Cloning and function identification of the promoters and terminator of sugar beet chloroplast gene psbA

Using two pairs of specific primers, DNA fragments containing the promoter PpsbA of psbA gene and terminator TpsbA of psbA gene, were obtained by PCR from Beta vulgaris. L chloroplast genomic DNA. Sequence analyzing results showed that the functional domains such as −35 domain, −10 domain and the translation control sequence motif in the cloned promoters the highly conserved to Nicotiana tabacum. The promoter PpsbA and the terminator TpsbA were cloned and the prokaryotic expression vectors pSKPTA of aadA gene were constructed by using PpsbA and the terminator TpsbA. Prokaryotic expression results showed that the promoters PpsbA cloned were functional and their activities could be controlled by the RNA polymerase of E.coli BL21 and the aadA controlled by them could be constitutively expressed E.coli in BL21.