Fig. 1. LINE and SINE transposition.
(A) Copy step of a LINE: L1 gene transcription by Pol II followed by L1 RNA translation. (B) Paste steps of L1 and Alu element transposition using the endonuclease (ENDO) and reverse transcriptase (RT) activities of ORF2p. (C) Copy step of a SINE: Alu element transcription by Pol III. (D) Intrachromosomal recombination between related LINEs or SINEs resulting in genomic deletion. (E) Interchromosomal recombination between related LINEs or SINEs resulting in genomic rearrangements.