Molecular Dissection of a Caenorhabditis Elegans Germ Granule Assembly Protein to Determine Its Role in Cell Development

In metazoans, germ cells play a fundamental role in ensuring the continuity of animal life. Germ cells contain germ granules, cytoplasmic non-membrane bound organelles also referred to as RNA-protein condensates. These germ granules house a variety of RNAs and proteins essential for germline identity, maintenance, and fertility. In C. elegans, P granules are a specific type of germ granule that localize to the nuclear periphery of developing germ cells and regulate mRNA expression. Proper P granule assembly is dependent on the PGL family of granule forming proteins, with PGL-1 serving as a key component containing two dimerization domains and a C-terminal region. Numerous proteins localize to P granules, most of which are RNA-binding or regulatory proteins. For instance, IFE- 1, an eIF4E family member that binds the 5’ cap of mRNAs, directly interacts with PGL-1 in vivo and in vitro, and localizes to P granules. The precise molecular function of PGL and their associated proteins remains unclear; they may act solely as granule assembly proteins, serve as scaffolds to recruit other proteins, or directly regulate RNA. To better understand these roles, microscopy, biochemistry, and molecular genetic methods were utilized to molecularly dissect PGL-1 in vivo to probe how different protein regions are required for granule assembly, P granule binding partner recruitment, and germ cell development. First, it determined a previously uncharacterized role for the PGL-1 Ct region in IFE-1 recruitment and granule formation. Second, it determined direct RNA targets bound to IFE-1. Third, it provided direct evidence that IFE-1 associated mRNAs are repressed and that this repressive function is dependent on PGL-1 association. Together, these findings support a model where IFE-1 is recruited to P granules by directly binding the PGL-1 C-terminus to repress its mRNA targets for germ cell development. Our study provides novel insights into the molecular mechanisms governing P granule protein interactions, highlighting their essential biological relevance and potential impact on understanding germ cell development.

Author dc:creator

• Herrera Sandoval, Carmen

Advisor dc:contributor.advisor

• Aoki, Scott T.

Language dc:language.iso

en_US

Identifier URI

https://doi.org/10.7912/YH0D-CG61

OAI identifier oai:identifier

oai:scholarworks.indianapolis.iu.edu:1805/52917