title: Integrative and Conjugative Elements (ICEs): What They Do and How They Work.
abstract: Horizontal gene transfer plays a major role in microbial evolution, allowing microbes to acquire new genes and phenotypes. Integrative and conjugative elements (ICEs, a.k.a. conjugative transposons) are modular mobile genetic elements integrated into a host genome and are passively propagated during chromosomal replication and cell division. Induction of ICE gene expression leads to excision, production of the conserved conjugation machinery (a type IV secretion system), and the potential to transfer DNA to appropriate recipients. ICEs typically contain cargo genes that are not usually related to the ICE life cycle and that confer phenotypes to host cells. We summarize the life cycle and discovery of ICEs, some of the regulatory mechanisms, and how the types of cargo have influenced our view of ICEs. We discuss how ICEs can acquire new cargo genes and describe challenges to the field and various perspectives on ICE biology.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; email: adg@mit.edu , john5771@umn.edu.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Johnson
authors.forename: Alan D
authors.initials: AD
authors.lastname: Grossman
mesh_terms: D003227:Conjugation, Genetic; D004261:DNA Replication; D004251:DNA Transposable Elements / Q000502:physiology*; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005786:Gene Expression Regulation; D022761:Gene Transfer, Horizontal; D010957:Plasmids; D011995:Recombination, Genetic
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial
keywords: ICE; ICEBs1; Tn916; bacteria; conjugation; gene transfer