Host range of strand-biased circularizing integrative elements: a new class of mobile DNA elements nesting in Gammaproteobacteria

Table 1 Features of five prokaryotic DNA transposon groups encoding tyrosine recombinases

	ICEs/IMEs	SEs	GInts^c	RITs^d	Tn554-related elements^e
Hosts	Archaea Bacteria	Gammaproteobacteria	Gammaproteobacteria Betaproteobacteria	Bacteria	Staphylococcus Enterococcus
Proteins involved in recombination	Int, Xis	IntA, Tfp, IntB, Srap	GinA, GinB, GinC, GinD	RitA, RitB, RitC	TnpA, TnpB, TnpC
Target site specificity^a	+	+	+	NT	+
Empty site^b	+	−	±	NT	NT
Movement	Cut-out paste-in (excision integration)	Copy-out copy-in?	NT	NT	NT

^a+ : The presence of target site specificity. NT: not formally tested by experiments
^b+ : attL × attR recombination produces empty site. -: attL × attR recombination does not produce empty site. ± : some members do not produce empty site
^cBardaji et al. [23] mentioned the presence of GInts in taxa other than Proteobacteria. However, the discovery rate is unknown
^dThe RIT elements (RITs) comprise three coding regions encoding tyrosine recombinase and 34 bp terminal inverted repeats [24,25,26]. Three recombinases of archetype RIT element in Cupriavidus metallidurans CH34 (NC_007973.1; locus_tags Rmet_1271, Rmet_1272, Rmet_1273) are 315 to 410 aa long in size, and all possess catalytic tyrosine
^eThe host range of Tn554-related elements and whether Tn554-related elements generate empty sites have not formally been investigated. TnpC is the Srap/GinD counterpart according to structure prediction

ISSN: 1759-8753