Although Mycobacterium tuberculosis is one of the first identified pathogenic bacteria in man, the biochemical and immunochemical characterization of the bacterial antigens have been limited by difficulties in dealing with this bacilli in vitro. As the cloning and DNA recombination technique have been considered to be an effective strategy to survey the genes encoding protein antigens relevant for such studies, M. tuberculosis genomic DNA was isolated and the fragments with randomly generated endpoints were used to construct a lambda gtll recombinant library. The antigens encoded by the recombinant could be accumulated in Escherichia coli strain defective in protein degradation (lon), because gtll permits insertion of foreign DNA in the β-galactosidase structural gene, lac Z, and promotes synthesis of hybrid proteins. A very low molecular weight polypeptide, compared with the size of recombinant DNA, was detected by Western blotting with hyperimmune rabbit serum. These results have indicated that mycobacterial DNA could be expressed in E. coli, but the transcription-translation apparatus of this enterobacteria would recognize some M. tuberculosis amino acid-coding-DNA sequence as the initiation or termination codon.
ヒト型結核菌Mycobacterium tuberculosis 遺伝子のクローニングと組み換え遺伝子の大腸菌における発現
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