Preliminary Study on the Expression of BGT Gene in Transgenic Birch

In this paper, Southern blot analysis of the transgenic birch (Betula platyphylla Suk.) plants indicated that the the copy number of bgt varies from one to four. Of which 18.2 percent were single copy. Transcriptional expression of bgt gene in transgenic birch plants was analyzed by Northern blot. TGS has been found in four transgenic lines with one, three and four copies of bgt. Bgt gene was inserted into the prokaryotic vector pET 28a and transferred into E.coli BL21 (DE3) for expression of BGT fusion protein. After overnight cleavage with Thrombin and purification by immobilized metal ion affinity chromatography, the final BGT proteins were obtained with purity of 90%. The ELISA result showed that the BGT protein expression level in the transgenic birch plants ranged from 0.000% to 0.283% of total soluble protein. No significant correlation was found between copy number and expression level of bgt gene.