Molecular cloning and characterization of two genes encoding sigma factors that direct transcription from a Bacillus thuringiensis crystal protein gene promoter.
Two sigma factors, sigma 35 and sigma 28, direct transcription from the Bt I and Bt II promoters of the cryIA(a) gene of Bacillus thuringiensis; this gene encodes a lepidopteran-specific crystal protoxin. These sigma factors were biochemically characterized in previous work (K. L. Brown and H. R. Whiteley, Proc. Natl. Acad. Sci. USA 85:4166-4170, 1988; K. L. Brown and H. R. Whiteley, J. Bacteriol. 172:6682-6688, 1990). In this paper, we describe the cloning of the genes encoding these two sigma factors, as well as their nucleotide and deduced amino acid sequences. The deduced amino acid sequences of the sigma 35 and sigma 28 genes show 88 and 85% identity, respectively, to the sporulation-specific sigma E and sigma K polypeptides of Bacillus subtilis. Transformation of the sigma 35 and sigma 28 genes into B. subtilis shows that the respective B. thuringiensis sigma factor genes can complement spoIIG55 (sigma E) and spoIIIC94 (sigma K) defects. Further, B. thuringiensis core polymerase reconstituted with either the sigma 35 or sigma 28 polypeptide directs transcription from B. subtilis promoters recognized by B. subtilis RNA polymerase containing sigma E and sigma K, respectively. Thus, sigma 35 and sigma 28 of B. thuringiensis appear to be functionally equivalent to sigma E and sigma K of B. subtilis. However, unlike the situation for sigma K in B. subtilis, the homologous sigma 28 gene in B. thuringiensis does not result from a late-sporulation-phase chromosomal rearrangement of two separate, partial genes.
Adams
L F
LF
Department of Microbiology, University of Washington, Seattle 98195.
Brown
K L
KL
Whiteley
H R
HR
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics; D001413:Bacillus thuringiensis / Q000235:genetics; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics*; D001427:Bacterial Toxins; D001483:Base Sequence; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D004731:Endotoxins; D005798:Genes, Bacterial; D006460:Hemolysin Proteins; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D012808:Sigma Factor / Q000235:genetics*; D014158:Transcription, Genetic
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D012808:Sigma Factor; C030956:insecticidal crystal protein, Bacillus Thuringiensis