Effect of the SARS-CoV-2 Delta-associated G15U mutation on the s2m element dimerization and its interactions with miR-1307-3p

TBE (left) and TBM (right) gel nondenaturing electrophoresis analysis of the SARS-CoV-2 s2m reference and the s2m G15U. The two s2m elements were compared using Mg²⁺ dependence where 1 µM RNA was incubated in the presence of 1, 5, or 10 mM MgCl₂ for 1 h, then split between two gels—TBE which chelated the Mg²⁺ ions, and TBM that maintained the Mg content. In the TBE, both s2m elements prefer their monomeric (M) states (left, arrow 1). In TBM, the monomeric states are still preferred (right, arrows 1 and 1′). Different migration patterns may be observed due to different shapes of the s2ms, as described in the text. Arrows 2 and 3 indicate the KD and ED, respectively. Degradation products are noted with (*).