Figure 1.

Stabilization of Ste6 through overproduction of gene products. (Left) Strain RKY901, which contains a chromosomal STE6-lacZ fusion, was transformed with multicopy plasmids carrying different genes. The transformants were tested for LacZ activity by a filter assay. LacZ activity is reflected in a dark blue color of the colonies. (Right) Ste6 half-life in strain JD52 transformed with the multicopy plasmids was determined by pulse-chase experiments. Cells were labeled with [³⁵S] Trans label for 15 min and were then chased with an excess of cold methionine and cysteine for the time intervals indicated. Ste6 was precipitated from cell extracts with polyclonal antibodies directed against Ste6. The transformed plasmids were YEplac181 (vector control) (A), pRK587 (2μ-MOS10) (B), pRK585 (2μ-SNF7) (C), pRK567 (2μ-VPS4) (D), and pRK586 (2μ-VPS35) (E). The calculated Ste6 half-lives are shown at the right side of the diagram.