Menin siRNA-silencing. MEN1 mRNA expression was analyzed in total RNA (1), siRNA negative control (2), siRNA-MEN1 (3). (4): no-RT; M, 100-base pair marker lane. Pre-miR-4258 expression after MEN1 mRNA silencing. 4258 pre-miR-RNA expression was analyzed in total RNA (1), siRNA negative control (2), siRNA-MEN1 (3). (4): no-RT.