YB-1 has a distinct role in dendritic cells, capable of enhancing IL-6 RNA stability.

<p>(<b>A</b>) Total RNAs were purified from culture medium or cell lysates from LPS-stimulated BMDCs expressing either control or YB-1 RNAi. The extracellular or intracellular IL-6 mRNA or TNF-α mRNA was examined by RT-PCR (primer pairs: P4 and P7 in <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112754#pone.0112754.s002" target="_blank">Table S1</a></b>). YB-1 knockdown and RNA quantitation were determined by RT-PCR using the indicated primers (primer pairs: P3 and P5). Arrowheads and arrows indicate pre-mRNA and mRNA, respectively. (<b>B</b>) Macrophages or dendritic cells were cotransfected with empty vector or YB-1-GFP together with IL-6 and a <i>Renilla</i> luciferase reporter gene and then stimulated with LPS for 12 h. Cell lysates were prepared and then measured by <i>Renilla</i>-Firefly luciferase dual assay. Luciferase activity was determined using a luminometer. All luciferase assays were performed in triplicate for each reporter construct. (<b>C</b>) The effect of YB-1 depletion on IL-6 mRNA stability in LPS-stimulated dendritic cells was assessed by RT-PCR analysis of IL-6 mRNA levels (primer pairs: P1 and P5). Total mRNA was isolated at different time points after ActD treatment. Each graph represents densitometric analysis of RT-PCR data. Relative densitometric values for each mRNA were corrected by dividing each value by that for the GAPDH mRNA in each blot. *<i>P</i><0.0005, ** <i>P</i><0.001, *** <i>P</i><0.005 (Student's t-test). Data are representative of three independent experiments.