Consistent levels of A-to-I RNA editing across individuals in coding sequences and non-conserved Alu repeats

Background: Adenosine to inosine (A-to-I) RNA-editing is an essential post-transcriptional mechanism that occurs in numerous sites in the human transcriptome, mainly within Alu repeats. It has been shown to have consistent levels of editing across individuals in a few targets in the human brain and altered in several human pathologies. However, the variability across human individuals of editing levels in other tissues has not been studied so far. Results: Here, we analyzed 32 skin samples, looking at A-to-I editing level in three genes within coding sequences and in the Alu repeats of six different genes. We observed highly consistent editing levels across different individuals as well as across tissues, not only in coding targets but, surprisingly, also in the non evolutionary conserved Alu repeats. Conclusions: Our findings suggest that A-to-I RNA-editing of Alu elements is a tightly regulated process and, as such, might have been recruited in the course of primate evolution for post-transcriptional regulatory mechanisms.