Abstract
Arabidopsis ASML1/WRI1, an AP2-type transcription factor expressed during seed development, is thought to be involved in the promotion of conversion of sucrose to oil, since it binds to promoters of genes involved in fatty acid synthesis in plastids and activates their expression. Introduction of mutations to two ASML1/WRI1 binding sites (AW-BOX) in the PL-PK promoter abolished expression of the GUS fusion gene not only in developing seeds but also in vegetative tissues. Among members of AP2-subfamily transcription factors which contain two AP2 DNA binding domains, WAT1 with the highest structural similarities to ASML1/WRI1 showed specific binding to the AW-BOX and trans-activated expression of reporter genes under the promoters of genes involved in fatty acid synthesis. Unlike ASML1/WRI1, expression of WAT1 is higher in vegetative tissues than in developing seeds. Effects of disruption and overexpression of WAT1 on the expression of genes involved in fatty acid synthesis are examined.
