[Mobile ISCR elements: structure, functions, and role in the emergence, increasing and spreading of blocks of bacterial genes of multiple antibiotic resistance]

Abstract

The recently discovered method of horizontal distribution of bacterial genes with atypical ISCR sequences is reviewed using an example of drug resistance genes. The adjacent DNA segment mobilization is provided by the transposition of such elements, including rolling circle replication, formation of autonomous nonreplicable circular structures, and homological recombination. The gene distribution capacity with the ISCR elements is more significant than the capacity of transposons and integrons, thereby providing formation of groups of mobile genes, including antibiotic-resistance genes of pathogenic bacteria. The structure and functions of the ISCR elements were discussed together with their similarity and dissimilarity with the group of IS91-similar elements and their role in the emergence of blocks of bacterial genes encoding of multiple antibiotic resistance and their contribution to evolution of bacterial and plasmid genes.