Present address: Ceres Inc., 3007 Malibu Canyon Road, Malibu, CA 90265, USA.
Quantitative nature of the Prolamin-box, ACGT and AACA motifs in a rice glutelin gene promoter: minimal cis-element requirements for endosperm-specific gene expression
Article first published online: 25 DEC 2001
The Plant Journal
Volume 23, Issue 3, pages 415–421, August 2000
How to Cite
Wu, C.-Y., Washida, H., Onodera, Y., Harada, K. and Takaiwa, F. (2000), Quantitative nature of the Prolamin-box, ACGT and AACA motifs in a rice glutelin gene promoter: minimal cis-element requirements for endosperm-specific gene expression . The Plant Journal, 23: 415–421. doi: 10.1046/j.1365-313x.2000.00797.x
- Issue published online: 25 DEC 2001
- Article first published online: 25 DEC 2001
- Received 10 November 1999; revised 10 April 2000; accepted 8 May 2000.
- storage protein;
- gene regulation;
The −197 bp promoter of the rice seed storage protein gene, GluB-1, is capable of conferring endosperm-specific gene expression. This proximal 5′ flanking region contains four motifs, GCN4, AACA, ACGT and Prolamin-box, which are conserved in many seed storage protein genes. We previously showed that multiple copies of GCN4 conferred endosperm expression pattern when fused to the −46 core promoter of CaMV 35S. In this paper we demonstrate, using a similar approach, that tandem repeated copies of any of the other three motifs are unable to direct expression in seeds as well as other tissues of transgenic rice plants. Mutational analysis of individual motifs in the −197 bp promoter resulted in remarkable reductions in promoter activity. These results indicate that the GCN4 motif acts as an essential element determining endosperm-specific expression and that the AACA, ACGT and Prolamin-box are involved in quantitative regulation of the GluB-1 gene. A set of gain-of-function experiments using transgenic rice showed that either the Prolamin-box or AACA, although often coupled with GCN4 in many genes, is insufficient to form a functional promoter unit with GCN4, whereas a combination of GCN4, AACA and ACGT motifs was found sufficient to confer a detectable level of endosperm expression. Taken together, our results provide direct insight into the importance of combinatorial interplay between cis-elements in regulating the expression of seed storage protein genes.