title: A transposon-like structure related to the delta-endotoxin gene of Bacillus thuringiensis.
abstract: A DNA segment (Th-sequence) has been found in several strains of Bacillus thuringiensis. This Th-sequence [3 megadaltons (Md)] induces adjacent deletions when it is located in the pAM beta 1 plasmid derived from Streptococcus faecalis. Electron microscopic examination of reannealed single strands of one plasmid (pMT9) carrying such a deletion revealed that the Th-sequence corresponds to a single-stranded loop (2.8 Md) bounded by a short double-stranded stem (less than 0.2 Md). Southern blotting experiments established that in B. thuringiensis the Th-sequence was generally located on the large plasmid which also harbours the gene coding for the delta-endotoxin (crystal protein). Hybridization and heteroduplex analysis of the extrachromosomal DNA from the berliner 1715 strain demonstrated that the crystal gene and the Th-sequence are located in close vicinity on a 42-Md plasmid and that they are separated by a 1.3-Md DNA segment. This DNA segment is repeated in inverted orientation, once immediately adjacent to the Th-sequence and once 1.8 Md beyond the crystal gene. A model for the organization of these DNA sequences inside a transposon-like structure is proposed.
mesh_terms: D001413:Bacillus thuringiensis / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004277:DNA, Single-Stranded / Q000302:isolation & purification; D004731:Endotoxins / Q000235:genetics*; D005796:Genes; D005798:Genes, Bacterial; D006460:Hemolysin Proteins; D007306:Insecticides; D008854:Microscopy, Electron; D009693:Nucleic Acid Hybridization; D010944:Plants; D010957:Plasmids
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004277:DNA, Single-Stranded; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D004262:DNA Restriction Enzymes