Random right monomer mutations affect Alu retrotransposition capability. (A) Constructs of tagged Alu elements containing a randomly selected genomic AluSx right monomer with several mutations were evaluated by transient transfections in HeLa cells under exogenously supplied ORF2p conditions. The relative activity of these Alu elements is shown. The construct A30 that contains the consensus AluYa5 right monomer was designated as 100. (B) A Northern blot analysis of the steady-state level of poly(A) selected RNA from the constructs in the same order as A is shown. The unspliced (open arrowhead) and spliced (black arrow) neo-tagged Alu transcripts are indicated. The spliced Alu transcript from the variable length constructs were normalized to cyclophillin (C, loading control) and expressed relative to the A30 construct (designated as 1.00). The mean ± SD for the quantitation results for each construct are indicated below (n = 3).
