Abstract
Arabidopsis ABI3 gene is known as a transcriptional factor which expresses from very early stage of embryogenesis. In our previous work, we had already identified an embryo-specific promoter cis-element, Carrot Embryonic Element 1 (CEE1), in the C-ABI3 (carrot-ABI3) promoter. In this study, we analyzed the Arabidopsis ABI3 promoter region and identified the region inducing the ABI3 gene expression in embryo. At first, promoter activity of 4 ABI3-promoter-deletion:GUS constructs in zygotic and somatic embryos were analyzed. Next, binding activity with CEE1-binding-factors in carrot was checked on some CEE1-like sequences which exist in ABI3 promoter. From the results of both experiments, it was indicated that 100 bp region (Atd3-1L1) including two reverse-CEE1-like sequences is related to the ABI3 gene expression in embryo. Then, the Atd3-1L1 fragment was fused to CaMV35S minimum promoter and the gain-of-function experiments were conduced. The Atd3-1L1 region could induce gene expression in zygotic embryos from its early stage.
