Characterization and occurrence of two repeated palindromic DNA elements of Brucella spp.: Bru-RS1 and Bru-RS2.

Two repeated DNA elements of 103 bp and 105 bp were discovered in brucellae and designated Bru-RS1 and Bru-RS2, respectively. The two elements are palindromic, are 65% similar in sequence, form two families of elements that are slightly divergent in sequence, appear to be intergenic, and are found, collectively, in more than 35 copies in brucellae. These elements are bounded by perfect or nearly perfect inverted repeats. A third copy of the terminal repeat is found within the elements and is the terminus for several truncated copies of the Bru-RS1 family. Hybridization patterns for the elements among brucellae were unique. The elements are dispersed, highly conserved among brucellae, and hot-spots for insertion by IS711.