Figure 1

Assays of the transcriptional activity of the N domain of yeast valyl-tRNA synthetase. (A) Transcriptional assays. Various segments of the N domain of yeast ValRS were expressed as fusions to the specific DNA-binding protein, LexA, and the abilities of the resulting fusions to turn on the reporter genes (LEU2 and lacZ) which are controlled by distinct LexA-responsive promoters were tested. Activation of the reporter genes was indicated by the ability of the transformants to grow on selection medium lacking histidine, uracil, and leucine and to turn blue. (B) Quantitative assays of β-gal activity. (C) Western blot analysis of the expressions of LexA fusion proteins. Upper panel, LexA fusion protein; lower panel, phosphoglycerate kinase (PGK) (as a loading control). The numbers (circled) in A, B, and C represent the constructs shown in A.