RNA sample optimization for cryo-EM analysis.

RNAs play critical roles in most biological processes. Although the three-dimensional (3D) structures of RNAs primarily determine their functions, it remains challenging to experimentally determine these 3D structures due to their conformational heterogeneity and intrinsic dynamics. Cryogenic electron microscopy (cryo-EM) has recently played an emerging role in resolving dynamic conformational changes and understanding structure-function relationships of RNAs including ribozymes, riboswitches and bacterial and viral noncoding RNAs.

Unravelling the potential of yolkin for nutraceutical use: the origin, structure, and functional insights of a hen egg yolk polypeptide complex.

Nutraceuticals can reduce the risk of many diseases, such as cardiovascular disease, immune deficiencies, neurodegeneration, and others. Their delivery remains a challenge because it depends on many factors, most notably the stability of the bioactive compounds. Yolkin is a peptide complex isolated from hen egg yolk with immunomodulatory and neuroprotective potential.

RNA-binding activity of TRIM25 is mediated by its PRY/SPRY domain and is required for ubiquitination.

Background: TRIM25 is a novel RNA-binding protein and a member of the Tripartite Motif (TRIM) family of E3 ubiquitin ligases, which plays a pivotal role in the innate immune response. However, there is scarce knowledge about its RNA-related roles in cell biology. Furthermore, its RNA-binding domain has not been characterized.

Lin28a uses distinct mechanisms of binding to RNA and affects miRNA levels positively and negatively.

Lin28a inhibits the biogenesis of let-7 miRNAs by triggering the polyuridylation and degradation of their precursors by terminal uridylyltransferases TUT4/7 and 3'-5' exoribonuclease Dis3l2, respectively. Previously, we showed that Lin28a also controls the production of neuro-specific miRNA-9 via a polyuridylation-independent mechanism. Here we reveal that the sequences and structural characteristics of pre-let-7 and pre-miRNA-9 are eliciting two distinct modes of binding to Lin28a.

Trim25 Is an RNA-Specific Activator of Lin28a/TuT4-Mediated Uridylation.

RNA binding proteins have thousands of cellular RNA targets and often exhibit opposite or passive molecular functions. Lin28a is a conserved RNA binding protein involved in pluripotency and tumorigenesis that was previously shown to trigger TuT4-mediated pre-let-7 uridylation, inhibiting its processing and targeting it for degradation. Surprisingly, despite binding to other pre-microRNAs (pre-miRNAs), only pre-let-7 is efficiently uridylated by TuT4.

Lin28a regulates neuronal differentiation and controls miR-9 production.

microRNAs shape the identity and function of cells by regulating gene expression. It is known that brain-specific miR-9 is controlled transcriptionally; however, it is unknown whether post-transcriptional processes contribute to establishing its levels. Here we show that miR-9 is regulated transcriptionally and post-transcriptionally during neuronal differentiation of the embryonic carcinoma cell line P19.

Silica nanoparticle uptake induces survival mechanism in A549 cells by the activation of autophagy but not apoptosis.

We report here an in vitro evaluation of silica nanoparticle uptake by lung epithelial cells (A549), the cytotoxic effect of the particles and we propose autophagy as possible survival strategy. The effect of surface charge, serum proteins and the influence of inhibitors on the uptake of 20 nm monodispersed nanoparticles with various functional groups are discussed. Uptake rate of the particles with various functional groups is demonstrated to be similar in the presence of serum proteins, while the uptake rate ranking is COOH>NH2>OH under serum free conditions.

miRNAs in development and pathogenesis of the nervous system.

The human nervous system expresses approximately 70% of all miRNAs (microRNAs). Changing levels of certain ubiquitous and brain-specific miRNAs shape the development and function of the nervous system. It is becoming clear that misexpression of some miRNAs can contribute towards neurodevelopmental disorders.