Extended Data Fig. 8: A proposed model for GMT island replicative transfer.
From: Gamma-Mobile-Trio systems are mobile elements rich in bacterial defensive and offensive tools
A yet-unknown event or process leads to the excision and circularization of one of the GMT island strands without the flanking inverted repeat sequences; base pairing between the inverted repeat sequences may play a role in the process. A complementary strand is polymerized, resulting in a double-stranded circular form of the GMT island. The GMT system proteins, which are required for the excision and circularization, possibly remain bound to the junction between the ends of the GMT island and mediate recognition of a naïve insertion site containing a specific inverted repeat sequence. The naïve insertion site is cleaved within the spacer sequence found between the inverted repeats, and the GMT island is inserted into the recipient site. In parallel, the cell replaces the excised strand in the donor DNA using the remaining strand as a template. This process results in two identical GMT islands.
