Author/Editor		Župunski, Vera
Title		Strukturne in evolucijske analize Bov-B line elementov pri vretenčarjih
Type		monografija
Place		Ljubljana
Publisher		Medicinska fakulteta
Publication year		2001
Volume		str. 110
Language		slo
Abstract		Bov-B LINEs are non-LTR retrotransposons that transpose via an RNA intermediate in the genome and between genoms. Non-LTR retrotransposons are divided into 16 clades and Bov-B LINEs are members of the RTE clade. The distribution and evolutionary dynamics of the Bov-B LINE element and other non-LTR retrotransposons from the RTE clade have been examined. We have determined the sequence of the full-length Bov-B LINE from Vipera ammodytes, the first full-lenght retrotransposon from the RTE clade in Squamata to be reported. The element has a structural organisation typical of the RTE clade of non-LTR retrotransposons. The distribution of Bov-B LINEs in vertebrates and invertebrates was examined by amplification of a major part of the open reading frame ORF2, which encodes two crucial enzymes for retrotransposition. Bov-B LINEs are present in squamates, wallaby (Macropus) and ruminants. Intraspecies and interspecies variability was very low. An unusually high level of sequence conservation (83 %) also exists between the evolutionarily older snakes and Ruminantia. The distribution of the RTE retrotransposons was examined by searching a number of databases. The RTE clade has been found to be much more widely distributed than previously thought, and novel representatives have been discovered in plants, brown algae, annelids, crustaceans, mollusks, echinoderms and teleost fishes including the full-length RTE elements, Bov-B/RTE from Bombyx mori and Strongylocentrotus, plant RTE and Oryzias RTE. They all have the conserved structural organisation of the RTE clade. Analysis of their sequences has shown that Bov-B LINEs originated in invertebrates, from which the element was transmitted horizontally to the reptiles. In squamates, amplification and vertical transmission has been observed. In the genome of the long-nosed viper some active copies of the Bov-B LINE may still be present. (Abstract truncated at 2000 characters).
Descriptors		DNA INSERTION ELEMENTS VERTEBRATES EVOLUTION, MOLECULAR VIPERIDAE BASE SEQUENCE CLONING, MOLECULAR POLYMERASE CHAIN REACTION TRANSFECTION BACTERIOPHAGES ESCHERICHIA COLI AMINO ACID SEQUENCE PHYLOGENY