PAX3-FOXO1 escapes miR-495 regulation during muscle differentiation.
Pax3 plays an essential role in myogenesis. Previously, we found a tumor-signature chimeric fusion RNA, PAX3-FOXO1 also present during muscle differentiation, raising the possibility of its physiological role. Here we demonstrated that the fusion is needed transiently for muscle lineage commitment. Interestingly, the fusion ortholog was not found in seven mouse muscle differentiation/regeneration systems, nor in other stem cell differentiation systems of another three mammal species. We noticed that Pax3 is expressed at a much lower level in human stem cells, and during muscle differentiation than in other mammals. Given the fact that the fusion and the parental Pax3 share common downstream targets, we reasoned that forming the fusion may be a mechanism for human cells to escape certain microRNA regulation on Pax3. By sequence comparison, we identified 16 candidate microRNAs that may specifically target the human PAX3 3'UTR. We used a luciferase reporter assay, examined the microRNAs expression, and conducted mutagenesis on the reporters, as well as a CRISPR/Cas9 mediated editing on the endogenous allele. Finally, we identified miR-495 as a microRNA that specifically targets human PAX3. Examining several other fusion RNAs revealed that the human-specificity is not limited to PAX3-FOXO1. Based on these observations, we conclude that PAX3-FOXO1 fusion RNA is absent in mouse, or other mammals we tested, the fusion RNA is a mechanism to escape microRNA, miR-495 regulation in humans, and that it is not the only human-specific fusion RNA.
['Xie|Zhongqiu|Z|', 'Tang|Yue|Y|', 'Su|Xiaohu|X|', 'Cao|Junwei|J|', 'Zhang|Yanru|Y|', 'Li|Hui|H|']
D000818:Animals D064113:CRISPR-Cas Systems D002454:Cell Differentiation D045744:Cell Line, Tumor D000071161:Forkhead Box Protein O1 D000072669:Gene Editing D005786:Gene Expression Regulation D055785:Gene Knockdown Techniques D017930:Genes, Reporter D006736:Horses D006801:Humans D051379:Mice D035683:MicroRNAs D024510:Muscle Development D000072041:PAX3 Transcription Factor D034622:RNA Interference D034741:RNA, Small Interfering D012756:Sheep D013552:Swine
miR-495 myogenesis microRNA Chimeric RNA adipose-derived stroma/stem cells mesenchymal stem cells