The 94th Annual Meeting of Japanese Society for Bacteriology

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4 Molecular Microbiology

[ODP4A] a. Genome, Plasmids, Horizontal Gene Transfer, Mobile Genetic Elements, and Evolution

[ODP-049] Retron structure of Vibrio mimicus and possibility of horizontal gene transfer

Toshi Shimamoto1, Yojiro Ishida2, Hirofumi Nariya3, ○Tadashi Shimamoto1 (1Food Microbiol. Hygiene, Grad. Sch. Integrated Sci. Life, Hiroshima Univ., 2St. Jude Chilren's Res. Hosp., 3Fac. Human Life, Jumonji Univ.)

Bacterial reverse transcriptase (RT) is an essential enzyme for the synthesis of a special RNA-DNA complex called msDNA. The genetic element required for the synthesis of msDNA is composed of msr-msd encoding the sequence of msDNA and the RT gene ret, and is called retron. Vibrio mimicus is closely related to V. cholerae and is known as the causative agent of food poisoning. The purpose of this study was to analyze the structure and function of V. mimicus retron-Vm85.
The genetic environment around retron-Vm85 of the V. mimicus CS30 strain was analyzed in detail, and comparative analysis was performed with the genomic sequences of other Vibrio species.
Analysis of the sequence of retron-Vm85 and its surroundings revealed that a 12-kb region containing retron, integrase genes and others sandwiched between direct repeats was inserted into the tRNA dihydrouridine synthase gene. A database search of the sequence of this region revealed that the strains of V. vulnificus and V. metoecus had a similar genetic region containing the retron. This result suggests that this 12-kb genetic region may be transferred between bacteria as a mobile genetic element. A similar genetic region was also found in the fish disease pathogen V. anguillarum, but interestingly, the retron was deleted. This suggests that the retron and the 12-kb genetic region may have been inserted in two steps.