K-084. MnoR Is a Positive Transcriptional Regulator of mno Gene in Mycobacterium sp. strain JC1 DSM 3803

H. Park1, Y. Ro2, S. Kim1, J. Lee1, Y. Kim1;
1Yonsei Univ., Seoul, REPUBLIC OF KOREA, 2Konkuk Coll. of Med., Chungju, REPUBLIC OF KOREA.

Mycobacterium sp. strain JC1 DSM 3803 is a bacterium able to grow on methanol as a sole source of carbon and energy. We previously reported that methanol:N,N-dimethyl-4-nitrosoaniline oxidoreductase (MNO) was found to play a key role in the oxidation of methanol and mnoR might be a transcription regulator involved in the expression of mno in the bacterium. MnoR is known as a transcription regulator of TetR family containing a helix-turn-helix DNA binding motif. To identify the function of mnoR in Mycobacterium sp. strain JC1, deletion mutants in the mnoR gene were constructed by homologous recombination. Mutants defective in the production of MnoR did not grow on methanol, but the ability to grow on methanol was restored by complementation with mnoR. One binding complex was formed when purified MnoR was incubated with DNA fragments covering the putative mno promoter region. Footprinting experiments identified that MnoR binds to the putative promoter region containing an inverted repeat region (5'-GCAGCGTGCTGC-3'). These results indicate that MnoR is involved in the oxidation of methanol in Mycobacterium sp. strain JC1 by acting as an activator of the mno gene expression.