Exit from totipotency in mammals: an epigenetic perspective

Area of Science:

• Developmental Biology
• Genomics
• Epigenetics

Background:

• Totipotency is the unique ability of a single cell to differentiate into a complete organism, characteristic of early embryonic stages.
• Zygotic genome activation (ZGA) marks the transition from maternal to embryonic gene expression, coinciding with the loss of totipotency.
• Efficient silencing of totipotency-associated genes during ZGA is critical for normal embryonic development, yet the underlying mechanisms are poorly understood.

Purpose of the Study:

• To review the overlooked mechanisms controlling the transient expression of totipotent-associated genes during ZGA in mice.
• To discuss the conservation of these regulatory mechanisms in human embryonic development.

Main Methods:

• This review synthesizes existing literature on ZGA and totipotency.
• Focuses on molecular and genetic studies in mouse models.
• Compares findings with available data on human embryonic development.

Main Results:

• ZGA involves a tightly regulated transcriptional program associated with totipotency.
• The timely silencing of this program is essential for the exit from totipotency and subsequent development.
• Specific molecular players governing this transient expression remain to be fully elucidated.

Conclusions:

• Understanding the regulation of transient gene expression during ZGA is key to comprehending totipotency loss.
• Investigating these mechanisms in mice provides insights into conserved processes in human development.
• Further research is needed to identify the precise molecular regulators involved.