Mitochondrial transfer RNA mutation is one of the most important causes of hereditary hearing loss in humans. Mitochondrial transfer RNASer (UCN) gene is another hot spot for mutations associated with non-syndromic hearing loss, besides the 12S ribosomal RNA gene. In this study, we assessed the clinical phenotype and the molecular characteristics of two Chinese families with non-syndromic hearing loss. Mutational analysis revealed that 7445A > G and 7510T > C mutations in the mitochondrial transfer RNASer (UCN) gene were the molecular etiology of Family 1 and Family 2, respectively. However, the clinical and genetic characteristics of the two families carrying the above mutations in the transfer RNASer (UCN) gene exhibited a variable expression of hearing loss and an incomplete penetrance. Sequencing analysis of the complete mitochondrial genome showed the presence of transfer RNATrp 5568A > G and NADH-ubiquinone oxidoreductase chain 4 11696G > A mutations in Family 1. The mitochondrial haplotype analysis showed that the two families belonged to Asian D4 and M80\'D haplotypes, respectively, and no pathogenic variations were found in the nuclear genes. To our knowledge, our study is the first to report 7445A > G and 7510T > C mutations in the mitochondrial transfer RNASer (UCN) gene, in multi-generation non-syndromic hearing loss pedigrees from China. Our study suggests that 5568A > G and 11696G > A mutations may enhance the penetrance of hearing loss in Chinese Family 1, while mitochondrial haplotypes and known nuclear genes may not be modifiers for the phenotypic expression of 7445A > G and 7510T > C mutations in these Chinese families.

UNASSIGNED: The relationship between placental pathology and the maternal syndrome of preeclampsia is incompletely characterized. Mismatch between placental nutrient supply and fetal demands induces stress in the syncytiotrophoblast, the layer of placenta in direct contact with maternal blood. Such stress alters the content and increases the release of syncytiotrophoblast extracellular vesicles (STB-EVs) into the maternal circulation. We have previously shown 5\'-tRNA fragments (5\'-tRFs) constitute the majority of small RNA in STB-EVs in healthy pregnancy. 5\'-tRFs are produced in response to stress. We hypothesized STB-EV 5\'-tRF release might change in preeclampsia.
UNASSIGNED: We perfused placentas from 8 women with early-onset preeclampsia and 6 controls, comparing small RNA expression in STB-EVs. We used membrane-affinity columns to isolate maternal plasma vesicles and investigate placental 5\'-tRFs in vivo. We quantified 5\'-tRFs from circulating STB-EVs using a placental alkaline phosphatase immunoassay. 5\'-tRFs and scrambled RNA controls were added to monocyte, macrophage and endothelial cells in culture to investigate transcriptional responses.
UNASSIGNED: 5\'-tRFs constitute the majority of small RNA in STB-EVs from both preeclampsia and normal pregnancies. More than 900 small RNA fragments are differentially expressed in preeclampsia STB-EVs. Preeclampsia-dysregulated 5\'-tRFs are detectable in maternal plasma, where we identified a placentally derived load. 5\'-tRF-Glu-CTC, the most abundant preeclampsia-upregulated 5\'-tRF in perfusion STB-EVs, is also increased in preeclampsia STB-EVs from maternal plasma. 5\'-tRF-Glu-CTC induced inflammation in macrophages but not monocytes. The conditioned media from 5\'-tRF-Glu-CTC-activated macrophages reduced eNOS (endothelial NO synthase) expression in endothelial cells.
UNASSIGNED: Increased release of syncytiotrophoblast-derived vesicle-bound 5\'-tRF-Glu-CTC contributes to preeclampsia pathophysiology.

Megalurothrips usitatus (Bagnall, 1913) (Thysanoptera: Thripidae) is a widely distributed pest in Asia that primarily affects the production of snap beans and cowpea. The complete mitochondrial genome of Megalurothrips usitatus has been sequenced and annotated in this study, which is 17,209 bp long and contains 13 protein-coding genes (PCGs), two rRNAs, and 22 tRNA genes. Most of the protein-coding genes (PCGs) start with ATG except ND4 using TTG. Meanwhile, eight PCGs stop with TAA, four PCGs have an incomplete stop codon, and the gene Cytb ends with TAG. Phylogenetic analysis showed that M. usitatus is closely related to Frankliniella intonsa and F. occidentalis, providing a basis for the study of the mitochondrial evolution of Thripinae.

The precise coupling of tRNAs with their cognate amino acids, known as tRNA aminoacylation, is a stringently regulated process that governs translation fidelity. To ensure fidelity, organisms deploy multiple layers of editing mechanisms to correct mischarged tRNAs. Prior investigations have unveiled the propensity of eukaryotic AlaRS to erroneously attach alanine onto tRNACys and tRNAThr featuring the G4:U69 base pair. In light of this, and given ProXp-ala\'s capacity in deacylating Ala-tRNAPro, we embarked on exploring whether this trans-editing factor could extend its corrective function to encompass these mischarged tRNAs. Our in vitro deacylation assays demonstrate that murine ProXp-ala (mProXp-ala) is able to efficiently hydrolyze Ala-tRNAThr, while Ala-tRNACys remains unaffected. Subsequently, we determined the first structure of eukaryotic ProXp-ala, revealing a dynamic helix α2 involved in substrate binding. By integrating molecular dynamics simulations and biochemical assays, we pinpointed the pivotal interactions between mProXp-ala and Ala-tRNA, wherein the basic regions of mProXp-ala as well as the C3-G70 plays essential role in recognition. These observations collectively provide a cogent rationale for mProXp-ala\'s deacylation proficiency against Ala-tRNAThr. Our findings offer valuable insights into the translation quality control within higher eukaryotic organisms, where the fidelity of translation is safeguarded by the multi-functionality of extensively documented proteins.

The present study reports the mitochondrial genome of A. hastata (Oberthür, 1892), a little-known Aporia species endemic to the southern margin of the Hengduan Mountains in Yunnan Province. This genome is circular, 15,148 bp in length, and consists of 13 PCGs, 22 tRNAs, and two rRNAs. The Bayesian phylogenetic tree clusters A. hastata with other Aporia taxa inside tribe Pierini Duponchel, [1835]. The findings of this study add valuable new information to the genus Aporia and are beneficial to a better understanding of phylogeography of these butterflies.

Manipulating transfer RNAs (tRNAs) for emancipating sense codons to simplify genetic codons in a cell-free protein synthesis (CFPS) system can offer more flexibility and controllability. Here, we provide an overview of the tRNA complement protein synthesis system construction in the tRNA-depleted Protein synthesis Using purified Recombinant Elements (PURE) system or S30 extract. These designed polypeptide coding sequences reduce the genetic codon and contain only a single tRNA corresponding to a single amino acid in this presented system. Strategies for removing tRNAs from cell lysates and synthesizing tRNAs in vivo/vitro are summarized and discussed in detail. Furthermore, we point out the trend toward a minimized genetic codon for reducing codon redundancy by manipulating tRNAs in the different proteins. It is hoped that the tRNA complement protein synthesis system can facilitate the construction of minimal cells and expand the biomedical application scope of synthetic biology.

The cellular response to stress is an important determinant of disease pathogenesis. Uncovering the molecular fingerprints of distinct stress responses may identify novel biomarkers and key signaling pathways for different diseases. Emerging evidence shows that transfer RNA-derived small RNAs (tDRs) play pivotal roles in stress responses. However, RNA modifications present on tDRs are barriers to accurately quantifying tDRs using traditional small RNA sequencing. Here, AlkB-facilitated methylation sequencing is used to generate a comprehensive landscape of cellular and extracellular tDR abundances in various cell types during different stress responses. Extracellular tDRs are found to have distinct fragmentation signatures from intracellular tDRs and these tDR signatures are better indicators of different stress responses than miRNAs. These distinct extracellular tDR fragmentation patterns and signatures are also observed in plasma from patients on cardiopulmonary bypass. It is additionally demonstrated that angiogenin and RNASE1 are themselves regulated by stressors and contribute to the stress-modulated abundance of sub-populations of cellular and extracellular tDRs. Finally, a sub-population of extracellular tDRs is identified for which AGO2 appears to be required for their expression. Together, these findings provide a detailed profile of stress-responsive tDRs and provide insight about tDR biogenesis and stability in response to cellular stressors.

Graphium (Pazala) confucius Hu, Duan & Cotton, 2018 is a recently discovered, wide ranging, multivoltine swordtail butterfly in China and Vietnam. The present study reports the complete mitochondrial genome of this butterfly, which is the fifth mitochondrial genome record for subgenus Pazala Moore, 1888. The mitochondrial genome of G. (P.) confucius is circular and 15,212 bp in length, and consists of 37 genes, including 13 PCGs, 22 tRNAs, and two rRNAs. The Bayesian phylogenetic tree containing the focal species and 33 other Papilioninae members clusters G. (P.) confucius with other Pazala taxa inside tribe Leptocircini, which agrees with its taxonomic position. The findings of this study added data to the complex subgenus Pazala and are beneficial to future understanding and conservation planning of butterfly diversity.

The dysregulation of transfer RNA (tRNA) expression contributes to the diversity of proteomics, heterogeneity of cell populations, and instability of the genome, which may be related to human cancer susceptibility. However, the relationship between tRNA dysregulation and cancer susceptibility remains elusive because the landscape of cancer-associated tRNAs has not been portrayed yet. Furthermore, the molecular mechanisms of tRNAs involved in tumorigenesis and cancer progression have not been systematically understood. In this review, we detail current knowledge of cancer-related tRNAs and comprehensively summarize the basic characteristics and functions of these tRNAs, with a special focus on their role and involvement in human cancer. This review bridges the gap between tRNAs and cancer and broadens our understanding of their relationship, thus providing new insights and strategies to improve the potential clinical applications of tRNAs for cancer diagnosis and therapy.

Emerging evidence suggests that majority of the transfer RNA (tRNA)-derived small RNA, including tRNA-derived fragments (tRFs) and tRNA halves (tiRNAs), play a significant role in the molecular mechanisms underlying some human diseases. However, expression of tRFs/tiRNAs and their potential roles in aortic dissection (AD) remain unclear. This study examined the expression characteristics and explored the functional roles of tRFs/tiRNAs in AD using RNA-sequencing, bioinformatics, real-time quantitative reverse transcription polymerase chain reaction, and loss- and gain-of-function analysis. Results revealed that a total of 41 tRFs/tiRNAs were dysregulated in the AD group compared to the control group. Among them, 12 were upregulated and 29 were downregulated (fold change≥1.5 and p < 0.05). RT-qPCR results revealed that expressions of tRF-1:30-chrM.Met-CAT was significantly upregulated, while that of tRF-54:71-chrM.Trp-TCA and tRF-1:32-chrM.Cys-GCA were notably downregulated; expression patterns were consistent with the RNA sequencing data. Bioinformatic analysis showed that a variety of related pathways might be involved in the pathogenesis of AD. Functionally, tRF-1:30-chrM.Met-CAT could facilitate proliferation, migration, and phenotype switching in vascular smooth muscle cells (VSMCs), which might serve as a significant regulator in the progression of AD. In summary, the study illustrated that tRFs/tiRNAs expressed in AD tissues have potential biological functions and may act as promising biomarkers or therapeutic targets for AD.