Abstract：To insight into the characteristic of its endosperm-specific promoting regulation activity, –2510- -1bp sequence of the wheat pbf (prolamin-box binding factor) promoter was cloned by Polymerase Chain Reaction (PCR) amplification and a series of pbf deletion fragments were fused with the β-glucuronidase (GUS) reporter gene (UidA) and 3΄ non-coding region of the nopaline synthase gene (nos) in pCAMBIA1381z vector. And these fusions of pbf deletion had been transformed into wheat endosperm in vitro and GUS transient expressions regulated by pbf promoter deletions had been assayed subsequently. Results of GUS transient assay in wheat endosperm and Loss of function displayed that –2510- -1bp pbf sequence could show promoting activity in endosperm, however, 5’ and 3’ deletions of –2510- -670bp, –1288- -1bp sequence resulted in undetectable promoter activity; inner deletion of –2160- -689bp evidently decreased the GUS expression activity. Compared with levels of GUS expression of the Cauliflower Mosaic Virus (CaMV) 35S promoter used as a control, the full sequence of pbf promoter had lower activity. In this article, the number and sorts of main motifs in pbf promoter sequence had been described. It was suggested that the presence of a Skn-1-like motif (G/ATCAT) and a –300bp element (TGHAAARK) in the promoter sequence might be important and essential for expressing pbf promoter activity and specificity. Effects of wheat endosperm developing state and GUS-transient assay system on promoter activity assay had been discussed also.
