Sequences of Three Arabidopsis General Regulatory Factor Genes Encoding GF14 (14-3-3) Proteins

Plants must be able to adapt quickly to unfavorable changes in their environment to ensure survival. This adaptation is initiated by events at the molecular level that produce a rapid increase in the expression pattern of genes necessary to protect the plant from life-threatening environmental stresses. One such gene is Arubidopsis alcohol dehydrogenase, which increases expression with the onset of hypoxic conditions (Dolferus and Jacobs, 1991). The alcohol dehydrogenase gene contains a cis-acting promoter element, the G-box (5’-CCACGTGG-3’) (Ferl and Laughner, 1989). When the G-box is mutated, alcohol dehydrogenase expression is reduced and in vitro protein binding is disrupted (McKendree and Ferl, 1992). The G-box also appears in the promoters of other stress-induced plant genes (Williams et al., 1992), including the light-regulated small subunit of Rubisco, Chl u/b-binding protein and chalcone synthase genes and the hormone-regulated early Metlabeled protein and the rub-16 family of genes. A nuclear protein complex binds to the Arabidopsis G-box (McKendree et al., 1990), and genes encoding G-box binding factors have been cloned from Arubidopsis (Schindler et al., 1992). A monoclonal antibody (anti-GF14) generated against the partially purified G-box-binding protein complex was used to identify and isolate five cDNA clones of proteins associated with the G-box-binding complex (Lu et al., 1992). These five proteins, which do not directly bind to the G-box element, were designated GF14x, GF14w, GF14+, GF144, and GF14v (Lu et al., 1994a). These plant proteins were named GF14 because they exhibited greater than 60% identity with a highly conserved class of proteins known as 14-3-3 proteins that were found in yeast, plants, and animals. Mammalian brains also contain 14-3-3 homologs that function to activate Tyr and Trp hydroxylases