Analyses of the Genomic Sequence and Promoter Activity of a Gene for a Protein Similar to Tat Binding Protein Isolated from Brassica rapa.

Abstract

We have previously isolated a cDNA clone, which is similar in sequence to the Tat binding protein (TBP) of human immunodeficiency virus 1, from the anthers of Brassica rapa and designated it BrTBP. In the present study we isolated a genomic clone of BrTBP from B. rapa and found several sequence motifs conserved in various pollen-expressed genes. The 1.7-kb promoter region of BrTBP was fused to the GUS gene and introduced into tobacco and Arabidopsis thaliana. GUS expression was observed exclusively in mature pollen after anthesis in transgenic tobacco, while it was observed in tricellular pollen starting two days before anthesis in A. thaliana. Such expression patterns at the late stage of pollen development have not been reported in other pollen-specific promoters. These results indicate that the BrTBP promoter region used in this study has a unique activation pattern in tobacco and A. thaliana.