Figure 4.

Frequent occurrence of a G nucleotide upstream of L1-mediated HERV-W pseudogenes. The underlined sequence at the top is the previously reported HERV-W LTR consensus sequence, also termed LTR17. Previously reported HERV-W full-length pseudogenes (Costas 2002; Pavlicek et al. 2002a) are exemplified. GenBank accession nos. harboring the respective pseudogenes are listed on the right. Target site duplications (TSD) were determined visually and are indicated on the left. Note that an additional G nucleotide is present in position nucleotide -1 that is not present in the LTR consensus sequence, and that is not found in LTR17 variants in the human genome, supporting reverse transcription of a CAP structure by the L1 retrotransposition machinery.