Fig. 2

Validation of the existence and expression of circHNRNPU in IgD MM. A Illustration of the annotated genomic region of HNRNPU, the putative different RNA splicing forms and the validation strategy for circular exon 2 to 13 (circHNRNPU). Convergent (blue) and divergent (red) primers were designed to amplify the linear or back-splicing products. B-C RNA levels of circHNRNPU and linear HNRNPU ± RNase R were determined by RT-PCR and qRT-PCR. D Sanger sequencing following PCR was conducted using the indicated divergent flanking primers confirmed the “head-to-tail” splicing of circHNRNPU in ARP1 and CAG cells. E Relative RNA levels of circHNRNPU and HNRNPU in different time points. F BaseScope probe was applied for detecting circHNRNPU expression in healthy controls, IgG and IgD MM patients. G-H The levels of circHNRNPU in IgD patients were superior than IgG patients and normal control (NP) evaluated by RNA scope analysis, and the representative staining images were shown with positive reactions indicated by red arrows. I CircHNRNPU levels were significantly elevated in MM patients. J Elevation of circHNRNPU was associated with inferior EFS survival. The data are presented as mean ± SD.*p < 0.05, **p < 0.01, ***p < 0.001