Figure: L1 retrotransposition cycleL1 mRNA (red) is exported into the cytoplasm, translated, and L1-encoded proteins (L1 ORF1p, L1 ORF2p) bind to their own mRNA (cis preference) and form ribonucleoprotein (RNP) complexes which are reimported into the nucleus. Subsequently, L1 RNA is reverse transcribed and the cDNA is inserted into the genome by a mechanism termed target-primed reverse transcription (TPRT). Frequently, reverse transcription fails to proceed to the 5’ end, resulting in truncated non-functional L1 de novo insertions.Source: PEI

http://www.pei.de/nn_156666/EN/research/research-groups/praesident-research-en/pr-retroelements-en/pr-retro1-en/pr-retro1-node-en.html?__nnn=true

http://www.schaft.net/n00bs/2008/05/13001554.html