Use of yeast genetic tools to define biological roles of novel protein phosphatases.

Regulatable gene expression is a powerful genetic tool for analyzing the function of a given gene product. The use of tetracycline-regulatable promoters in yeast represents a substantial improvement over previously described methods for gene regulation. Here we show how this approach can be used to analyze the biological role of serine/threonine phosphatase catalytic or putative regulatory subunits by constructing chromosomal or plasmid-borne conditional mutants. This is particularly useful given the large variety of important biological processes performed by these of enzymes, often necessaries for cell survival, which makes in some cases infeasible the generation of null mutants.