Fig. 6

RBMS2 promoted mRNA stability by directly binding to P21 mRNA 3′-UTR. The relative expression of P21 in RBMS2-overexpressing MCF-7 (a) and SUM-1315 (b) cell lines after treated with 5 μg/ml ActD for 0, 2, 4, 6, and 8 h. MCF-7 (c and d) and SUM-1315 (e and f) cell lysates were collected and immunoprecipitated with RBMS2 antibody or control IgG followed by PCR (c and e) and qRT–PCR (e and f) measuring transcript levels of P21 in the control or RBMS2-mRNA immunocomplexes. g Dual-luciferase reporter containing P21 3′-UTR region (left) and AREs mutant region were constructed (right). Relative luciferase activity of P21–3′- UTR or mutant ARE after co-transfection with RBMS2-overexpressing (RBMS2) or control vector (Ctrl) into MCF-7 (h) and SUM-1315 (i) cell lines. Firefly luciferase activity was measured and normalized to Renilla luciferase activity. ARE, AU-rich element