Ty1 LTR-retrotransposon population in Saccharomyces cerevisiae genome: dynamics and sequence variations during mobility

• Published in: FEMS yeast research Vol. 11; no. 4; pp. 334 - 344
• Main Authors: Bleykasten-Grosshans, Claudine, Jung, Paul P, Fritsch, Emilie S, Potier, Serge, de Montigny, Jacky, Souciet, Jean-Luc
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.06.2011; Oxford University Press
• Subjects: DNA, Fungal - genetics; evolution; Genetic screening; Genetic Variation; Genome, Fungal; Genomes; Long terminal repeat; Mobility; Mutants; nonautonomous transposable element; nuclear genome; Nucleotide sequence; Recombination; Recombination, Genetic; Retroelements - genetics; Reverse Transcriptase Polymerase Chain Reaction; Reverse transcription; Saccharomyces cerevisiae; Saccharomyces cerevisiae - chemistry; Saccharomyces cerevisiae - cytology; Saccharomyces cerevisiae - genetics; screening; Sequence Alignment; Terminal Repeat Sequences - genetics; transposable element; transposable elements; Transposition; transposition (genetics); Transposons; Yeast; yeasts; nonautonomous transposable element; recombination; transposable element; reverse transcription
• ISSN: 1567-1356; 1567-1364
• DOI: 10.1111/j.1567-1364.2011.00721.x

Transposable element (TE) evolution in genomes has mostly been deduced from comparative genome analyses. TEs often account for a large proportion of the eukaryotic nuclear genome (up to 50%, depending on the species). Among the many existing genomic copies, only a small fraction may contribute to the mobility of a TE family. We have identified here, using a genetic screening procedure to trap Ty1 long terminal repeat-retrotransposon insertions in Saccharomyces cerevisiae, which among the populations of resident Ty1 copies are responsible for Ty1 mobility. Although the newly inserted Ty1 copies resulting from a single round of transposition were found to originate from a limited subset of Ty1 resident copies, they showed a high degree of diversity at the nucleotide level, mainly due to the reverse transcription-mediated recombination. In this process, highly expressed and strikingly nonautonomous mutant Ty1 were found to be the most frequently used resident copies, which suggests that nonautonomous elements play a key role in the dynamics of the Ty1 family.