Primary structure of the goat beta-globin locus control region

Abstract

The goat beta-globin cluster is composed of a triplicated four-gene set. A locus control region (LCR) containing elements homologous to 5'DNase I hypersensitive sites (HS) 1, 2, and 3 of the human beta-globin LCR has been identified at the 5' end of this locus. We determined 10.2 kb of nucleotide sequence from the goat beta-globin locus control region. Self-comparison of this sequence by dot matrix analysis revealed the presence of six complete and three incomplete artiodactyl repeats. A novel repeated element, termed D repeat, was also identified. Southern blotting analysis demonstrated that these elements exist in the goat genome as a low to medium frequency interspersed repeat family. The absence of any other large region of self-homology (direct or inverted) in the goat LCR suggests that 5'HSs 1, 2, and 3 did not arise through duplication, but rather evolved independently. By comparing goat 5'HS 1 to those of human, rabbit, and mouse, we show a greater than 80% conservation in sequence between the four species. This level of evolutionary conservation suggests that 5'HS 1 plays an important role in the regulation of beta-globin loci.