1987 Fiscal Year Final Research Report Summary
Formation of nucleus-like structure and gene expression in Xenopus fertilized eggs injected with exogenous DNAs.
| Project/Area Number |
61540523
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
動物発生・生理学
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| Research Institution | Kyushu University |
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Principal Investigator |
SHIOKAWA Koichiro Department of Biology, Faculty of Science, Kyushu University, 理学部, 助教授 (20037295)
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| Co-Investigator(Kenkyū-buntansha) |
YAMANA Kiyotaka Department of Biology, Faculty of Science, Kyushu University, 理学部, 教授 (20037162)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Xenopus fertilized eggs / Exogenous DNA injection / CAT gene expression / Concatenate formation / Circular plasmids / Enhancer-promoter / エンハンサー・プロモーター |
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| Research Abstract |
By injecting various kinds of DNAs into Xenopus laevis eggs, we clarified several fundamental characteristics of the behavior of exogenous DNAs in the developing embryonic cells of Xenopus laevis.
In the first year of the study, the effort was mainly focused on the formation of nucleus-like structures in the fertilized egg cytoplasm. We also characterized the ultrastructural features of the nucleus-like structures, and furthermore, showed that the nucleus-like structures formed are partitioned into the descendant cells as the injected embryos develop.
In the second year of the study, we mainly concerned the injections of bacterial chloramphenicol acetyltransferase (CAT) genes contained in the plasmids of circular and linearized conformations. It was found that both circular and linear DNAs were expressed extensively in the developing embryos. The expression was dependent on the presence of enhancer element in the injection of circular plasmids, whereas it was not dependent in the case of the injection of linearized DNAs. Southern blot analysis of the DNAs recovered from the linearized DNA-injected embryos revealed that the injected DNAs formed large concatenates. Therefore, we proposed that the active expression may be due to the concatenation of the linear DNAs and probably due to the association of the large concatenates with cellular structures, such as nuclear matrix, so that they can generate torsional stress which appears to be needed for the active gene expression from the exogenous DNAs.
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