Tdrd6a and Tdrd6b are required together for germ plasm formation.

Area of Science:

• Developmental Biology
• Cell Biology
• Genetics

Background:

• Germ cell specification relies on germplasm (Gp), which are phase-separated structures formed by maternal factors.
• In zebrafish, the Balbiani body (Bb) is a key Gp structure essential for oocyte polarization.
• Regulation of Gp formation, particularly in vertebrates, is not fully understood.

Purpose of the Study:

• To investigate the roles of Tdrd6a and Tdrd6b in germplasm formation and germ cell development in zebrafish.
• To elucidate the molecular mechanisms underlying Gp regulation by these proteins.

Main Methods:

• Genetic analysis of Tdrd6a and Tdrd6b knockout zebrafish.
• Microscopy to observe germplasm and Balbiani body formation.
• Biochemical assays to study protein interactions and domain functions.

Main Results:

• Tdrd6a and Tdrd6b are collectively essential for germplasm formation in zebrafish.
• Loss of both proteins leads to dispersed germplasm at the 4-cell stage, resulting in absent primordial germ cells and sterility.
• The prion-like domain of Tdrd6b is critical for its aggregation and interaction with Buc, modulated by its Tudor domains.

Conclusions:

• Tdrd6a and Tdrd6b play a vital, coordinated role in maintaining germplasm stability during zebrafish development.
• Understanding the function of Tdrd6a and Tdrd6b provides insights into the regulation of phase-separated structures crucial for germ cell development.