title: Hominoid composite non-LTR retrotransposons-variety, assembly, evolution, and structural determinants of mobilization.
abstract: SVA (SINE-R-VNTR-Alu) elements constitute the youngest family of composite non-LTR retrotransposons in hominoid primates. The sequence of their assembly, however, remains unclear. Recently, a second family of VNTR-containing composites, LAVA (L1-Alu-VNTR-Alu), has been identified in gibbons. We now report the existence of two additional VNTR composite families, PVA (PTGR2-VNTR-Alu) and FVA (FRAM-VNTR-Alu), in the genome of Nomascus leucogenys. Like LAVA, they share the 5'-Alu-like region and VNTR with SVA, but differ at their 3'-ends. The 3'-end of PVA comprises part of the PTGR2 gene, whereas FVA is characterized by the presence of a partial FRAM element in its 3'-domain. Splicing could be identified as the mechanism of acquisition of the variant 3'-ends in all four families of VNTR composites. SVAs have been shown to be mobilized by the L1 protein machinery in trans. A critical role in this process has been ascribed to their 5'-hexameric repeat/ Alu-like region. The Alu-like region displays specific features in each of the VNTR composite families/subfamilies with characteristic deletions found in the evolutionary younger subfamilies. Using reciprocal exchanges between SVA_E and PVA/FVA elements, we demonstrate that the structure, not the presence of the (CCCTCT)n/ Alu-like region determines mobilization capacity. Combination of LAVA and SVA_E domains does not yield any active elements-suggesting the use of different combinations of host factors for the two major groups of VNTR composites. Finally, we demonstrate that the LAVA 3'-L1ME5 fragment attenuates mobilization capacity.
authors.affiliation: Institute for Interdisciplinary Research in Bio-Nano-Sciences, Molecular Biology Center, Babes-Bolyai-University, Cluj-Napoca, Romania.
authors.forename: Bianca
authors.initials: B
authors.lastname: Ianc
authors.affiliation: Institute for Interdisciplinary Research in Bio-Nano-Sciences, Molecular Biology Center, Babes-Bolyai-University, Cluj-Napoca, Romania.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Ochis
authors.affiliation: Wiesbaden, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Persch
authors.affiliation: Institute for Interdisciplinary Research in Bio-Nano-Sciences, Molecular Biology Center, Babes-Bolyai-University, Cluj-Napoca, Romania Institute of Biology, Romanian Academy, Bucharest, Romania.
authors.forename: Octavian
authors.initials: O
authors.lastname: Popescu
authors.affiliation: Institute for Interdisciplinary Research in Bio-Nano-Sciences, Molecular Biology Center, Babes-Bolyai-University, Cluj-Napoca, Romania annette.damert@gmx.de.
authors.forename: Annette
authors.initials: A
authors.lastname: Damert
mesh_terms: D020087:Alu Elements; D000818:Animals; D001483:Base Sequence; D019143:Evolution, Molecular; D016678:Genome; D006922:Hylobates / Q000235:genetics*; D018598:Minisatellite Repeats; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
keywords: Nomascus leucogenys; SVA; VNTR; retrotransposon