mRNA with a <20-nt poly(A) tail imparted by the poly(A)-limiting element is translated as efficiently in vivo as long poly(A) mRNA

Impact of the PLE on translation of mRNA transfected into cultured cells. (A) mRNAs shown in Table 1 were transfected together with Renilla luciferase mRNA into LM(tk–) cells. Extracts prepared 1 h after transfection were analyzed for luciferase activity as in Figure 4, with the results for capped A0 control mRNA arbitrarily set to 1. The bars represent the mean ± SD for triplicate determinations. (B) RNA extracted from RNA-transfected cells was analyzed as in Figure 1 by Northern blot using a mixed probe for firefly (Fluc) and Renilla (Rluc) luciferase mRNA.