Unilateral ends-out gene targeting increases mistargeting through supporting extensive single-strand assimilation.

Ends-out gene targeting enables the swapping of endogenous alleles with exogenous ones through homologous recombination which bears great implications both fundamental and applicable. To address the recombination mechanism(s) behind it, an experimental system was designed to distinguish between a possible (but rarely active) unilateral and the expected bilateral targeting in the yeast Saccharomyces cerevisiae in which the proportions of the two alternative genetic outcomes are conceived to mirror the probabilities of the two scenarios. The quantitative analysis showed that the bilateral targeting was expectedly predominant.

Insertion orientation within the cassette affects gene-targeting success during ends-out recombination in the yeast Saccharomyces cerevisiae.

Gene-targeting is one of the most important molecular tools for genomic manipulations for research and industrial purposes. However, many factors influence targeting fidelity undermining the efforts for accurate, fast, and reliable construction of genetically modified yeast strains. Therefore, it is of great academic interest that we uncover as many as possible parameters affecting the recombination mechanisms that enable targeting.

Dominant Epistasis Between Two Quantitative Trait Loci Governing Sporulation Efficiency in Yeast .

Sporulation efficiency in the yeast is a well-established model for studying quantitative traits. A variety of genes and nucleotides causing different sporulation efficiencies in laboratory, as well as in wild strains, has already been extensively characterised (mainly by reciprocal hemizygosity analysis and nucleotide exchange methods). We applied a different strategy in order to analyze the variation in sporulation efficiency of laboratory yeast strains.

The Walker A motif mutation recA4159 abolishes the SOS response and recombination in a recA730 mutant of Escherichia coli.

In bacteria, the RecA protein forms recombinogenic filaments required for the SOS response and DNA recombination. In order to form a recombinogenic filament, wild type RecA needs to bind ATP and to interact with mediator proteins. The RecA730 protein is a mutant version of RecA with superior catalytic abilities, allowing filament formation without the help of mediator proteins.