Figure 2.

AtNTF2a and AtNTF2b, but not AtNTL, can functionally replace yeast NTF2. Yeast cells deleted for the genomic copy of the essential NTF2 gene but maintained by an NTF2 genomic plasmid (see “Materials and Methods”) were transformed with plasmids expressing AtNTF2a, AtNTF2b, or AtNTL under the control of a Gal-inducible promoter. Cultures were grown to saturation, serially diluted, and spotted on control (left) or 5-FOA (right) plates to eliminate the NTF2 maintenance plasmid. The control plate indicates that similar numbers of cells were spotted for each sample. The 5-FOA plate, where each of the indicated plasmids constitutes the sole source of NTF2, shows that both AtNTF2a and AtNTF2b can function in vivo, as cells expressing these proteins grow as well as the control cells that express yNTF2. In contrast, AtNTL cannot function in place of yeast NTF2, as cells that express this plasmid show no growth (similar to the vector-only control).