The CCT chaperonin and actin modulate the ER and RNA-binding protein condensation during oogenesis and maintain translational repression of maternal mRNA and oocyte quality.

The regulation of maternal mRNAs is essential for proper oogenesis, the production of viable gametes, and to avoid birth defects and infertility. Many oogenic RNA-binding proteins have been identified with roles in mRNA metabolism, some of which localize to dynamic ribonucleoprotein granules and others that appear dispersed. Here, we use a combination of in vitro condensation assays and the in vivo oogenesis model to characterize the properties of the conserved KH-domain MEX-3 protein and to identify novel regulators of MEX-3 and three other translational regulators.

The CCT chaperonin and actin modulate the ER and RNA-binding protein condensation during oogenesis to maintain translational repression of maternal mRNA and oocyte quality.

Unlabelled: The regulation of maternal mRNAs is essential for proper oogenesis, the production of viable gametes, and to avoid birth defects and infertility. Many oogenic RNA-binding proteins have been identified with roles in mRNA metabolism, some of which localize to dynamic ribonucleoprotein granules and others that appear dispersed. Here, we use a combination of condensation assays and the oogenesis model to determine the intrinsic properties of the conserved KH-domain MEX-3 protein and to identify novel regulators of MEX-3 and the Lsm protein, CAR-1.

Large RNP granules in Caenorhabditis elegans oocytes have distinct phases of RNA-binding proteins.

The germ line provides an excellent in vivo system to study the regulation and function of RNP granules. Germ granules are conserved germ line-specific RNP granules that are positioned in the Caenorhabditis elegans adult gonad to function in RNA maintenance, regulation, and surveillance. In Caenorhabditis elegans, when oogenesis undergoes extended meiotic arrest, germ granule proteins and other RNA-binding proteins assemble into much larger RNP granules whose hypothesized function is to regulate RNA metabolism and maintain oocyte quality.

Imaging-associated stress causes divergent phase transitions of RNA-binding proteins in the Caenorhabditis elegans germ line.

One emerging paradigm of cellular organization of RNA and RNA-binding proteins is the formation of membraneless organelles. Examples of membraneless organelles include several types of ribonucleoprotein granules that form via phase separation. A variety of intracellular pH changes and posttranslational modifications, as well as extracellular stresses, can stimulate the condensation of proteins into granules.