Preparation of a mRNA-dependent cell-free translation system from whole cells of Saccharomyces cerevisiae.

A cell-free protein-synthesizing system has been prepared from Saccharomyces cerevisiae by mechanical breakage of cells, isolation of a 30000 x g supernatant fraction and removal of endogenous mRNA by treatment with micrococcal nuclease. The system thus isolated is dependent on added mRNA and translates yeast mRNA to discrete products, many of then identical with yeast proteins synthesized in vivo. Activity and properties of this system are comparable to those of other eukaryotic cell-free translation systems. It offers the following advantages, compared to yeast translation systems described previously. (a) Its isolation is simple and fast. (b) Since it is not isolated from spheroplasts there is no danger of its inactivation by contaminants in enzymes used for spheroplast preparation. (c) Isolation appears to be less strain-dependent and can be carried out starting from cells in various physiological states.