Intrinsic Alu affects for RNA splicing in a minigene model

<i>Alu</i> elements are commonly located in the introns of primate genomes and, once transcribed, can alter splicing patterns. The insertion of an antisense <i>Alu</i> element into intron 9 was shown to enhance exon 10 skipping in a previously developed <i>ACAT1</i> minigene model including exon 9-exon 11. This study investigates two intrinsic original <i>Alu</i>s' role located in the intron in <i>ACAT1</i> sequence using the same minigene splicing system. The deletion of intrinsic full <i>Alu</i>Sx originally located in intron 10 resulted in intron 10 retention, whereas the partial <i>Alu</i>Jb or antisense <i>Alu</i>Sx in the same intron was not sufficient for this process. Even normal splicing transcript wasn't shown without intrinsic full <i>Alu</i>Sx. Exon skipping was induced under the condition in which the intronic splice out prior to. Also, exon skipping was required with two close <i>Alu</i> elements with inverse orientations such as head-to-head and tail-to-tail in our minigene model. Intron retention seems to have been affected by shortening of introns or deletion of <i>Alu</i>'s splicing regulatory elements. Either way, <i>Alus</i> are associated with human gene expression incorporating themself and adopting in the human genome splicing system.