Assessment of common regulatory regions required for the endosperm-specific expression of rice storage protein glutelin genes by hybrid promoters.

摘要

Most of the rice (Oryza sativa) storage protein glutelin genes are coordinately expressed during seed maturation, although there is considerable divergence in the 5' flanking regions between members of GluA and GluB subfamilies. Hybrid promoters among the 5' distal and proximal sequences of GluA-3 and GluB-1 genes were constructed to elucidate the regulatory mechanism(s) responsible for their common endosperm-specific expression. The constructs were transcriptionally fused to the firefly luciferaseor beta-glucuronidase reporter gene and their activities were examined in maturing tobacco seeds and leaves. A set of conserved motifs, the AACA motif and GCN4 or G-box-like motif, in the proximal regions of both the glutelin genes was shown to be cis-elements required for endosperm-specific expression. In addition, it has been demonstrated that GluA-3 and GluB-1 genes differ in the interactions between the cis-elements in the distal and the proximal promoter regions, and this could lead to observed differences in the quantitative regulation between the glutelin genes.