2002 Fiscal Year Final Research Report Summary
Initiation mechanism of the zygotic gene expression in Xenopus mid-blastula embryo
| Project/Area Number |
13680811
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Developmental biology
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| Research Institution | Kwansei Gakuin University |
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Principal Investigator |
KINOSHITA Tsutomu Kwansei Gakuin Univ., Sci. & Tech., Prof., 理工学部, 教授 (30161532)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Xenopus laevis / Mid-blastula transition / Gene expression / Xbrachyury / Notch signaling / Maternal factor |
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| Research Abstract |
Since Newport and Kirschners' model (1987), it has been remained unknown what maternal factor controls the Mid-blastula transition. Here, in order to examine the initiation mechanism of the zygotic gene expression, we have tried to isolate a novel transcriptional regulator that has been expressed maternally and participates in the regulation of the zygotic gene expression prior to gastrulation. By screening the cDNAs that show maternal gene expression, we have isolated several novel genes. Xoom encoded the transmembrane protein that has a close relation to the polymerization of actin filament, and played a role in morphogenetic movement of gastrula embryo. A novel POZ/Zinc-finger transcription factor encoded by Champignon participated in the morphogenetic regulation through the production of the extracellular matrix. XEXTI, showing active gene expression during the oogenesis, also played a role in the production of the extracellular matrix. In contrast to these molecules showing no direct relation to the zygotic gene expression, Notch-related molecules had close relation to the gene expression in the early stage of gastrula embryo. In this study, we have cloned X-Serrate-1, which encodes one of the Notch ligand. X-Serrate-1, X-Notch-1, Xsu(H) showed ubiquitous gene expression from oogenesis to tadpole stage of development. Gene expression of the target gene, ESR1, demonstrated that these Notch-related molecules are functional in the early gastrula embryo, but the signaling passway is blocked before MBT probably by inhibiting the enzyme activity of Presenilin. Loss of function experiment showed that Xsu(H)-mediated transcriptional regulation is essential to the zygotic gene expression.
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