PROMOTER ELEMENTS REQUIRED FOR SUGAR-REPRESSION OF THE RAMY3D GENE FOR ALPHA-AMYLASE IN RICE

There is increasing evidence shelving that cereal alpha-amylase gene e xpression is controlled not only by the classical hormonal regulation, but also by feed-back sugar repression. We demonstrated by in situ hy bridization that the sugar repression of rice alpha-amylase gene RAmy3 D takes place in scutellar epithelium cells of callus-forming rice emb ryos. We also used a transient expression system to study the cia-acti ng elements involved in the sugar repression of the RAmy3D promoter ac tivity. Site-directed mutagenesis of the 50-bp nucleotide sequence fro m -172 to -123 revealed that consensus sequences of G motif (TACGTA) a nd TATCCA TIC motif(GATA motif as its antisense sequence) are responsi ble for sugar repression. The promoter sequences required for sugar re pression are reported and discussed. (C) 1998 federation of European B iochemical Societies.