| Project/Area Number |
16570170
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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 | Niigata University |
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Principal Investigator |
MAENO Mitsugu Niigata University, Institute of Science and Technology, Associate Professor, 自然科学系, 助教授 (10190315)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2004: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Xenopus laevis / Transcription factor / Tail organizer / BMP / Neural Differentiation / FGF / Neptune / Morphogenesis / 神経冠 / 境界形成 / KLF / 尾部 / オーガナイザー |
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| Research Abstract |
In order to elucidate the molecular mechanisms underlying the posterior axis and tail formation in embryogenesis, the function of Neptune, a zinc-finger transcription factor, in Xenopus laevis embryos was investigated. Injection of neptune mRNA into the animal pole area of embryos resulted in the formation of an additional tail structure that included a neural tube and muscle tissue. This activity required FGF signaling since coinjection of a dominant-negative FGF receptor RNA (XFD) completely blocked the formation of a tail structure. A loss-of-function experiment using a fusion construct of neptune and Drosophila engrailed (en-neptune) RNA showed that endogenous Neptune is necessary for formation of the posterior trunk and tail. Furthermore, activity of Neptune was necessary for the endogenous expression of brachyury and fgf-8 at the late gastrula stage. These findings demonstrate a novel function of Neptune in the process of anterior-posterior axis formation through the FGF and brachyury signaling cascades. An experiment using a combination explant with ventral and dorsal marginal tissues showed that cooperation of these two distinct tissues is important for the tail formation and that expression of Neptune in prospective ventral cells may be involved in the activation of the process of tail formation. We further investigated the function of Neptune in neural tissue formation since neptune transcript is expressed in the border region between neural tissue and epidermis at the neurula stage. Introduction of hormonally regulated version of Neptune and Morpholino oligo in the ectoderm cells demonstrated a function of Neptune in restricting the neural area from the epidermis forming area. Overall results suggest that Neptune is a key regulator with multi-functions in vertebrate embryogenesis.
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