Tobacco nuclear genes for Photosystem I subunits, psaD, psaE and psaH share an octamer motif bound with nuclear proteins.

In Nicotiana sylvestris, nuclear-encoded photosystem I (PSI) genes, psaD, psaE and psaH, share an octamer motif bound with three phosphoproteins. This motif is not found in the chloroplast genome. From the view point of endosymbiont hypothesis, these results suggest that a set of ancient PSI genes acquired a common cis-element in the nucleus after they were transferred from the ancestral organelle.