Example of the plasmid shuffle test for the synthetic lethality between the substitution of PAB3 for Pab1p and mutations in various factors involved in mRNP biogenesis, processing, and export (see Table 1 for the full listing). The respective mutant strains (rna15-2, nup100Δ, gle2-1, and the wild-type control are shown) with their chromosomal PAB1 gene disrupted and the functional copy of PAB1 provided on CEN/URA3 plasmid, were transformed with either centromeric or high-copy (2 μ) plasmid-bearing pGAL-PAB3 cassette, as indicated at left. Transformants were grown in synthetic complete medium with uracil and dilution series plated onto galactose or glucose-based synthetic medium with 5-FOA to select for the cells that have lost the CEN/URA3/PAB1 plasmid. Only cells that grew on Gal/5-FOA, but not on Glu/5-FOA, resulted from complementation of the pab1 deletion by the pGAL-PAB3 expression cassette. Plating on the rich YPGal medium (to provide the total viable cell number) is also shown. All plates were grown for 6 d.
