Fig. 4.

Functional complementation of Saccharomyces pgm1Δ/pgm2Δ double deletion mutant by Giardia phosphoglucomutases (Gl-PGM1 and Gl-PGM2). A Saccharomyces pgm1Δ/pgm2Δ double deletion mutant was transformed with pVV214 vector containing the full-length of Gl-PGM1 gene (top half of plate) or the Gl-PGM2 gene (bottom half of plate). Transformed yeasts were selected in synthetic medium-URA containing 2% glucose and then plated onto synthetic medium-URA supplemented with 2% (w/v) galactose (Gal) as the only carbon source (shown here). In the absence of a functional PGM, the Saccharomyces pgm1Δ/pgm2Δ double deletion mutant does not grow on Gal plates (data not shown). Before FOA treatment, both Giardia PGMs complement the Saccharomyces pgm1Δ/pgm2Δ double deletion mutant, so there is growth on Gal (left side of plate). After FOA treatment, which removes the plasmids containing the Giardia PGM genes, the Saccharomyces pgm1Δ/pgm2Δ cannot grow on Gal (right side of plate) but grow on Glc (data not shown)