TRANSCRIPTION FACTORS IN PLANTS - PHYSIOLOGICAL FUNCTIONS AND REGULATION OF EXPRESSION

The control of gene expression in plants, as in all other living organ isms, is essential for regulation of biological processes, such as bod y planning, development, differentiation and responses to various envi ronmental signals. Transcription is the initial step at which genes ar e selected for expression and for modulation of levels of expression. In efforts to elucidate the mechanisms that control gene expression in plants, numerous DNA-binding proteins that interact with plant promot ers have been identified and the corresponding cDNAs have been cloned. Some of these proteins are structurally similar to well-characterized transcription factors in animal or yeast cells, while others seem to be unique to plants. Recent studies of plant transcription factors hav e suggested the biological and molecular functions of several factors. It also appears that post-transcriptional control of levels of transc ription factors, as well as the strictly controlled expression of thei r genes, both temporary and spatially, may be important in the regulat ion of expression of target genes. This review summarizes recent findi ngs related to the physiological functions of plant transcription fact ors and the regulation of their activities.