Figure 4.

Knockdown of NPM1 results in an increase in mRNA poly(A) tail length. Total RNA was isolated from untreated HeLa cells (HeLa lanes), HeLa cells containing a vector only control (LKO.1 lanes) or HeLa cells knocked down for NPM1 (NPM1 KD lanes) and analysed by linker ligation-mediated PCR-based poly(A) tail length assay. A set of samples was treated with oligo dT and RNAse H to remove the poly(A) tail before analysis (RNase H/d(T) lanes). The PAT lanes represent samples where mRNAs with intact poly(A) tails were analysed. Primers for β-actin mRNA were used in (A), hnRNP H mRNA in (B) and rps5 mRNA in (C). PCR products were analysed on a 5% acrylamide gel. The positions of the unadenylated RNA (A₀), normally polyadenylated (pA) and hyperadenylated (pA++) are indicated on the left.