PGL germ granule assembly protein is a base-specific, single-stranded RNase.

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Cellular RNA-protein (RNP) granules are crucial for RNA metabolism but their assembly and function lack molecular understanding.
• P-granules in nematodes serve as a model system for studying RNP granule structure and dynamics.

Purpose of the Study:

• To elucidate the molecular basis of RNP granule assembly using the PGL protein scaffold.
• To investigate the structure, function, and assembly mechanisms of P-granule components.

Main Methods:

• Crystal structure determination of the PGL dimerization domain (DD).
• Biochemical assays to assess RNA binding and enzymatic activity of PGL-1 DD.

Main Results:

• Identified and determined the crystal structure of the PGL-1 DD, revealing a novel 13 α-helix fold forming a homodimer with a charged channel.
• Discovered that PGL-1 DD possesses guanosine-specific, single-stranded endonuclease activity.
• Proposed a model where the PGL DD dimer is a fundamental building block for P-granule assembly.

Conclusions:

• The PGL DD dimer serves as a structural unit for P-granule assembly.
• PGL proteins possess enzymatic activity (RNase), expanding their known roles beyond structural scaffolding in RNP granules.