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Updated: Jul 18, 2026
14:17
Nuclear Transfer into Mouse Oocytes
Published on: November 30, 2006
Nucleolar remodeling in nuclear transfer embryos
Jozef Laurincik1, Poul Maddox-Hyttel
1Constantine the Philosopher University, Faculty of Natural Sciences, Trieda A. Hlinku, SK-949 74 Nitra, Slovak Republic. jlaurincik@ukf.sk
Advances in Experimental Medicine and Biology
|December 21, 2006
Summary
Ribosome biogenesis via ribosomal RNA (rRNA) gene transcription in the nucleolus marks embryonic genome activation. Nuclear transfer protocols impact nucleoli development and protein localization, affecting embryo potential.
Area of Science:
- Reproductive Biology
- Developmental Biology
- Cellular Biology
Background:
- Ribosome biogenesis, driven by ribosomal RNA (rRNA) gene transcription in the nucleolus, is crucial for cell function.
- Nucleolus formation serves as a key indicator of embryonic genome activation and developmental potential in mammalian embryos.
- Evaluating nucleolar development is vital for assessing the success of various nuclear transfer (NT) techniques.
Purpose of the Study:
- To investigate the timing of nucleolus formation and rRNA gene transcription in bovine embryos.
- To assess the impact of different nuclear transfer methods (in vivo, embryonic cell NT, somatic cell NT) on nucleolar development.
- To analyze the localization of key nucleolar proteins in relation to developmental potential.
Main Methods:
- Comparative analysis of nucleolus formation timing across different bovine embryo developmental pathways.
- Microscopic examination of nucleolar structure and protein localization in various NT embryo types.
- Assessment of rRNA gene transcription and ribosome biogenesis markers.
Main Results:
- In vivo derived bovine embryos show distinct nucleoli by the 4th cell cycle.
- Embryonic cell NT embryos exhibit nucleoli by the 5th cycle, while somatic cell NT embryos show them by the 3rd cycle.
- Intergeneric NT embryos (bovine somatic cell to ovine cytoplast) fail to develop functional nucleoli. Aberrant protein localization is observed in NT embryos, indicating reprogramming issues.
Conclusions:
- Nucleolus formation timing varies significantly based on the NT method used.
- Aberrant nucleolar protein localization in NT embryos suggests underlying genomic reprogramming defects.
- These findings highlight potential causes for abnormalities in offspring derived from NT embryos and inform strategies for improving NT efficiency.
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