Embryo and anther regulation of the mabinlin II sweet protein gene in Capparis masaikai Lévl.

Mabinlin II is one of the major sweet proteins stored in the seeds of Capparis masaikai Lévl. Its promoter region (779 bp) located 5' upstream of the mabinlin II gene has been isolated and named as MBL-779 (GenBank accession number, EU014073). This promoter contains two typical TATA box regions and a series of motifs related to seed-specific promoters, such as ACGT motifs, RY motif, napin motif, and G box. The MBL-779 promoter drove GUS gene to transiently express in the embryos of bean, maize, and rice seeds or to constantly express in the embryos and anthers of the transgenic Arabidopsis. The MBL-779 promoter regulated gene expression from approximately the 12th day and peaked on approximately the 16th day after flowering in Arabidopsis. The -300-bp promoter region is a minimal sequence required to functionally regulate gene expression. The CAATs at -325 to -322 bp and -419 to -416 bp and the region at -485 to -770 bp play a role in the quantitative regulation of gene expression. The RY motif, CATGAC, at -117 to -112 bp and the ACGT within the G box (CACGTG) at -126 to -123 bp positively regulate gene expression.