AGO1 controls protein folding in mouse embryonic stem cell fate decisions.

Argonaute (AGO) proteins are evolutionarily conserved RNA-binding proteins that control gene expression through the small RNAs they interact with. Whether AGOs have regulatory roles independent of RNAs, however, is unknown. Here, we show that AGO1 controls cell fate decisions through facilitating protein folding.

Different congenital hydrocephalus-associated mutations in Trim71 impair stem cell differentiation via distinct gain-of-function mechanisms.

Congenital hydrocephalus (CH) is a common neurological disorder affecting many newborns. Imbalanced neurogenesis is a major cause of CH. Multiple CH-associated mutations are within the RNA-binding domain of Trim71, a conserved, stem cell-specific RNA-binding protein.

A congenital hydrocephalus-causing mutation in Trim71 induces stem cell defects via inhibiting Lsd1 mRNA translation.

Congenital hydrocephalus (CH) is a major cause of childhood morbidity. Mono-allelic mutations in Trim71, a conserved stem-cell-specific RNA-binding protein, cause CH; however, the molecular basis for pathogenesis mediated by these mutations remains unknown. Here, using mouse embryonic stem cells as a model, we reveal that the mouse R783H mutation (R796H in human) alters Trim71's mRNA substrate specificity and leads to accelerated stem-cell differentiation and neural lineage commitment.

microRNA-mediated regulation of microRNA machinery controls cell fate decisions.

microRNAs associate with Argonaute proteins, forming the microRNA-induced silencing complex (miRISC), to repress target gene expression post-transcriptionally. Although microRNAs are critical regulators in mammalian cell differentiation, our understanding of how microRNA machinery, such as the miRISC, are regulated during development is still limited. We previously showed that repressing the production of one Argonaute protein, Ago2, by Trim71 is important for mouse embryonic stem cells (mESCs) self-renewal (Liu et al.

Repressing mRNA translation by Trim71 maintains pluripotency through inhibiting let-7 microRNAs.

The regulation of stem cell fate is poorly understood. Genetic studies in lead to the hypothesis that a conserved cytoplasmic double-negative feedback loop consisting of the RNA-binding protein Trim71 and the let-7 microRNA controls the pluripotency and differentiation of stem cells. Although let-7-microRNA-mediated inhibition of Trim71 promotes differentiation, whether and how Trim71 regulates pluripotency and inhibits the let-7 microRNA are still unknown.