. Since its isolation J1 has been well characterized but its genome sequence was not available.We have sequenced and annotated the complete genome of phage J1 using 454 Sequencing and DNA master program. Interesting features were revealed from the sequence. Even this phage was described as lytic we found a gene that codes for an integrase and a putative attP site indicating that this phage could have a lysogenic life cycle in the proper host. We have also found that 30% of the phage genome is present in the genome of the recently sequenced model strain Lactobacillus casei BL23. This result led us to search for the presence of prophage like elements (PLEs) in the genome of this bacterial strain. We found at least four PLEs and three of them seem to be complete and organized in the following modules: attL-lysogeny-DNA replication transcriptional regulation-DNA packaging-head-joining-tail-tail fiber-lysis module-attR.Using a PCR technique we were able to show the presence of the circularized form of three of these phages in a subpopulation of cells and obtained the sequence of the attP (in the phage) and attB sites in the genome.Several protocols were tested for induction of these prophages and its further characterization.