Link to Pubmed [PMID] – 37779558
Link to DOI – 10.1016/j.coisb.2023.100473
Curr Opin Syst Biol 2023 Dec; 36:100473
Most life forms harbor multiple, diverse mobile genetic elements (MGE) that widely differ in their rates and mechanisms of mobility. Recent findings on two classes of MGE in prokaryotes revealed a novel mechanism, RNA-guided transposition, where a transposon-encoded guide RNA directs the transposase to a unique site in the host genome. Tn7-like transposons, on multiple occasions, recruited CRISPR systems that lost the capacity to cleave target DNA and instead mediate RNA-guided transposition via CRISPR RNA. Conversely, the abundant transposon-associated, RNA-guided nucleases IscB and TnpB that appear to promote proliferation of IS200/IS605 and IS607 transposons were the likely evolutionary ancestors of type II and type V CRISPR systems, respectively. Thus, RNA-guided target recognition is a major biological phenomenon that connects MGE with host defense mechanisms. More RNA-guided defensive and MGE-associated functionalities are likely to be discovered.