Effect of U1 AMO (antisense morpholino oligonucleotides) on translational landscape

U1 snRNP could protect eukaryotic pre-mRNAs from premature mRNA 3’ end processing at thousands of intronic polyadenylation sites (PASs), a phenomenon known as U1 snRNP telescripting, or U1 snRNP inhibition of intronic premature cleavage and polyadenylation (PCPA). An outstanding question in the field is if these U1-regulated truncated forms of pre-mRNAs could be exported to the cytoplasm and have the potential to be translated. It was previously shown that some of the intronic PCPAed products induced by Spliceostatin A, a splicing modulator, might be translated in cells using Ribo-seq analysis. Here we performed similar analysis to address the question that if thousands of U1-regulated PCPAed products have the potential to be translated in the cytoplasm.