Crystallographic and X-ray scattering study of RdfS, a recombination directionality factor from an integrative and conjugative element.

The recombination directionality factors from Mesorhizobium spp. (RdfS) are involved in regulating the excision and transfer of integrative and conjugative elements. Here, solution small-angle X-ray scattering, and crystallization and preliminary structure solution of RdfS from Mesorhizobium japonicum R7A are presented.

An epigenetic switch activates bacterial quorum sensing and horizontal transfer of an integrative and conjugative element.

Horizontal transfer of the integrative and conjugative element ICEMlSymR7A converts non-symbiotic Mesorhizobium spp. into nitrogen-fixing legume symbionts. Here, we discover subpopulations of Mesorhizobium japonicum R7A become epigenetically primed for quorum-sensing (QS) and QS-activated horizontal transfer.

Delineation of the integrase-attachment and origin-of-transfer regions of the symbiosis island ICEMlSym.

Integrative and conjugative elements (ICEs) are chromosomally-integrated mobile genetic elements that excise from their host chromosome and transfer to other bacteria via conjugation. ICEMlSym is the prototypical member of a large family of "symbiosis ICEs" which confer upon their hosts the ability to form a nitrogen-fixing symbiosis with a variety of legume species. Mesorhizobial symbiosis ICEs carry a common core of mobilisation genes required for integration, excision and conjugative transfer.

Sequential induction of three recombination directionality factors directs assembly of tripartite integrative and conjugative elements.

Tripartite integrative and conjugative elements (ICE3) are a novel form of ICE that exist as three separate DNA regions integrated within the genomes of Mesorhizobium spp. Prior to conjugative transfer the three ICE3 regions of M. ciceri WSM1271 ICEMcSym1271 combine and excise to form a single circular element.