The MIR886 gene is transcribed by Pol III. (A) UCSC Genome Browser view of the MIR886 microRNA. The visual peak files and the markings are as in the legend of Figure 3. (B) The sequence corresponding to the POLR3D peak region (on the minus strand) is shown with putative A and B boxes indicated (the underlined nucleotides fit the A and B box consensus defined in Supplemental Fig. S1A). The likely transcription start and termination sites, as determined by POLR3D occupancy and sequence, are indicated. (C) The MIR886 gene is transcribed by Pol III in vitro. The genomic fragment carrying the MIR886 locus was immobilized on beads and used as template for in vitro transcription as described in Supplemental material. Tagetin was added in the reactions shown in lanes 2 and 4. The control template was the Ad2 VAI gene. (D) Pre-MIR886 RNA can be detected by Northern blot in IMR90hTert cells. Lanes 1 and 2 show duplicate RNA preparations. The blot was probed with a complementary oligonucleotide corresponding to regions 49–69 and 93–112 of the microRNA gene MIR886.
