PCR Synthesizing、 Cloning and Sequencing of 5’ End of BT Toxin Gene

By Polymerase Chain Reaction(PCR), the 5’ end of Bacillus thuringieusis var. kurstaki HD-1 toxin gene has been synthesized, using the total DNA of the bacterium as template. The recombinant plasmid pQC20 has been obtained, cloning the PCR fragment into the Bluescript plasmid vector in E. coli. According to the restriction map, the insert of pQC20 belongs to the 5.3 Kb type gene in the Kronstad’s classification system for restriction fragment of length polytype of toxin protein gene. The sequencing result showed that, the synthesized 1959 bp nucleotides are almost the same as the published sequence of 5.3 Kb type toxin gene with only one-nucleotide difference. This 5’ end fragment contains the complete sequence for encoding the activated toxin.