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 37degreesC, even in the presence of cycloheximide, gave decreasing function, as assessed at 23degreesC 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. Although the first two aims appear obtainable, the third was not in this example of the application, limiting its uses for some but not all purposes.