Amyloid-like Self-Assembly of a Cellular Compartment

Area of Science:

• Cell Biology
• Developmental Biology
• Biochemistry

Background:

• The Balbiani body is a key organelle in oocytes, essential for germline identity in many vertebrates.
• Its composition and formation mechanism remain largely uncharacterized.
• Xenopus oocytes are a model system for studying early development and germline specification.

Purpose of the Study:

• To investigate the molecular composition and formation of the Balbiani body in Xenopus oocytes.
• To determine the role of the protein Xvelo in Balbiani body assembly.
• To explore the potential conserved mechanism of Balbiani body formation via amyloid-like assembly.

Main Methods:

• Immunofluorescence microscopy to visualize Xvelo localization in Xenopus oocytes.
• Biochemical assays using recombinant Xvelo to study its self-assembly properties in vitro.
• RNA and mitochondria binding assays with Xvelo assemblies.

Main Results:

• Xvelo, a protein with a prion-like domain, is a major component of the Xenopus Balbiani body.
• Disruption or substitution of Xvelo's prion-like domain impairs its incorporation into Balbiani bodies.
• Recombinant Xvelo forms amyloid-like networks in vitro that recruit RNA and mitochondria.

Conclusions:

• Xenopus Balbiani bodies are proposed to form through the amyloid-like assembly of Xvelo.
• This assembly process facilitates the co-recruitment of essential components like RNA and mitochondria.
• Amyloid-like assembly of germ plasm organizing proteins may be a conserved mechanism for maintaining oocyte function and germ cell longevity.