A fast and efficient translational control system for conditional expression of yeast genes

A new artificial regulatory system for essential genes in yeast is described. It prevents translation of target mRNAs upon tetracycline (tc) binding to aptamers introduced into their 5'UTRs. Exploiting direct RNA–ligand interaction renders auxiliary protein factors unnecessary. Therefore, our approach is strain independent and not susceptible to interferences by heterologous expressed regulatory proteins. We use a simple PCR-based strategy, which allows easy tagging of any target gene and the level of gene expression can be adjusted due to various tc aptamer-regulated promoters. As proof of concept, five differently expressed genes were targeted, two of which could not be regulated previously. In all cases, adding tc completely prevented growth and, as shown for Nop14p, rapidly abolished de novo protein synthesis providing a powerful tool for conditional regulation of yeast gene expression

FISH as a tool to investigate chromosome behaviour in budding yeast.

Fluorescence in situ hybridization (FISH) provides an effective means to delineate chromosomes and their subregions during all stages of the cell cycle. This makes FISH particularly useful for studying chromosome behavior in species with minute genomes and/or poor chromosome condensation at metaphase, which is the case in model organisms such as the budding yeast Saccharomyces cerevisiae. Since its introduction in 1992, FISH with composite whole chromosome or locus specific probes has become an indispensable tool in the analysis of chromosome behavior in metaphase and interphase cells, and especially of meiotic chromosome pairing of wild-type and mutant yeast strains