Figure 7.

t-KSRP destabilizes mRNAs transfected into HeLa cells. (A) HeLa cells were cotransfected with pEGFP-C2-UTR (containing the entire 3′-UTR of Pgk2) and vectors expressing t-KSRP or an N-truncated (cytoplasmic form) of PTBP2. Following actinomycin D addition, cells were collected at intervals, total RNAs were purified and mRNA levels were analyzed by northern blotting. β-Actin mRNA was used as a loading control. (B) The F3 subclone of the 3′-UTR of Pgk2 and β-actin mRNA were used as nonbinding RNA incubation and loading controls, respectively. The F3 RNA was used in place of the F1 RNA because it contained the same polyadenylation signal as the transcript from pEGFP-C2-UTR. Each assay was repeated at least three times with essentially identical results.