Figure 6.
In vitro transcription analysis of wild type and B box-mutated Alu loci. In vitro transcription reactions were performed in HeLa nuclear extract using 0.5 μg of the indicated. Alu templates (lanes 5–10, 15–20, 25–30). A previously characterized Alu producing a 372-nt RNA (lanes 2, 12, 22) and a human tRNAVal gene producing a known transcript pattern due to heterogeneous transcription termination (lanes 3, 13, 23) (25) were used as positive controls for in vitro transcription and, at the same time, as a source of RNA size markers. Negative control reactions contained either empty pGEM®-T Easy vector (lanes 1, 11, 21) or no template DNA (no-template control (NTC), lanes 4, 14, 24). For each Alu, both the wild-type and a B box-mutated (Bmut) version were tested.