Knockdown efficiency in MM cells.

<p>Knockdown of ERK2 in different MM cell lines after transfection with either a short-hairpin expression vector (pSU-ERK2) or the “corresponding” target sequence synthesised as 25 bp stealth siRNA (stERK2; see Methods and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0097443#pone.0097443-Chatterjee1" target="_blank">[21]</a>). At day 1 post-electroporation half of the transfected culture was subjected to the column purification method (also see Fig. 1b)–e)) (resp. cell sorting for AMO-1 cells) and the other half to debris removal only (also see Fig. 1f)). Cells were harvested for Western blotting at the times indicated. Empty pSUPER vector (pSU) transfected cells served as controls. The blots show that the ERK2 knockdown efficiency for stealth siRNA is virtually identical between cells that only underwent debris removal and those that were subjected to the column purification procedure. ERK2 knockdown using the short-hairpin expression vector was less efficient in debris-removal-only samples compared with their cognate column purification complements (see JJN-3, L-363). Representative experiments (JJN-3: n = 3; L-363: n = 2, AMO-1: n = 2) are shown. Anti-ERK1/2 antibody: CST.