Yeast Saccharomyces cerevisiae is one of the best understood eukaryotic model organisms. It is used for research of various biological processes like gene expression, cell cycle, and metabolism, as well as for virus research [1,2]. ScV-LA is a dsRNA yeast virus belonging to Totiviridae family. The extracellular phase of this virus is unknown; in addition, virus does not interfere with cell growth [3]. Another endogenous elements of yeast are mobile genetic elements – transposons. Six families of transposons Ty1-Ty5 and Ty3p belonging to LTR-retrotransposons are found in yeast [4,5]. Transposons can impact the integrity of the genome, alter the expression of adjacent genes, or cause gross chromosomal rearrangements [6]. Basing on transcriptomic and proteomic data, the hypothesis was raised that ScV-LA virus may influence transposition efficiency. In order to assess the influence of ScV-LA on the transposition rate, the classical transposition test was updated by design of new fluorescence-based transposition rate assay, suitable for wild type yeast strains to be addressed.
In this study, the new transposition assay was developed and applied practically. The control experiment demonstrated that S. cerevisiae cells expressing GFP can be separated from non-fluorescent cells. The experimental plasmid, containing Ty1 transposon sequence and fluorescent reporter gene, was constructed and used to test transposition efficiency in laboratory yeast strains. Furthermore, suitable method to fix yeast cells prior to flow cytometry was selected and sufficient time of transposition induction was determined. The new transposition assay based on fluorescence will be used to study the interplay between ScV-LA virus and Ty1 transposition in S. cerevisiae.