Fig. 3

Evidence of circularity of Fmn RNA transcripts. An RT-PCR assay was used to assess the circularity of Fmn transcripts. (A) The relative locations of the primers used in this RT-PCR are shown in the schematic diagram of Fmn exon 4. Primer A was used to synthesize first-strand cDNA from wild-type murine adult brain and kidney RNA. The cDNA was amplified with the PCR primers B1 and B2, which face outward from exon 4. (B) Southern blot of RT-PCR products from brain and kidney cDNA and a negative control (described in Materials and Methods) hybridized with an exon 5 probe. (C) Schematic diagram of two circular RNA species represented by the subcloned and sequenced 402-bp and 340-bp RT-PCR products from this assay. Arrows represent the PCR primers B1 and B2, used in this assay. Numbers represent the complete Fmn exons, which were joined accurately at their consensus splice sites.