The top genes: on the distance from transcript to function in yeast glycolysis.

With its abundant components and extensive study, the glycolytic pathway in the yeast Saccharomyces cerevisiae would appear ideal to obtain and reconcile the 'omes of transcript, protein, metabolite and flux. But to do so is challenging and, as is often the case, close correlation of gene expression and function is elusive, even in this organism.

Setting of graded levels of a protein in yeast by a t-degron technique as applied to phosphoglycerate mutase.

Background: Setting of graded levels of a protein for in vivo studies by controlled gene expression has inconveniences, and we here explore the use of the t-degron technique instead.

Results: In a yeast t-degron (ubiquitin-argDHFR(ts))- phosphoglycerate mutase (GPM1) fusion strain, increasing periods of exposure to the non-permissive temperature 37 degrees C, even in the presence of cycloheximide, gave decreasing function, as assessed at 23 degrees C in vivo by glucose metabolism and confirmed by immunoblot.

Conclusion: An ideal system would set a range of lower levels of a protein, do so without compensating protein synthesis, and give stable activity for in vitro comparisons.