Targeted DMS probing of SF3A3 5' UTR

To delineate the native structure of SF3A3 5'UTR, RNA was harvested from IMR90 human fibroblasts. Using specific primers and DMS-MaPSeq pipeline, we validated individual base pairing probabilities within the endogenous 5'UTR of SF3A3 (samples described as 'in vivo' transcribed). DMS-MaP-Seq  is based on the principle that DMS is highly reactive to solvent-accessible, unpaired adenine (A) and cytosine (C) residues, but remains inert toward base-paired A and C engaged in Watson-Crick interactions (Rouskin et al., 2014). Using this methodology, we identify stable stem-loop structure (SL3) positioned within SF3A3 5'UTR. To further validate the functional importance of SL3, the structural point mutant (SF3A3 5'UTR mut: A55C and U95A) and rescue (SF3A3 5'UTR res: A55C and U95A and rescuing point mutations G61U and U100G) sequences of SF3A3 5'UTR were cloned into the reporter plasmid. For the validation of these mutate-and-rescue constructs, plasmids were in vitro transcribed and either used directly (samples described as 'in vitro')  for DMS-MaP-Seq probing. 2 replicates for IMR90 RNA (2 specific primers for SF3A3 5'UTR) and 3 experiments for SF3A3 5'UTR WT, SF3A3 5'UTR mut, SF3A3 5'UTR res cloned into the plasmids