TRANSCRIPTIONAL CONTROL OF PLANT-STORAGE PROTEIN GENES

The accumulation of plant storage proteins is controlled primarily by the transcriptional activation of their genes. Two classes of storage proteins, the zygotic or seed-specific, and the somatic, such as tuber proteins, have been studied. Gene expression analysis in transgenic p lants has defined small regions of the promoters of such genes that ar e able to confer the appropriate patterns of expression. Protein-DNA i nteractions, both in vivo and in vitro, have revealed proteins that bi nd to regions implicated in expression, and these may be transcription factors. Promoter deletion analysis has determined the role of some o f these DNA-binding proteins, such as in determining tissue-specificit y or levels of expression. A common theme linking the expression of bo th classes of storage proteins is the involvement of metabolite levels in directly controlling gene expression.