biostudies-literatureKiethega GNCanadian Institutes of Health Research301-13https://www.ebi.ac.uk/biostudies/studies/S-EPMC3594288biostudies-literatureUnknown10(2)We previously reported a unique genome with systematically fragmented genes and gene pieces dispersed across numerous circular chromosomes, occurring in mitochondria of diplonemids. Genes are split into up to 12 short fragments (modules), which are separately transcribed and joined in a way that differs from known trans-splicing. Further, cox1 mRNA includes six non-encoded uridines indicating RNA editing. In the absence of recognizable cis-elements, we postulated that trans-splicing and RNA editing are directed by trans-acting molecules. Here, we provide insight into the post-transcriptional processes by investigating transcription, RNA processing, trans-splicing and RNA editing in cox1 and at a newly discovered site in cob. We show that module precursor transcripts are up to several thousRNA biologyRNA-level unscrambling of fragmented genes in Diplonema mitochondria.PMC3594288MOP-79309Kiethega GNTurcotte MBurger GYan YfalseRNA-level unscrambling of fragmented genes in Diplonema mitochondria.We previously reported a unique genome with systematically fragmented genes and gene pieces dispersed across numerous circular chromosomes, occurring in mitochondria of diplonemids. Genes are split into up to 12 short fragments (modules), which are separately transcribed and joined in a way that differs from known trans-splicing. Further, cox1 mRNA includes six non-encoded uridines indicating RNA editing. In the absence of recognizable cis-elements, we postulated that trans-splicing and RNA editing are directed by trans-acting molecules. Here, we provide insight into the post-transcriptional processes by investigating transcription, RNA processing, trans-splicing and RNA editing in cox1 and at a newly discovered site in cob. We show that module precursor transcripts are up to several thous2013-01-01T00:00:00Z2013 Feb2026-04-30T23:32:53.797Z2026-04-07T16:28:12.935ZS-EPMC35942882332460310.4161/rna.23340