Integrating conjugative elements (ICEs) are bacterial mobile genetic elements that are found integrated in the chromosome of their host and transfer via conjugation. The SXT/R391 family of ICEs is widespread in γ‑proteobacteria related to Vibrio cholerae and contributes to the massive...

Mercury resistance transposons belong to diverse groups of mobile elements that differ in structural and functional traits. They are broadly distributed among many bacterial species residing in diverse environments such as ancient permafrost, mercury ore, pristine or contaminated soil and...

ICE Bs1 is an integrative and conjugative element (ICE) integrated in the trnS‑leu2 gene in Bacillus subtilis . Related to Tn 916 and ICE St1 , ICE Bs1 contains 25 putative genes and is a new model system for understanding Gram‑positive ICEs. Here, we review the molecular mechanisms...

Genomic islands are large DNA segments, present in most bacterial genome, that are acquired via horizontal gene transfer and contribute to the rapid bacterial evolution and adaptation of the host cell. Here we focus on the clc element (or ICE clc ), a 103‑kb genomic island first discovered...

Tn 1549 and closely related elements are largely responsible for VanB‑type resistance in enterococci. The presence on these elements of three functional modules involved in vancomycin resistance, transposition, and intercellular transfer is indicative of conjugative transposons. Their...

The Tn 4371 ICE (Integrative Conjugative Element) family refers to a group of mobile genetic elements with four modules containing genes involved in integration (via a tyrosine‑based site‑specific recombinase), maintenance/stability, accessory genes conferring a special phenotype to the...

Conjugative transposons were known for many years and were initially discovered for their capacity to disseminate antibiotic resistance genes. They were first named transposons even if they rely on phage-type integrases for their mobility and are now classified as Integrative and Conjugative...

Pathogenicity islands are large chromosomal regions that encode multiple virulence genes along with the genes required for site specific integration and excision from the host chromosome. Among Gamma‑Proteobacteria pathogens, PAIs are highly prevalent as measured by the presence of a...

The conjugative transposon Tn 916 was first discovered in the late 1970s and is, together with the related conjugative transposon Tn 1545 , the paradigm of a large family of related conjugative transposons known as the Tn 916 /Tn 1545 family, which are found in an extremely diverse range of...

Integrons include a site‑specific recombination system that can capture gene cassettes. Gene cassettes are the smallest known mobilizable units of DNA and normally only comprise a single gene and a recombination site essential for the site‑specific recombination event to occur. Although...

Transfer of mobile genetic elements between prokaryotes is limited by restriction‑modification systems. Restriction‑modification systems consist of a modification enzyme that epigenetically methylates a specific DNA sequence, and a restriction endonuclease (restriction enzyme) that cuts...

Introns and inteins compose a group of mobile genetic elements that are ubiquitous across the tree of life. This chapter describes these parasitic genetic elements, specifically group I introns, group II introns, and inteins. These genetic elements are spliced out of either RNA or proteins...

Integrated conjugative elements (ICEs), previously called conjugative transposons (CTns), are proving to be as widespread in bacteria as conjugative plasmids, and they are making a significant contribution to bacterial evolution. CTns carry a variety of accessory genes, such as antibiotic...

Staphylococcal cassette chromosome mec (SCC mec ) is a class of mobile genetic element SCC that carries the methicillin resistant determinant mecA . It is a mobile genetic element driven by site‑specific recombinase(s) designated as cassette chromosome recombinase ( ccr ). Although many...

Mobilisable elements are genetic entities such as genomic islands, plasmids and transposons that are capable of intercellular movement, but are not in themselves conjugative. These elements rely on co‑resident conjugative elements to provide in trans factors that facilitate their transfer to...

Tn7 is a bacterial DNA cut and paste transposon that is distinguished by its ability to use several different pathways for target selection.  It may insert into a single specific chromosomal site called attTn7 that provides a “safe haven”, insert preferentially into a conjugating...

Bacteroides spp organisms, the predominant commensal bacteria in the human gut have become increasingly resistant to many antibiotics. They are now also considered to be reservoirs of antibiotic resistance genes due to their capacity to harbor and disseminate these genes via mobile...

PSAM2 is a self‑transmissible integrative and replicative mobile genetic element isolated from Streptomyces ambofaciens . It belongs to the large family of Actinomycete integrative and conjugative elements (AICEs). These elements have the ability to mobilize chromosomal DNA regions and thus...