Determinants of LAVA mobilization efficiency are localized in the VNTR. (A) Schematic representation of the LAVA_E – LAVA_F chimeras tested. 5’ and 3’ domains of LAVA_E and LAVA_F were reciprocally exchanged at the Alu-like/VNTR junction and/or the VNTR/3’ part junction. Note that LAVA_F elements are characterized by a 3’ truncated Alu-like region. (B) Retrotransposition reporter assay following selection with G418. Cells were co-transfected with driver (pJM101 L1RP Δ Neo) and the respective mneoI-tagged chimeras or the LAVA_E/LAVA_F full-length constructs. Retrotransposition rates (+/− standard deviation, n = 3) are given relative to that of the full-length LAVA_F1 construct (100%). (C) Repeat unit (RU) schemata of the two LAVA elements tested. RU arrays corresponding to the respective subfamily consensus are highlighted in grey.