Splicing with inverted order of exons occurs proximal to large introns

Abstract

Following our studies which showed that the a and [ exons of the chicken c-ets-1 gene are not conserved in the human homologue, we succeeded in identifying a novel human c-ets-1 transcript in which the normal order of exons is scrambled. By PCR and RNase protection assays, we demonstrated that while the order of exons is different from that in genomic DNA, splicing of these exons in aberrant order occurs in pairs and at the same conserved consensus splice sites used in the normally spliced transcript. The scrambled transcript is nonpolyadenylated and is expressed at much lower levels than the normal transcript. It is not the consequence of genomic rearrangement at the ets-1 locus nor is it due to the transcription of any ets-1 pseudogene. These results confirm previous observations of scrambled splicing.

Circular RNAs: Novel Regulators of Neuronal Development

“…The serendipitous discovery of circular transcripts generated from the gene deleted in colorectal cancer ( DCC ), which encodes a cell surface receptor for the guidance cue Netrin-1, demonstrated that circRNAs can actually originate from transcribed genes (Nigro et al, 1991). In the following years, circRNA isoforms derived from several other loci were found in cells, including from the ETS-1, Dystrophin and Cytochrome P-450 2C18 genes (Cocquerelle et al, 1992; Saad et al, 1992; Bailleul, 1996; Zaphiropoulos, 1997). Initially, these circRNAs were thought to be potentially pathogenic byproducts of aberrant splicing or ‘transcriptional/splicing noise’ and did not receive much attention.…”