Comparison of Stable Expressions of Foreign Genes Driven by Different Promoters in Transgenic Dunaliella salina / 中国生物工程杂志

ABSTRACT

The purpose was to compare the difference between transgene expressions driven by homologous duplicated carbonic anhydrase (DCA) promoter and foreign CaMV35S promoter in the unicellular green alga, Dunaliella salina(D.salina).The CaMV35S promoter-bar construct and DCA promoter-bar construct into D.salina by a Backon 2000 electroporation system were introduced. After the repeated selections with the phosphinothricin (PPT) of 3mg/L, 3 PPT-resistant phenotype transformants were isolated from the CaMV-bar and DCA-bar pools of transformants of D. salina, respectively. The results of PCR and sequencing showed that bar genes were stably integrated into the genome of D.salina, and Southern bolts showed the number of transgene copy had no significant difference between both promoters. Semi-quantitive RT-PCR indicated that the mRNA levels of bar gene were higher in DCA-bar transformants than the CaMV-bar transformants, and could be increased under the induction of high salt in DCA-bar transformants but not in the CaMV-bar transformants. Analysis of growth rate of transformants showed DCA-bar transformants achieved the log stage faster than the CaMV-bar transformants. It is concluded that the homologous promoters have more advantages than the foreign promoters in the transgenic D.salina.