CHARACTERIZATION OF NUCLEAR FACTORS FOR ELICITOR-MEDIATED ACTIVATION OF THE PROMOTER OF THE PEA PHENYLALANINE AMMONIA-LYASE GENE

The nuclear factors presumably associated with the activation of the g ene encoding phenylalanine ammonia-lyase by a fungal elicitor were cha racterized in pea (Pisum sativum L.) epicotyls. The TATA-proximal regi on was dissected and putative cis-regulatory elements in the promoter of pea phenylalanine ammonia-lyase gene 1 were examined by gel-mobilit y shift and in vitro footprinting analyses. Specific binding of the nu clear factors to the promoter-proximal regions of pea phenylalanine am monia-lyase gene 1 associated with elicitor-mediated activation was de tected at a region containing consensus sequence motifs of boxes 2 and 4 and other AT-rich sequences. The analyses of DNA fragments containi ng the deleted promoter regions suggested that a residue from -183 to -173 (ATTAGTAAGTGAT) was essential for a maximal activity of forming l ow-mobility complex (LMC) in the gel-mobility shift assay, and synthet ic oligonucleotides confirmed the presence of at least one nuclear com ponent associated with the formation of an active LMC. Competition exp eriments and treatment with Hoechst 33258 provided direct evidence tha t the formation of LMC with the promoter fragments from genes encoding phenylalanine ammonia-lyase and chalcone synthase in pea contained on e or more of the same proteins that recognize AT-rich sequence motifs for binding. It also suggests that common high-mobility group-like pro teins might be involved in the regulation of elicitor-inducible genes in pea.