Insertion with long target duplication: a mechanism for gene mobility suggested from comparison of two related bacterial genomes.
The complete genome sequences of two closely related organisms--two Helicobacter pylori strains--have recently become available. Comparison of these genomes at single base pair level has suggested the presence of a mechanism for bacterial gene mobility--insertion with long target duplications. This mechanism is formally similar to classical transposon insertion, but the duplication is much longer, often in the range of 100bp. Restriction and/or modification enzyme genes are often within or adjacent to the insertion. A similar process may have mediated insertion of the cag(+) pathogenicity island in H. pylori. A similar structure was identified in comparisons between Neisseria meningitidis and Neisseria gonorrhoeae genomes. We hypothesize that this mechanism, as well as two other types of polymorphism linked with restriction-modification genes (insertion accompanied by target deletion and a tripartite structure composed of substitution/inversion/deletion), have resulted from attack by restriction enzymes on the chromosome.
Nobusato
A
A
Institute of Medical Science, University of Tokyo, Shirokanedai, Tokyo 108-8639, Japan.
Uchiyama
I
I
Ohashi
S
S
Kobayashi
I
I
D001483:Base Sequence; D007446:Chromosome Inversion; D015280:DNA Restriction-Modification Enzymes / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics*; D014644:Genetic Variation; D016680:Genome, Bacterial; D016480:Helicobacter pylori / Q000201:enzymology / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009345:Neisseria meningitidis / Q000201:enzymology / Q000235:genetics; D011110:Polymorphism, Genetic; D017384:Sequence Deletion
D015280:DNA Restriction-Modification Enzymes; D004269:DNA, Bacterial