Isolation and characterization of the wheat prolyl isomerase FK506-bindingprotein (FKBP) 73 promoter

The wheat FK506-binding protein (FKBP) 73 is a member of the peptidyl proly l cis-trans isomerase gene family, which catalyses the interconversion betw een the cis and trans forms of the peptide bond preceding proline residues in proteins. A 3.5 kb sequence 5' upstream of the ATG codon of the wheat FK BP73 was isolated from a wheat genomic library, and characterized by deleti on analysis and transient expression in wheat embryos. The 1517 bp fragment is referred to as the full promoter due to the maximal activity of the fus ed luciferase reporter gene. Sequence analysis revealed the presence of thr ee abscisic acid (ABA)-responsive elements (ABREs) proximal to coupling ele ments (CE1-like), a putative lectin box, two putative binding sites for the myb transcription factor and a 36 bp fragment which exhibits 100% identity to the pSau3A9 clone located in the centromeric region of wheat chromosome s. In a transient expression assay the promoter preserved the tissue specif icity described in vivo, namely it is expressed only in germinating embryos and young shoots. The promoter was induced 1.9-fold by ABA, the minimal pr omoter was designated at -221 and the TATA box located at -137. The inducib ility by ABA and the expression during germination may indicate that FKBP73 belongs to the group of genes induced by ABA upon germination.