1989 Fiscal Year Final Research Report Summary
Molecular genetic study on expression of self-resistant genes in antibiotic producer microorganism
| Project/Area Number |
63480028
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
発酵工学
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
NIIMI Osamu Hiroshima University, Faculty of Engineering, Professor, 工学部, 教授 (60034360)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIYAMA Masanori Hiroshima University, Faculty of Engineering, Assistant professor, 工学部, 助手 (30106801)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Streptomycin / Secondary Metabolic Regulation / Resistant genes / Genes Expression / RNA polymerase |
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| Research Abstract |
Two streptomycin self-resistant genes (strA and smk) were used for studies on a regulatory mechanism of secondary metabolism. Expression of the two genes and contribution of two genes toward self-resistance in antibiotic producer organism were studied and revealed several results as follow
1. Two genes were inserted to pIJ 702, streptomyces plasmid vector, respectively and were transformed into SM producing streptomyces griseus. No increase of SM resistance and SM productivity were detected in strains carrying the plasmid vector.
2. A promoter probe plasmid vector for Streptomyces were constructed with the genes producing melanin pigment. A promoter sequence of smk genes was decided using the promoter probe vector.
3. Transcription of the two genes were checked in mycelium of different culture ages during SM fermentation. Form results of Northern hybridization, it was revealed that the strA genes was transcribable in mycelium of only SM producing phase and the smk genes was resting genes in all mycelium tested.
4. SM sensitive mutants were isolated from Streptomyces griseus. These mutants possessed the normal (not mutate) strA genes. But mRNA transcribed from strA was not detected in the mutants by Northern hybridization method.
5. Purified RNA polymerase were prepared respectively from SM resistant and sensitive strains. The strA genes was transcribed to its mRNA with in vitro transcriptional system prepared from SM resistant strain, but it was not transcribed with the system from SM sensitive one.
From the above results. it was revealed that RNA polymerase specific to secondary metabolism needs for expression of genes concerning to secondary metabolism.
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