Fig. 4

SMN-C5 binds to the SMN2 ESE2 and the STRN3 “ESE-like” structure. a Schematic illustration of the ESE2 region in the SMN2 exon 7, and the putative ESE in the STRN3 exon 8 (indicated in pink). Note that the 5′ss of these two exons are identical (in blue). b Direct binding analysis on a SPR system (Biacore 2000) to investigate the interaction between SMN-C5 or NVS-SM1 (10 µM each) and buffer control, to the immobilized ESE2 RNA in the SMN2 gene. Representative sensorgrams from triplicate experiments are depicted. c Quantitative assessment of binding of SMN-C5 and NVS-SM1 (10 µM each) to distinct RNAs in the SMN2 gene (ESE1, ESE2, ESE3, ESE3_TLS2, antisense_TLS2, Exon 7, ISS-N2, I7_TSTL4/6, I7_c, I7_TSL7, “GA” motif, and “GU” motif) immobilized on the SPR sensor. RNAs were captured via biotin on the streptavidin-coated sensor at surface densities in the range of 900–1200 RUs (response units). The SPR signals monitored for small molecules are normalized to the molecular mass. 100% binding corresponds to the amplitude of SPR signal monitored for binding of a small molecule to the RNA strand by full occupancy of one binding site (1:1 binding stoichiometry). d Binding to the STRN3 ESE-like region. Data in c and d represent means ± SEM of five replicates