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Optimized Ex-ovo Culturing of Chick Embryos to Advanced Stages of Development
Published on: January 24, 2015
Effects of polyamine limitation on nucleolar development and morphology in early chick embryos
Insights
Polyamines are crucial for early embryonic development. Inhibiting polyamine synthesis in chick embryos blocks development by affecting nucleolar formation and cell differentiation, highlighting polyamines
Area of Science:
- Developmental Biology
- Cell Biology
- Biochemistry
Background:
- Polyamines are essential for cell growth and differentiation.
- Early embryonic development is sensitive to disruptions in cellular processes.
Purpose of the Study:
- To investigate the role of polyamine synthesis in early chick embryo development.
- To determine the effects of polyamine inhibition on post-gastrular morphogenesis and nucleolar formation.
Main Methods:
- In ovo administration of DL-alpha-difluoromethylornithine (DFMO) to inhibit polyamine synthesis in chick embryos.
- Microscopic examination of embryonic development and ultrastructural analysis of nucleolar morphology.
Main Results:
- DFMO treatment permanently blocked post-gastrular development, characterized by a thickened primitive streak and condensed germ layers.
- Suppression of nucleolar formation and reduction in multiple nucleoli were observed in DFMO-treated embryos.
- Ultrastructural analysis revealed segregation of nucleolar material, indicating impaired function.
Conclusions:
- Polyamine synthesis is an obligatory step for epiblast cell differentiation into mesoderm.
- Polyamines are critical for normal nucleolar biogenesis and embryonic morphogenesis.
Abstract:
Inhibition of polyamine synthesis in early chick embryos by in ovo treatment with DL-alpha-difluoromethylornithine (DFMO), injected beneath the blastoderm after 5 h of incubation, permanently blocks post-gastrular development. After the first day of polyamine limitation, the embryos possess a thickened primitive streak. Further morphogenesis is blocked and the ectoderm and mesoderm are condensed around the streak. There is obvious suppression of nucleolar formation in 24 h DFMO-treated embryos. In the mesoderm obliquely in front of Hensen's node the frequency of nucleolus-possessing cells is only a few percent lower in DFMO-treated than in control embryos. However, in the same area the frequency of mesoderm cells possessing multiple nucleoli is about 50% lower in the polyamine-depleted embryos. At the ultrastructural level, mesoderm cells from 24 h DFMO-treated embryos show a reduction of the fibrillar component of the nucleolus with a resulting segregation of the nucleolar material. Our data indicate that stimulation of polyamine synthesis is an obligatory step in the differentiation of epiblast cells into mesoderm cells.
