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Clb2 is a B-type cyclin essential for mitotic progression. Here, the authors found that the CLB2 mRNA localizes to the yeast bud via a cis-acting ZIP-code and She2/She3 transport machinery. This spatial regulation ensures proper cyclin protein levels, whereas its mislocalization perturbs division timing and bud size control.

The ATPase UAP56 acts as an ATP-gated molecular switch that directs mRNA ribonucleoprotein complexes from TREX to nuclear-pore-complex-anchored TREX-2 complexes for mRNA export from the nucleus.

Antisense RNAs boost gene expression by accelerating the export of mRNA from the nucleus to the cytoplasm through the Dbp2-mediated formation of double-stranded RNAs, which might explain the prevalence of antisense RNAs.

Biomolecular condensates are dynamic compartments that regulate cellular functions. Here, the authors show that RNA motifs control the formation and localization of FXR1-containing condensates, linking riboregulation to nuclear pore function and fate transitions in human embryonic stem cells.

UAP56 is an important factor in the TREX complex, which is responsible for mRNA export. Here the authors show that the closely related RNA helicases, UAP56 and URH49, exhibit different three-dimensional structures due to one amino acid change. Accordingly, they form distinct apo-complexes and function in the nuclear export of specific target mRNAs.

The authors discover a homeostatic process termed interstasis, in which an increased concentration of proteins within RNA–protein condensates induces the sequestration of their own mRNAs.

How mitochondria positioning dynamically adapts to changes in cell shape is poorly understood. Here, Bradbury et al. show that cell-size-dependent trafficking of TRAK2 mRNA underpins the cell-size-scaling of mitochondria distribution and activity.

Subcellular mRNA localization is prevalent but with poorly understood physiological roles. Here, the authors show that Net1 mRNA targeting to the basement membrane controls epithelial tissue organization and keratinocyte-stromal connections.

The study introduces NXT2 as a candidate gene for male infertility and shows that the encoded protein is involved in RNA nucleocytoplasmic transport in human testis by interacting with the RNA export factor NXF1 and proteins of the nuclear pore complex. NXT2 also interacts with the human testis-specific NXF1 paralogues NXF2 and NXF3. Mutations in NXT2 and NXF3 are linked to a disruption of nuclear export, leading to defective germ cell development and human male infertility.

Dubiez and colleagues present a cryo-EM structure of the complex responsible for nuclear export of pre-small nuclear RNAs, comprising CBC–PHAX–CRM1–RanGTP. The structure provides insights into the complex architecture, assembly and target RNA recognition.

The DEAD-box ATPase DDX39B (UAP56) plays a critical role in mRNP remodeling and nuclear export. Here, the authors identify TREX-2.1 complex that facilitates DDX39B release from mRNP and reveal the underlying mechanism via cryo-EM structures of TREX-2/DDX39B and TREX-2.1/DDX39B.

Biomolecular condensates are non-membrane-encapsulated compartments that control various biological processes. Recent studies have revealed that condensates change in response to stimuli and over time. This Review discusses the heterogeneity and composition changes of nuclear and cytoplasmic condensates, their regulation and how the changes affect cellular biochemical reactions.

In their study, Dorman and Bendoumou et al., reveal a post-transcriptional regulation of unspliced HIV-1 RNA by host factors MATR3, MTR4, and the viral protein Rev, identifying a previously uncharacterized post-transcriptional block in nucleocytoplasmic export, which plays a crucial role in HIV-1 latency and reactivation.

Bose, Rankovic et al. show that a specific RNA–RNA kissing-loop interaction plays a crucial role in driving biomolecular condensation of ribonucleoprotein granules in the Drosophila germline.

Here the authors study how interactions with nuclear speckles help localize mRNA in cells. They find that modifications of the proteins in these structures affects their cohesion and can modulate mRNA retention under stress.

SNURPORTIN-1, encoded by the SNUPN gene, plays a key role in the nuclear import of spliceosomal small nuclear ribonucleoproteins, however its physiological function remains unclear. Here the authors report that recessive SNUPN mutations cause a distinct subtype of childhood muscular dystrophy and reveal SNURPORTIN-1’s role in muscle homeostasis, offering insights for new therapeutic strategies.

Here, Bhat et al. show that Influenza A virus mRNAs are exported from the nucleus via the nucleoporin Tpr and the mRNA export complex TREX-2. These mRNAs have low exon number, high mean exon length, and low GC content. A 45-nucleotide RNA signal can mediate export via TREX-2.

Aberrant RNA condensates are a hallmark of age-related neurodegenerative diseases. Here, the authors show that RNA condensation increases in aging Drosophila brains, triggering translation repression.

Chromatin remodeler Isw1 prevents export of maturing ribonucleoprotein particles. Here, the authors show that Isw1 inhibits the Unfolded Protein Response (UPR) from the nucleus by binding and restricting export of the mRNA encoding the main effector of UPR, thereby tuning adaptation to ER stress.

There is little information on export directionality of RNA passing through the nuclear pore complex in human cells. Here, the authors examine single RNA molecules in transit, to demonstrate 5’-first directionality for the export of mRNA and lncRNA.

RNA granules are important regulators of RNA metabolism. Here the authors report that RNA granules containing RNA helicase DDX6 disassemble during neuronal maturation.

Circular RNAs are exported from the nucleus by Ran-GTP, exportin-2 and IGF2BP1 in a mechanism analogous to protein export rather than mRNA export.

mRNAs associated with differentiated cells are already detected in adult neural stem cells. Here the authors show how intron detention prevents their translation, solving conflicts in fate decisions while priming stem cells for timely differentiation.

Ribosomal biogenesis is known to require nuclear to cytoplasmic export, but the precise kinetics remain unclear. Here, the authors use super-resolution confocal microscopy and single molecule tracking to visualize export of single pre-60S particles through nuclear pore complexes.

Gene-gating of a MYC oncogenic super-enhancer (OSE) increases its expression in colon cancer cells in a poorly understood process. Here the authors show that MYC gating requires a CTCF binding site (CTCFBS) within the OSE that directs the stepwise trafficking of the OSE to the nuclear pore to facilitate increased nuclear export of MYC mRNA, which results in a growth advantage.

Drp1 is the master regulator of mitochondrial fission, which has important impact on cellular functions. Here, Yang et al identified evolutionarily conserved proteins Clueless and its homolog CLUH as key regulators of Drp1 that function via translation of Drp1 receptors MiD49 and Mff.

Exon junction complexes (EJCs) that mark untranslated mRNA are involved in transport, translation and nonsense-mediated mRNA decay. Here the authors show centrosomal localization of EJCs which appears to be required for both the localization of NIN mRNA around centrosomes and ciliogenesis.

PGC-1α is a master regulator activating the transcription of key genes controlling the cell’s energy production. Here the authors show that PGC-1α has a function in the NXF1-dependent nuclear export of mRNAs.

Large protein complexes and ribonucleoprotein particles (RNPs) such as pre-ribosomes are transported from the nucleus to the cytoplasm through the nuclear pore complex (NPC). Here the authors use ultrafast freezing and electron tomography to catch snapshots of native RNPs crossing the NPC and estimate their transit time using a probabilistic model.

The physiological role of prion-like domains (PLDs) within RNA-binding proteins is not well understood. Here, authors show in Drosophila that the PLD in the protein Imp is required for localization of ribonucleoprotein granules to axons and axonal remodelling.

Fluorogenic RNA aptamers have been used for RNA imaging, but folding and fluorescence stability often limited their use in high resolution applications. Here the authors present an array of stably folding Mango II aptamers for imaging of coding and non-coding RNAs at single-molecule resolution, in both live and fixed cells.

Wang et al. show that mitochondrial stress alters paraspeckle number and morphology through regulating the transcription and processing of lncRNA NEAT1, retaining mRNAs of mitochondrial proteins in paraspeckles.

Asymmetric subcellular mRNA distribution is important for local translation of neuronal mRNAs. Here the authors employed MS2 live-cell imaging and showed that the reporter mRNA containing the 3’ UTR of Rgs4 shows an anterograde transport bias, dependent on neuronal activity and the protein Staufen2, and mediates sustained mRNA recruitment to synapses.

mRNAs export from the nucleus is thought to be regulated in part by three nucleoporins that comprise the nuclear basket, but whether and how distinct basket nucleoporins interact with the RNA export machinery is unclear. Here, the authors use rapid auxin-mediated degradation of basket nucleoporins Nup153, Nup50, and Tpr, and see that Tpr interacts with the TREX-2 mRNA export complex.

The neuronal RNA-binding protein Ptbp2 is known to regulate neuronal differentiation by modulating alternative splicing. Here, the authors reveal an additional role of cytosolic Ptbp2, which regulates axon growth by fine-tuning the mRNA transport and local synthesis of an RNA-binding protein hnRNP R.

RNA localization is mediated by kinesin motors and anchoring. However, mechanisms underlying specificity are unclear. Here, the authors find that MBNL protein’s zinc fingers prefer specific kinesins, and its unstructured tail mediates membrane anchoring.

Crystal structures of a localization element of ASH1 mRNA alone, in complex with its nuclear shuttling protein She2p, and in the cytoplasmic complex with She2p and She3p reveal a step-wise maturation pathway.

The TREX complex and Nxf1 are involved in the export of mRNA from the nucleus but the precise molecular function of TREX is unclear. Here, the TREX components Aly and Thoc5 are shown to bind to Nxf1 resulting in a change in Nxf1 conformation that permits binding to mRNA and nuclear export.

FAPS is a sorting-based method that uses simple sorting controls to purify fluorescently labeled condensates from a cellular lysate. This allows the investigation of condensate biology through characterization of their nucleic acid and protein contents.

Messenger RNAs and their associated proteins are transported from the nucleus through highly selective nuclear pore complexes. Using ultrahigh resolution single-molecule imaging, the authors visualise the path taken by each messenger RNA as it negotiates the pore’s selectivity filter.

The molecular mechanisms regulating axonal mRNA transport are only partially understood. Here, Zhang et al. show a nontelomeric TRF2 splice variant interacts with FMRP to regulate the transport of several axonal mRNAs involved in axonal elongation and neurotransmitter release.

The pre-mRNA splicing and TREX mRNA export machineries are found in nuclear speckle domains. Diaset al. microinject CMV-DNA constructs into cells and find that transcripts containing functional splice sites accumulate in nuclear speckles and that the TREX complex is required to release the mRNA once processed.

The multisubunit TREX-2 complex coordinates transcription and processing of many actively transcribed nascent mRNAs with the recruitment of export factors at nuclear pores. Now the structure of the Sac3–Sem1–Thp1 complex reveals a platform that binds nucleic acids, promoting mRNA export.

Zonal occludens and claudin form tight junctions near the apical surface of cells and are important in polarized epithelia. In this study, the translational regulatory sequence-specific RNA binding protein CPEB is shown to be required for the correct localization of zona occluden 1 mRNA in mammary epithelial cells.

The UCLA Ribonomics group reports that the nuclear export efficiency of innate immune mRNAs varies over a hundred-fold range such that for many genes only a small fraction of the newly synthesized premRNA reaches the cytoplasm. They show that nuclear export and cytoplasmic decay rates are correlated thereby ensuring similar expression levels of short-lived and long-lived mRNAs.

In this study the authors identify localized RNAs in the Drosophila follicular epithelium by spatial transcriptomics and through genetic analyses determine canonical and translation-based mechanisms underlying basal and apical RNA localization.

This study identifies the evolutionarily conserved Exportin 4 as an essential regulator in the nuclear export of circRNAs. Defective circRNA export results in R-loop formation and DNA damage in cells, as well as testis and neurological defects in mice.

Ron and Ulitsky found using massively parallel assays that the effects of short RNA sequences on the subcellular localization of their host RNAs are strongly dependent on the host RNA form, linear or circular, and spliced or unspliced.