Cloning and study of the expression of a novel cry1 la-type gene from Bacillus thuringiensis subsp. kurstaki

摘要

Aims: Cloning and expression of a new ciy1 Ia-type gene of Bacillus thuringiensis. Methods and Results: PCR amplification, using gene cry1 I-specific primers revealed the presence of such a gene in the strain BNS3 of Bacillus thuringiensis subsp. kurstaki. The cloning and sequencing from BNS3 of the cry1 Ia-type gene, called crybns3-3, showed an open reading frame of 2160-bp, encoding a protein of 719 amino acid residues. Both nucleotide and amino acid sequences similarity analysis revealed that the crybns3-3 is a new cry1 Ia-type gene, presenting several differences from the cry1 Ia-type genes. The study of the expression of crybns3-3 by Northern blot and RT-PCR showed that it was transcribed. The expression of crybns3-3 under the control of BtI and BtII promoters revealed that Crybns3-3 would co-crystallize with the endogenous delta-endotoxins. Conclusions: crybns3-3 is a novel oylla gene isolated from B. thuringiensis subsp. kurstaki strain BNS3. Significance and Impact of the Study: The characteristics of crybns3-3 indicate that it is a new cry1 Ia-type gene. Amino acid residue substitutions presented in Crybns3-3 could be exploited for both toxicity and specificity studies. Crybns3-3 would interact and co-crystallize at least partially with the endogenous delta-endotoxins of BNS3, and then participate in the formation of the parasporal crystal inclusions.