FIGURE 4.

hClp1 complements lethal mutations in plant tRNA ligase. Yeast trl1Δ p360-TRL1 (URA3 CEN) cells containing CEN TRP1 plasmids bearing lethal AtRNL alleles S701A (A) or D726A (B) were transformed with 2μ HIS3 plasmids bearing genes encoding either wild-type yCLP1, wild-type hCLP1, or hCLP1 kinase active site mutants K127A-S128A and D151A. Control cells were transformed with the empty 2μ HIS3 vector (negative control) or a CEN HIS3 plasmid expressing the wild-type kinase-CPD domain TRL1-(389-827) (positive control). Trp⁺ His⁺ transformants were selected at 30°C and then streaked on agar medium containing 0.75 mg/mL FOA. The plates were photographed after 4 d at 30°C.