SEQUENCE AND CHARACTERIZATION OF AN INSERTION-SEQUENCE, IS711, FROM BRUCELLA-OVIS

The nucleotide (nt) sequence of a previously discovered insertion in B rucella ovis was determined and found to have the hallmarks of an inse rtion sequence (IS). The element, designated IS711, of 842 bp, is simi lar in G + C content to that of the Brucella genome and is bounded by 20-bp imperfect inverted repeats (IR). The element appears to duplicat e the nt TA of a consensus target site, YTAR (R, purines; Y, pyrimidin es). When the complete nt sequence of four elements and 300 bp of the 3' ends of five other elements were compared to IS711 and to each othe r, minor nt sequence variations were found amongst most of them. Simil ar to several other transposable elements, IS711 has overlapping ORFs rather than one long ORF extending the length of the element. Even tho ugh only ten B. ovis IS711 elements were characterized, in three cases we found these elements flanked by either identical or similar nt seq uences. This suggests that some target sites are hot spots for inserti on and that some of the elements may be duplicated by mechanisms other than transposition. No DNA or protein database entries had an obvious resemblance to either IS711 or its deduced gene products.