Factors involved in nuclear reprogramming during early development in the rabbit

Area of Science:

• Reproductive Biology
• Developmental Biology
• Cellular Reprogramming

Background:

• Nuclear reprogramming is crucial for development, but malfunctions can be deleterious.
• Understanding these processes in early embryonic stages is vital for reproductive technologies.

Purpose of the Study:

• To evaluate nuclear reprogramming mechanisms in rabbit zygotes, parthenotes, and nuclear transfer embryos.
• To identify potential developmental defects related to DNA replication, nucleolar activity, and protein phosphorylation.

Main Methods:

• Analysis of DNA replication patterns.
• Assessment of nucleolar transcriptional activity using fibrillarin labeling.
• Localization of phosphorylated epitopes with the MPM-2 antibody.

Main Results:

• Nuclear transfer embryos showed signs of DNA re-replication.
• Parthenogenetic embryos exhibited delayed DNA replication, potentially due to activation stimulus deficiencies.
• Nucleolar activity (fibrillarin label) was impaired in some blastomeres of nuclear transfer and parthenogenetic embryos.
• MPM-2 labeling patterns varied, with nuclear transfer embryos showing normal patterns and parthenogenetic embryos' patterns depending on calcium stimulation.

Conclusions:

• Defects in DNA synthesis, nucleolar activity, and phosphorylation occur during rabbit early embryonic development.
• These defects are likely linked to improper activation stimuli and chromosome condensation issues in transplanted nuclei.
• The findings highlight critical checkpoints in nuclear reprogramming that require optimization.