Cloning and sequencing of the gene for a putatively nematode-toxic crystal protein, Cry21Ba1, from Bacillus thuringiensis serovar roskildiensis.

摘要

We have cloned and sequenced a gene encoding a novel crystal (Cry) protein, Cry21Ba1, from Bacillus thuringiensis serovar roskildiensis. The gene, cry21Ba1, was amplified by polymerase chain reaction using template (alkaline-cell lysate or plasmid DNA fraction of the Bacillus) and primers (pairs of oligomeric DNAs designed from the conserved amino-acid sequence blocks of Cry5-Cry12-Cry13-Cry14-Cry21-type Cry proteins), and was cloned followed by sequencing. The gene, cry21Ba1, should be functional, because it has putative promoter sequences upstream of the initiation codon and an inverted repeat downstream of the stop codon. The open reading frame (ORF) of cry21Ba1 is a 3,858-bp DNA encoding Cry21Ba1 consisting of 1,286 amino acids. The nucleotide sequence of the cry21Ba1 ORF is 75% identical with that of the cry21Aa1 (the gene for a known nematode-toxic Cry protein, Cry21Aa1) ORF. The amino acid sequence of Cry21Ba1 is 67% identical with that of Cry21Aa1. High amino-acid-sequence similarity between these Cry proteins indicates that Cry21Ba1 is putatively nematode-toxic.