Fig. 3

A modified reporter cassette – mneoM – minimizes splicing of human SVAs. a Sequence of the modified mneoM reporter cassette. The HSV TK polyA of mneoI is replaced by a minimal functional polyA signal (min pA). The resulting polyA signal leading to premature termination upstream of the reporter cassette (middle line, yellow box) is changed to AACAAA (boxed in green). The polyA signal facilitating 3′ end formation of the neomycin phosphotransferase (Neo) RNA is in red and underlined. Restriction sites used for cloning are italicized and underlined. b Northern blot analysis of mneoM-tagged human and orangutan SVA and LAVA RNAs. Expected sizes of the transcripts spliced in the reporter cassette only are: H8_43–4.1 kb; H19_27–3.3 kb; OU3–4.6 kb; OU4–4.7 kb; LAVA_F – 3.6 kb. Asterisks indicate unspliced transcripts; the arrow marks double-spliced mRNAs of the mneoM-tagged human SVAs. c Retrotransposition of mneoM-tagged human and orangutan SVAs and a gibbon LAVA element. Retrotransposition rates +/− SEM are shown relative to H8_43 (100%). H8_43; H19_27 – human SVA_E; OU3; OU4 – orangutan SVAs. Average colony counts are given on top of each column. n = 4