BZIP TYPE TRANSCRIPITON FACTORS REGULATING THE EXPRESSION OF RICE STORAGE PROTEIN

摘要

cDNAs (RISBZ1, RISBZ4 and RISBZ5) encoding bZIP type transcriptional factors are isolated from a rice seed-origin cDNA library. These cDNAs encode novel proteins and show binding activity to the GCN4 motif. RISBZ1 activates the transcription 100-fold or higher via the GCN4 motif. The expression of RISBZ1 precedes the expression of a seed storage protein gene and observed exclusively in seeds in the ripening stage, which suggests that RISBZ1 regulates the expression of the rice seed storage protein. To facilitate the binding to the RISBZ1 transcription factor, the recognition sequence (GGN4 motif) of the transcription factor is ligated in series and transferred into a promoter of a specific storage protein. Thus, the expression of a foreign gene under the regulation of the thus modified promoter can be elevated.