1988 Fiscal Year Final Research Report Summary
Structure and Function of the plasmid genes associated with epethelial invasion in Shigella Flexneri
| Project/Area Number |
61440035
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
細菌学
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| Research Institution | University of Tokyo |
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Principal Investigator |
YOSHIKAWA Masanosuke Institute of Medical Science, Univ. of Tokyo, 医科学研究所, 教授 (80012714)
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| Co-Investigator(Kenkyū-buntansha) |
MAKINO Sou-ichi Institute of Medical Science, Univ. of Tokyo, 医科学研究所, 助手 (30181621)
SASAKAWA Chihiro Institute of Medical Science, Univ. of Tokyo, 医科学研究所, 助教授 (70114494)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Pathogenicity / Virulence / tolic Shigella / Cell invasion / Plasmid / Recombinant DNA technology / Molecular genetics / 転写アクチベータ |
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| Research Abstract |
Bacillary dysentery is an invasive infectious diseases of the human colon. A 230-kb plasmid as well as genetic loci on the chromosome have been implicated in its pathogenesis. Results obtained by the molecular genetic analysis mainly of the plasmid genes, virG, virF, and virB and on a chromosome gene kcpA are summarized as follows. 1. The SalI restriction map of the plasmid, pMYSH6000 of S. flexneri 2a was made. Tn5 insertions into pMYSH6000 were isolated, and the sites of Tn5 assigned to each of the 23 SalI fragments. Some insertions into SalI-G, SalI-F and 4 contiguous SalI fragments, B-P-H-D resulted in avirulence. The Tn5 insertions into B-P-H-D defined 5 separable regions, tentatively designated as Regions 1 through 5. A single cistron virG consisting of 3306 bp and encoding a 116 kd protein required for intercellular spread has been defined within SalI-G. A cistron virF on SalI-F fragment has been identified and sequenced. Expression of 4 immunodominat proteins, one encoded by virg, and 3 encoded by Region 2 were found to be positively regulated by the 30 kD virF protein at the transcriptional level. This occurred directly for the virG but, for 3 Region 2 genes, exclusively via transcriptional activation by a 33 kd protein activator encoded by another cistron virB on Region 1. 2. A chromosomal locus kcpA containing a single cistron has been cloned and the nucleotide sequence determined. A 12.3 kd product also required for intercellular spread has been identified. The complete understanding of the pathogenesis of bacillary dysentery at the molecular level still remains far in the distance. It is our hope that these approaches may facilitate us in reaching the final goal.
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