The tandemly repeated U6 genes were isolated from the sea urchin Strongylocentrotus purpuratus. Each 1.8 kb repeat unit contains a single U6 RNA sequence. There are no sequence similarities between the U6 promoter and other sea urchin snRNA genes, other than a long polypyrimidine tract 3' of the U6 sequence.
Animals Caenorhabditis elegans