1995 Fiscal Year Final Research Report Summary
Analysis and improvement of the protein secretion pathway of Bacillus subtillis on the functional similarity between mammalian SRP 7S RNA and B.subtilis scRNA
| Project/Area Number |
05454130
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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 |
Applied molecular and cellular biology
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| Research Institution | UNIVERSITY OF TSUKUBA |
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Principal Investigator |
YAMANE Kunio University of Tsukuba, Institute of Biological Sciences, Professor, 生物科学系, 教授 (20013336)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Kouji University of Tsukuba, Institute of Biological Sciences, Assistant professor, 生物科学系, 講師 (40212097)
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| Project Period (FY) |
1993 – 1995
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| Keywords | Bacillus subtilis / protein secretion pathway / signal recognition particle / mammalia SRP 7S RNA / B.subtilis scRNA / Ffh, an SRP54 homologue / gene engineering |
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| Research Abstract |
Bacilus subtilis and relating strains have a strong ability to produce extracellular enzymes such as alpha-amylases for starch degradation to produce glucose and proteases for detergent. To apply this hyper production ability of extracellular enzymes in B.subtilis to the production of human serum albumin, interferons and others by B.subtilis, many experiments have been examined by many laboratories including us using gene engineering technology. B.subtilis transformants, by which human gene products could be produced, have been isolated. However, the produced amounts of them were small and the gene products could not be accumulated in the culture medium as the extracellular enzymes. To improve this situation, many protease-defecient mutants have been developed. But they were not sufficient to use as the host to produce those materials.
To dissolve these problems, we analyzed the protein secretion pathway of B.subtilis on the signal recognition particle, which has been found as the protein secretion apparatus of mammalian cells. B.Subtilis contains stable small cytoplasmic RNA (scRNA) abundantly consisting of 271 nucleotides. Its secondary structure seems to be rather similar to mammalian SRP 7S RNA (300 nucleotides) than E.coli 4.5S RNA (114 nucleotides). We found that scRNA forms a complex with three kind of proteins, whose molecular size was estimated to be 8.2s. We then constructed conditional mutants of scRNA and proteins, we found that the complex directly relates to the protein translocation and cell growth. Based on these findings, we would like to improve the protein secretion of B.subtilis.
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