Figure 1.

Translational inactivation of the ndhB gene in the pSSH1 plastid transformation plasmid. The pSSH1 plasmid insert spans the first 732 bp of the ndhB gene. An additional C-G bp was introduced into codon 206 of ndhB by oligonucleotide-directed mutagenesis. The resulting plasmid was called pSSH1M. This additional nucleotide generated a diagnostic SmaI site and, in addition to a frame shift, all three stop codons (only two of which are shown). A 300-bp portion of the ndhB coding region (identical in tobacco and nightshade) adjacent to the HindIII cloning site is shown as it appears in IR_A (5′–3′ direction, strand A), from position 143,798 in the tobacco plastid genome. Selected restriction enzyme sites are also shown.