Reprogramming following somatic cell nuclear transfer in primates is dependent upon nuclear remodeling

Area of Science:

• Reproductive biology
• Developmental biology
• Cellular reprogramming

Background:

• Somatic cell nuclear transfer (SCNT) relies on cytoplasts to reprogram donor nuclei.
• Maturation promoting factor is crucial for nuclear envelope breakdown (NEBD) and premature chromosome condensation (PCC).
• Previous primate SCNT protocols faced challenges, suggesting issues with nuclear remodeling.

Purpose of the Study:

• To investigate the role of cytoplast-mediated nuclear remodeling in primate SCNT.
• To identify factors hindering efficient reprogramming in conventional SCNT protocols.
• To develop improved SCNT methods for enhanced nuclear remodeling and developmental potential.

Main Methods:

• Monitoring NEBD and PCC in monkey SCNT embryos using lamin A/C immunolabeling.
• Identifying premature cytoplast activation triggers like fluorochrome-assisted enucleation and electrofusion.
• Modifying SCNT protocols to prevent premature cytoplast activation.

Main Results:

• Incomplete NEBD and PCC were linked to developmental arrest in initial SCNT attempts.
• Modified protocols successfully induced robust NEBD and PCC by preventing premature cytoplast activation.
• Over 20% of SCNT embryos developed to blastocysts, with successful Oct-4 expression, indicating effective reprogramming.

Conclusions:

• Nuclear remodeling events are critical for successful reprogramming in SCNT.
• Preventing premature cytoplast activation is key to achieving efficient SCNT in primates.
• This study offers a breakthrough in understanding and improving SCNT techniques.