Inefficient expression of the DNA-binding domain of GAL4 in transgenic plants.

The DNA-binding domain of the yeast transcriptional activator GAL4 was expressed in transgenic tobacco plants in order to attempt to obtain specific repression of reporter genes. Expression of the GUS and the NPTII gene was essentially the same regardless of the presence of a gene encoding a functional GAL4 DNA-binding domain or the presence of GAL4 recognition sequences in the promoter region of the reporter genes. Despite high levels of GAL4 mRNA, no translation product was detectable in transgenic plants indicating that the failure to detect functional GAL4 in plants is due to the inefficiency of GAL4 mRNA translation in plants.