Nucleotide sequence and characterization of the traABCD region of IncI1 plasmid R64

A 3.6Kb BglII-SmaI segment of the transfer site of the IncI1 plasmid R64 drd-11 was sequenced and defined to study bacterial conjugation, the process by which plasmid DNA is transferred from cell to cell by direct contact. The DNA sequences were analyzed and revealed the presence of four genes, traA, traB, traC and traD, in this area. TraB, traC and traD genes were studied using maxicell experiments and traA gene was analyzed by developing a traA-lacZ fusion gene. Temporary mutations were introduced into the four genes to reveal that the traB and traC genes were necessary for the conjugal transfers in liquid and solid mediums.