Overlapping Region of p53/Wrap53 Transcripts: Mutational Analysis and Sequence Similarity with microRNA-4732-5p


Background: Although the majority of investigations concerned with TP53 and its protein have focusedon coding regions, recently a set of studies highlighted significant roles of regulatory elements located in p53mRNA, especially 5´ UTR. The wrap53α transcript is one of those that acts as a natural antisense agent, formingRNA-RNA hybrids with p53 mRNA and protecting it from degradation. Materials and
Methods: In this study,we focused on the mutation status of exon 1α of the WRAP53 gene (according to exon 1 of p53) in 160 breasttumor tissue samples and conducted a bioinformatics search for probable miRNA binding site in the p53/wrap53overlapping region. Mutations were detected, using single stranded conformation polymorphism (SSCP) andsequencing. We applied the miRBase database for prediction of miRNAs which target overlapping region ofp53/wrap53 transcripts.
Results: Our results showed all samples to have wild type alleles in exon 1 of TP53gene. We could detect a novel and unreported intronic mutation (IVS1+56, G>C) outside overlapping regionsof p53/wrap53 genes in breast cancer tissues and also predict the presence of a binding site for miR-4732-5p inthe 5´ UTR of Wrap53 mRNA.
Conclusions: From our findings we propose designing further studies focusedon overexpression of miRNA-4732-5p and introducing different mutations in the overlapping region of wrap53and p53 genes in order to study their effects on p53 and its ΔN isoform (Δ40p53) expression. The results mayprovide new pieces in the p53 targeting puzzle for cancer therapy.