Nucleotide sequence and organization of full length human U4 RNA pseudogenes

Two loci encoding human U4 RNA, designated U4/7 and U4/14, have been isolated and sequenced. Both are pseudogenes in that their sequences do not match any identified human U4 RNA species perfectly. The U4/7 locus harbours a full-length pseudogene of 144 bp with eight base substitutions in the structural region. This pseudogene might be derived from a hitherto unidentified human U4 RNA gene. The second locus, U4/14, has a complex structure; the structural sequence of a U4 gene has apparently been integrated into an Alu sequence.