Fig. 3.

Functional significance of the intervening C and G nucleotides in the U-rich loop and A-rich tract. (A) A schematic diagram is shown for the ENE-like structures predicted to form by the putative MALAT1 ENE with a 3′-poly(A) tail (nucleotides 8263–8336) or its adjacent A-rich tract (nucleotodes 8263–8355). The blue, green, and orange boxes outline the nucleotides targeted for mutagenesis. (B) Northern blot analysis of β-globin and NeoR mRNAs (Upper) and quantitation (Lower) were performed as in Fig. 1C. Black denotes WT sequence; mutated nucleotides are red. The plus (+) and delta (Δ) symbols represent a nucleotide insertion and deletion, respectively. The WT βΔ1,2 reporter levels were set at an arbitrary value of 1 for the βΔ1,2-MALAT1 ENE WT (white bar, lane 2) and the βΔ1,2-MALAT1 ENE+A+mascRNA WT (gray bar, lane 6). Each mutant was normalized relative to its WT counterpart. Relative accumulation is the average of at least three independent experiments; error bars represent SD.