Subcytoplasmic location of translation controls protein output

Quantifying 3'UTR length from scRNA-seq data reveals changes independent of gene expression

Although more than half of all genes generate transcripts that differ in 3'UTR length, current analysis pipelines only quantify the amount but not the length of mRNA transcripts. 3'UTR length is determined by 3' end cleavage sites (CS). We map CS in more than 200 primary human and mouse cell types and increase CS annotations relative to the GENCODE database by 40%. Approximately half of all CS are used in few cell types, revealing that most genes only have one or two major 3' ends. We incorporate the CS annotations into a computational pipeline, called scUTRquant, for rapid, accurate, and simultaneous quantification of gene and 3'UTR isoform expression from single-cell RNA sequencing (scRNA-seq) data. When applying scUTRquant to data from 474 cell types and 2134 perturbations, we discover extensive 3'UTR length changes across cell types that are as widespread and coordinately regulated as gene expression changes but affect mostly different genes. Our data indicate that mRNA abundance and mRNA length are two largely independent axes of gene regulation that together determine the amount and spatial organization of protein synthesis.

Endoplasmic reticulum - condensate interactions in protein synthesis and secretion

In the past decade, a growing amount of evidence has demonstrated that organelles do not act autonomously and independently but rather communicate with each other to coordinate different processes for proper cellular function. With a highly extended network throughout the cell, the endoplasmic reticulum (ER) plays a central role in interorganelle communication through membrane contact sites. Here, we highlight recent evidence indicating that the ER also forms contacts with membrane-less organelles. These interactions contribute to the dynamic assembly and disassembly of condensates and controlled protein secretion. Additionally, emerging evidence suggests their involvement in mRNA localization and localized translation. We further explore exciting future directions of this emerging theme in the organelle contact site field.

Bibliometric Overview on T-Cell Intracellular Antigens and Their Pathological Implications

T-cell intracellular antigen 1 (TIA1) and TIA1-like/related protein (TIAL1/TIAR) are two members of the classical family of RNA binding proteins. Through their selective interactions with distinct RNAs and proteins, these multifunctional regulators are involved in chromatin remodeling, RNA splicing and processing and translation regulation, linking them to a wide range of diseases including neuronal disorders, cancer and other pathologies. From their discovery to the present day, many studies have focused on the behavior of these proteins in order to understand their impact on molecular and cellular processes and to understand their relationship to human pathologies. The volume of research on these proteins in various fields, including molecular biology, biochemistry, cell biology, immunology and cancer, has steadily increased, indicating a growing interest in these gene expression regulators among researchers. This information can be used to know the most productive institutions working in the field, understand the focus of research, identify key areas of involvement, delve deeper into their relationship and impact on different diseases, and to establish the level of study associated with them.

FMRP-mediated spatial regulation of physiologic NMD targets in neuronal cells

In non-polarized cells, nonsense-mediated mRNA decay (NMD) generally begins during the translation of newly synthesized mRNAs after the mRNAs are exported to the cytoplasm. Binding of the FMRP translational repressor to UPF1 on NMD targets mainly inhibits NMD. However, in polarized cells like neurons, FMRP additionally localizes mRNAs to cellular projections. Here, we review the literature and evaluate available transcriptomic data to conclude that, in neurons, the translation of physiologic NMD targets bound by FMRP is partially inhibited until the mRNAs localize to projections. There, FMRP displacement in response to signaling induces a burst in protein synthesis followed by rapid mRNA decay.