Exogenous OCT4 and SOX2 Contribution to In Vitro Reprogramming in Cattle.

Area of Science:

• Cell Biology
• Developmental Biology
• Genetics

Background:

• Pluripotency-related transcription factors like OCT4 and SOX2 are crucial for cell reprogramming.
• Somatic cell nuclear transfer (SCNT) is a key technique for generating cloned embryos and studying reprogramming.
• Understanding the interplay between transcription factors and SCNT is vital for advancing regenerative medicine.

Purpose of the Study:

• To investigate the role of OCT4 and SOX2 in bovine cell reprogramming and SCNT.
• To analyze the impact of exogenous OCT4 and SOX2 expression on pluripotency and imprinted genes.
• To compare the efficiency of in vitro reprogramming and SCNT using cells with varying pluripotency factor expression.

Main Methods:

• Bovine fibroblasts were engineered to express OCT4, SOX2, or both.
• Gene expression analysis of pluripotency factors and imprinted genes (H19, IGF2R) was performed.
• In vitro reprogramming and SCNT experiments were conducted using sorted and unsorted donor cells.
• Embryo development rates (fusion, cleavage, blastocyst) were assessed after SCNT.

Main Results:

• Exogenous OCT4 and SOX2 expression altered pluripotency gene profiles, with H19 expression increasing in sorted cells.
• Putative induced pluripotent stem-like cells were generated when cells were not sorted prior to reprogramming.
• SCNT using sorted OCT4 or SOX2-expressing cells yielded comparable fusion, cleavage, and blastocyst rates to control cells.
• In vitro reprogramming efficiency was compromised in sorted cells compared to unsorted cells.

Conclusions:

• While OCT4 and SOX2 play roles in cellular reprogramming, their exogenous expression does not significantly alter SCNT-derived embryo developmental competence in vitro.
• Cell sorting prior to SCNT can negatively impact induced reprogramming, suggesting a need for optimized protocols.
• The study highlights the complex mechanisms underlying pluripotency and reprogramming, with implications for future stem cell research and therapeutic applications.