B2-like repetitive sequence from the X chromosome of the American mink (Mustela vison)

In analysis of the repeats from the mink X Chromosome (Chr), we have identified a B2-like repetitive sequence of 195 base pairs (bp) flanked by short direct repeats of 14 bp. It contains regions homologous to the split intragenic RNA polymerase III promoter and a 3' A-rich region followed by an oligo(dA) sequence. A feature of the repeat is the presence of a perfect polypyrimidine tract 22 bp in length absent from the known Alu- and Alu-like sequences. Alignment of the mink B2-like sequence and mouse B2-consensus sequence allowed us to estimate their similarity as 55%. The repeat is present in 1-2 x 10(5) copies per mink genome and 2-4 x 10(3) copies per X Chr. In situ hybridization analysis demonstrated a similar distribution pattern of the B2-like repeat along the length of all the mink chromosomes including the X. We also observed the presence of mink B2-like hybridizable sequence in the genomes of other Carnivora species.