A NOVEL DELTA-ENDOTOXIN GENE CRYIM FROM BACILLUS-THURINGIENSIS SSP. WUHANENSIS

A new cryI-related sequence designated cryIM was cloned using an immun oscreening technique from ssp. wuhanensis of Bacillus thuringiensis (B T), previously reported to produce multiple Cry proteins [Chestukhina et al, (1994) Can. J. Microbiol. 240, 1026-1034], Analysis of the cryI M nucleotide sequence revealed an ORF, BTII-type promoter-like sequenc e, peculiar for such genes, a translation initiation element and a put ative transcription terminator, Nevertheless, its product was not prev iously found in the crystals of the host strain [Chestukhina et al. (1 994) Can. J. Microbiol. 240, 1026-1034] which shows its weak or absent natural expression, The amino acid sequence of 1151 residues encoded by the continuous reading frame of cryIM is not identical but is essen tially similar to the other delta-endotoxins of the CryI class, An IS2 31-like sequence was found 400 bp downstream of the cryIM stop codon a nd a fragment of the cryIAb gene was located 3 kb upstream of its init iator codon in the same orientation, Artificial expression of the clon ed gene in E, coli under the control of the lacZ promoter allowed us t o obtain its hypothetical protein product. (C) 1997 Federation of Euro pean Biochemical Societies.