Cloning and overexpression of thermostable DNA polymerase gene in Escherichia coli.

Thermostable DNA polymerase genes had been amplified from Thermus aquaticus YT-1 using the PCR technique. The amplified 2.5-kb DNA fragment was inserted into pUC18 and confirmed to be a thermostable DNA polymerase gene by restriction mapping and DNA sequencing. The insert fragment was then combined into an expression vector, pBV221. This recombinant plasmid overexpressed a 94-kDa of recombinant protein in E. coli. A 100-mL E. coli. culture could yield 1.5 x 10(5) units of Taq DNA polymerase, which could be applied in the PCR.