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In eukaryotes, RNAs transcribed by RNA Pol II are modified at the 5' end with a 7-methylguanosine (m7G) cap, which is recognized by the nuclear cap binding complex (CBC). The CBC plays multiple important roles in mRNA metabolism, including transcription, splicing, polyadenylation, and export. It promotes mRNA export through direct interaction with a key mRNA export factor, ALYREF, which in turn links the TRanscription and EXport (TREX) complex to the 5' end of mRNA. However, the molecular mechanism for CBC-mediated recruitment of the mRNA export machinery is not well understood. Here, we present the first structure of the CBC in complex with an mRNA export factor, ALYREF. The cryo-EM structure of CBC-ALYREF reveals that the RRM domain of ALYREF makes direct contact with both the NCBP1 and NCBP2 subunits of the CBC. Comparing CBC-ALYREF with other cellular complexes containing CBC and/or ALYREF components provides insights into the coordinated events during mRNA transcription, splicing, and export.

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5-Fluorouracil (5-FU) has been used for chemotherapy for colorectal and other cancers for over 50 years. The prevailing view of its mechanism of action is inhibition of thymidine synthase leading to defects in DNA replication and repair. However, 5-FU is also incorporated into RNA causing defects in RNA metabolism, inhibition of pseudouridine modification, and altered ribosome function. We examined the impact of 5-FU on post-transcriptional small RNA modifications (PTxMs) and the expression and export of RNA into small extracellular vesicles (sEVs). EVs are secreted by all cells and contain a variety of proteins and RNAs that can function in cell-cell communication. We found that treatment of colorectal cancer (CRC) cells with 5-FU represses sEV export of miRNA and snRNA-derived RNAs, but promotes export of snoRNA-derived RNAs. Strikingly, 5-FU treatment significantly decreased the levels of pseudouridine on both cellular and sEV small RNA profiles. In contrast, 5-FU exposure led to increased levels of cellular small RNAs containing a variety of methyl-modified bases. These unexpected findings show that 5-FU exposure leads to altered RNA expression, base modification, and aberrant trafficking and localization of small RNAs.

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Rising global oil prices are a major challenge for an emerging oil-importing nation such as Bangladesh. The majority of prior research on the economic effects of an oil price shock has concentrated on developed countries, with emerging economies receiving comparatively less attention. Bangladesh is vulnerable to price shocks due to its rising oil consumption over the past decade. This study aims to investigate how changes in oil prices would affect Bangladesh's total export earnings and to forecast the overall export volume. This study utilized a nonlinear autoregressive distributed lag (NARDL) approach to account for the asymmetric behavior of oil prices from 1991 to 2021. To assess the accuracy of predictions, the study employed the Prophet forecasting model and the Long Short-Term Memory (LSTM) method. Additionally, the symmetry test revealed a nonlinear relationship between export volume and oil price but a linear relationship between inflation and export volume. According to the NARDL assessment, both positive and negative oil shocks increase export earnings over the long run. The short run summary clarifies that both positive and negative changes in oil prices exert a significant negative effect on exports. Also, Inflation influences export earnings negatively in the short run but positively over the long term. Moreover, using machine learning methods, it was found that the LSTM method outperforms the prophet model in prediction performance with a low root mean square error (RMSE) of 1.88. Also, the analysis revealed policymakers that the export sector requires diversification to reduce its exposure to oil price shocks.

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The transcription and transportation of mRNA are coupled processes; however, the mechanisms linking these processes remain unclear. Additionally, the significance of this connection in cancer drug development is poorly understood. To address these issues, we investigated the role of CDK12 kinase, which regulates RNA transcription through the phosphorylation of RNA polymerase II (Pol II) and has a repeated serine-arginine dipeptide (RS domain) involved in mRNA transport. Despite the anticipated uniqueness of CDK12 function, the mechanism by which CDK12 bridges and manages mRNA transcription and transport has not been fully analyzed. Our study revealed that CDK12 interacts with NXF1, a key molecule involved in the export of mRNA from the nucleus to the cytosol. Although CDK12 does not phosphorylate NXF1, we found that NXF1 unexpectedly stabilized the CDK12 protein, suggesting that NXF1 mRNA export activity indirectly affects mRNA transcriptional activity by modifying the protein level of CDK12. Furthermore, CDK12 recruited other essential RNA transporters, specifically the exon junction complex (EJC) and THO complexes, into the CDK12-NXF1 axis through its kinase activity. These observations provide insights into the mechanisms linking mRNA transcription and transport through the formation of a novel CDK12-NXF1 complex that involves EJC and THO. Importantly, the expression level of NXF1 influences sensitivity to CDK12 inhibitors, which are emerging as novel anti-cancer drug candidates. This highlights the importance of considering the relationship between mRNA transcription and transport when targeting RNA transcription in cancer therapy.

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Scientific evidence has revealed that climate change negatively affects agricultural crop production both regionally and globally. Previous studies have indicated that the role of climate change is significant in some parts of China. Thus, assessing the impact of the future climate on the grain market is vital for ensuring regional and national food security. In this study, regional climate model (RCM 4.5 and 8.5) simulations were employed to investigate the role of future climate change on a major grain-producing market in China (Northeast China). For this purpose, historical (2004-2017) and future (2020-2076) data were applied in the gravity model to examine the effects of climate change on the Northeast China grain market. The results revealed that the maximum temperature is a crucial climate factor that significantly affects the grain market. The analysis revealed that precipitation was positively related and that the temperature was significantly negatively related to domestic consumption and exports of rice, maize, and soybean. Moreover, the analysis of the RCM (4.5 and 8.5) simulations revealed a negative contribution of the maximum temperature to domestic consumption and export levels. Overall, the analysis enhances our understanding of the impacts of climate change on the Northeast China grain market.

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Collagen is the most abundant protein in the extracellular matrix of animals, and 28 types of collagen have been reported in humans. We previously analyzed the endoplasmic reticulum (ER)-to-Golgi transport of fibril-forming type III collagen (Hirata et al. 2022) and network-forming type IV collagen (Matsui et al. 2020), both of which have long collagenous triple-helical regions. To understand the ER-to-Golgi trafficking of various types of collagens, we analyzed the transport of short-chain type X collagen in this study. We fused cysteine-free GFP to the N-telopeptide region of procollagen X (GFP-COL10A1), as employed in our previous analysis of procollagens III and IV, and analyzed its transport by live-cell imaging. Procollagen X was transported to the Golgi apparatus via vesicular and tubular carriers containing ERGIC53 and RAB1B, similar to those used for procollagen III. Carriers containing procollagen X probably used the same transport processes as those containing conventional cargoes such as ⍺1-antitrypsin. SAR1, TANGO1, SLY1/SCFD1, and BET3/TRAPPC3 were required for trafficking of procollagen X, which are different from the factors required for trafficking of procollagens III (SAR1, TANGO1, and CUL3) and IV (SAR1 and SLY1/SCFD1). These findings reveal that accommodation of various types of collagens with different shapes into carriers may require fine-tuning of the ER-to-Golgi transport machinery.Key words: collagen, GFP-procollagen X, ER-to-Golgi trafficking, export from ER, TANGO1.

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In eukaryotic cells, gene expression begins with transcription in the nucleus, followed by the maturation of messenger RNAs (mRNAs). These mRNA molecules are then exported to the cytoplasm through the nuclear pore complex (NPC), a process that serves as a critical regulatory phase of gene expression. The export of mRNA is intricately linked to precursor mRNA (pre-mRNA) processing, ensuring that only properly processed mRNA reaches the cytoplasm. This coordination is essential, as recent studies have revealed that mRNA export factors not only assist in transport but also influence upstream processing steps, adding a layer of complexity to gene regulation. Furthermore, the export process competes with RNA processing and degradation pathways, maintaining a delicate balance vital for accurate gene expression. While these mechanisms are generally conserved across eukaryotes, significant differences exist between yeast and higher eukaryotic cells, particularly due to the more genome complexity of the latter. This review delves into the current research on mRNA export in higher eukaryotic cells, focusing on its role in the broader context of gene expression regulation and highlighting how it interacts with other gene expression processes to ensure precise and efficient gene functionality in complex organisms.

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In early 2022, the confirmed presence of African swine fever (ASF) circulating in wild boars in mainland Italy and subsequently found in domestic pigs led to several changes regarding the export of pork and pork products to countries outside the European Union (non-EU). The sector suffered the complete and immediate closure of the markets of some countries, often without the measure being communicated in the forms stipulated by international agreements. Indeed, compliance with the current EU regulations does not guarantee the possibility of exporting to non-EU countries. Knowledge of the animal health status requirements of the country (Italy in this case) is essential for food business operators (FBOs) wishing to enter markets outside the EU according to the 'Agreement on the Application of Sanitary and Phytosanitary Measures'. In cases where a sanitary protocol and a model of an official certificate with the importing country exist, the market is officially accessible according to the agreed sanitary requirements. Where no agreement exists, requirements are detailed in the 'import permit' issued to individual FBOs or may be known by directly accessing national regulations through the client/importer. Therefore, the purpose of this work is to briefly outline the conditions imposed by the main non-EU countries for pork products, especially in light of the new epidemiological situation created by the spread of the ASF into a country previously free of the disease.

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Mutations in SF3B1 are common in many types of cancer, which promotes cancer progression through aberrant RNA splicing. Recently, mRNA nuclear export has been reported to be defective in cells with SF3B1 K700E mutation. However, the mechanism remains unclear. Our study reveals that the K700E mutation in SF3B1 attenuates its interaction with THOC5, an essential component of mRNA nuclear export complex THO. Furthermore, SF3B1 mutation caused reduced binding of THOC5 with some mRNA and inhibited the nuclear export of these mRNA. Interestingly, THOC5 overexpression restores the nuclear export of these mRNA in cells with SF3B1 K700E mutation. Importantly, other types of cancer-associated SF3B1 mutations also inhibited mRNA nuclear export similarly, suggesting that it is common for cancer-associated SF3B1 mutation to inhibit mRNA nuclear export. Our research highlights the critical role of the THOC5-SF3B1 interaction in the regulation of mRNA nuclear export and provides valuable insights into the impact of SF3B1 mutations on mRNA nuclear export.

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BACKGROUND: DEAD-box RNA helicase 19 A (DDX19A) is overexpressed in cervical squamous cell carcinoma. However, its role in gastric cancer remains unclear. The present study aimed to explore the role and underlying mechanism of DDX19A in the development of gastric cancer. METHODS: The expression of DDX19A in gastric cancer and paracancerous tissues was evaluated through quantitative polymerase chain reaction, western blotting, and immunohistochemical staining. The biological functions of DDX19A in gastric cancer were determined using CCK8, plate colony-forming, and Transwell migration assays. The specific mechanism of DDX19A in gastric cancer cells was studied using western blotting, RNA-binding protein immunoprecipitation, mRNA half-life detection, and nuclear and cytoplasmic RNA isolation. RESULTS: DDX19A was highly expressed in gastric cancer and positively associated with malignant clinicopathological features and poor prognosis. Additionally, DDX19A promoted gastric cancer cell proliferation, migration, and epithelial-mesenchymal transition phenotypes. Mechanistically, DDX19A activated the PI3K/AKT pathway by upregulating phosphatidylinositol-3-kinase (PIK3CA) expression. Furthermore, DDX19A interacted with PIK3CA mRNA, stabilized it, and facilitated its export from the nucleus. CONCLUSIONS: Our study reveals a novel mechanism whereby DDX19A promotes the proliferation and migration of gastric cancer cells by enhancing the stability and nuclear export of PIK3CA mRNA, thereby activating the PI3K/AKT pathway.

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BACKGROUND: The role of selinexor, a targeted inhibitor of exportin 1 (XPO1), in the treatment of cholangiocarcinoma is not yet fully understood. This study conducted comprehensive in vitro and in vivo investigations to elucidate the effects of selinexor on cholangiocarcinoma, with a focus on its mechanistic relationship with the cellular localization of Paternally Expressed Gene 3 (PEG3). METHODS: A patient-derived xenograft (PDX) model was established using samples from a cholangiocarcinoma patient in immunodeficient mice to assess the in vivo effects of selinexor. Additionally, cholangiocarcinoma cell lines HuCC-T1 and BRE were cultured to evaluate selinexor's impact on cell proliferation, invasion, migration, cell cycle, and apoptosis. HuCC-T1 cells were also implanted in immunodeficient mice for further investigation. Immunofluorescence and Western blotting were employed to observe the expression and localization of the PEG3 protein. RESULTS: The results demonstrated that selinexor significantly inhibited tumor growth in the cholangiocarcinoma PDX model and promoted the accumulation of PEG3 protein within the nuclei of tumor cells. In vitro experiments showed that selinexor effectively suppressed cholangiocarcinoma cell proliferation, invasion, and migration, while also impeding the cell cycle and inducing apoptosis. Notably, selinexor markedly facilitated the nuclear accumulation of PEG3 protein in cholangiocarcinoma cells. However, when PEG3 expression was knocked down, the effects of selinexor on cholangiocarcinoma were significantly reversed. CONCLUSION: These findings suggest that selinexor inhibits the progression of cholangiocarcinoma by targeting XPO1 and promoting the nuclear accumulation of PEG3 protein, thereby hindering the cell cycle and inducing apoptosis.

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SUN5, a testis-specific gene, is associated with acephalic spermatozoa syndrome (ASS). Here, we demonstrate that Sun5 is involved in mRNA export. In Sun5-knockout mice ( Sun5 -/-), poly(A) + RNA accumulates in the nuclei of germ cells, leading to reduced sperm counts, decreased sperm motility and disrupted sperm head-to-tail junctions. Additionally, in the GC-2 germ cell line with RNA interference of Sun5, heterogeneous nuclear ribonucleoproteins (hnRNPs) and poly (A) + RNA (mainly mRNA) are retained in the nucleus. Further mechanistic studies reveal that Sun5 interacts with Nxf1 (nuclear RNA export factor 1) and nucleoporin 93 (Nup93). Interference with Nup93 inhibits mRNA export. Treatment with leptomycin B to block the CRM1 pathway indicates that Sun5 regulates mRNA export through an Nxf1-dependent pathway. In Sun5 -/- mice, the binding of Nxf1 and Nup93 decreases due to loss of Sun5 function, and the process of submitting Nxf1-binding mRNPs to Nup93 is inhibited, resulting in abnormal spermatogenesis. Together, these data may elucidate a novel pathway for mRNA export in male germ cells.

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The TREX-2 complex of eukaryotes is responsible for the export of a wide range of mRNAs from the nucleus to the cytoplasm. Previously, we showed that a subunit of the D. melanogaster TREX-2 complex, the PCID2 protein, has a domain that specifically interacts with RNA. However, it remains unknown whether other components of the complex are involved in interaction with and recognition of the target mRNA. In the present study, we determined the role of Xmas-2, the core structural subunit of the complex, in the specific recognition of ras2 mRNA fragments. In this work, we showed that Xmas-2 interacts with ras2 mRNA independently of other subunits of the complex. We showed that RNA-binding domains are located in both the N-terminal domain and the C-terminal domain of Xmas-2. However, the interaction of the protein with ras2 mRNA fragments is independent of RNA sequence and structure and is nonspecific. Thus, the Xmas-2 subunit is not involved in the recognition of specific RNA sequences by the complex.

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MITF, a basic Helix-Loop-Helix Zipper (bHLHZip) transcription factor, plays vital roles in melanocyte development and functions as an oncogene. We perform a genetic screen for suppressors of the Mitf-associated pigmentation phenotype in mice and identify an intragenic Mitf mutation that terminates MITF at the K316 SUMOylation site, leading to loss of the C-end intrinsically disordered region (IDR). The resulting protein is more nuclear but less stable than wild-type MITF and retains DNA-binding ability. As a dimer, it can translocate wild-type and mutant MITF partners into the nucleus, improving its own stability thus ensuring nuclear MITF supply. smFRET analysis shows interactions between K316 SUMOylation and S409 phosphorylation sites across monomers; these interactions largely explain the observed effects. The recurrent melanoma-associated E318K mutation in MITF, which affects K316 SUMOylation, also alters protein regulation in concert with S409. This suggests that residues K316 and S409 of MITF are impacted by SUMOylation and phosphorylation, respectively, mediating effects on nuclear localization and stability through conformational changes. Our work provides a novel mechanism of genetic suppression, and an example of how apparently deleterious mutations lead to normal phenotypes.

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Thanks to its excellent climate and varied agroecological zones, Nepal has been a significant player in the global rose market. The geographical variety of the nation makes it possible to grow roses all year long, making it a desirable location for rose export and cultivation. The production and export of roses have significantly increased in recent years. The rose trade has increased in Nepal for several reasons. Investment in the industry has been stimulated by government measures to support floriculture and offer incentives to rose farmers. Additionally, the effective distribution of roses to domestic and foreign markets has been made possible by better transportation infrastructure. The growth of the global market has greatly aided the development of Nepal's rose industry. The growth of rose cultivation in Nepal has significantly impacted the economy and employment. It is a good source of revenue through internal sales, export, and other activities that provide value addition. The sector creates direct farm jobs while local communities benefit from indirect employment in supporting industries. In addition, there is increased job opportunities due to seasonal spikes in demand. Rose exports have expanded due to a rise in demand for Nepali roses, particularly in European markets and nearby nations like India. The favorable trade agreements Nepal has with several nations have helped to increase its exports even more. But issues still exist in the rose trade sector. Since maintaining consistent quality is necessary to compete in the international market, quality control and standardization continue to be areas of concern. The rose business in Nepal is also vulnerable to changes in global demand and competition from other nations that grow roses. Further expansion of the industry will help it overcome problems like limited technology and training hence leading to its fast development; this calls for government support as well as market expansion. In conclusion, the rose trade environment in Nepal is a fluid and changing one. Due to favorable circumstances, government assistance, and global demand, the sector has seen significant expansion. Continuous efforts in quality control, market diversification, and innovation are necessary to maintain and grow this sector. The rose trade in Nepal has the potential to significantly boost the nation's agricultural exports while promoting economic growth in rural areas.

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The PCID2 protein is a component of the eukaryotic TREX-2 complex, which is responsible for mRNA export from the nucleus into the cytoplasm. We have previously shown that Drosophila melanogaster PCID2 is involved in specific mRNA recognition and identified the key amino acids responsible for its interaction with the ras2 RNA. In this work, point mutations of the amino acids were shown to disrupt the PCID2 interaction with cell RNAs and to distort the export of polyA-containing mRNAs from the nucleus into the cytoplasm in Drosophila cells.

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Formation of the Dorsal nuclear-cytoplasmic gradient is important for the proper establishment of gene expression patterns along the dorsal-ventral (DV) axis during embryogenesis in Drosophila melanogaster. Correct patterning of the DV axis leads to formation of the presumptive mesoderm, neurogenic ectoderm, dorsal ectoderm, and amnioserosa, which are tissues necessary for embryo viability. While Toll signaling is necessary for Dorsal gradient formation, a gradient still forms in the absence of Toll, suggesting there are additional mechanisms required to achieve correct nuclear Dorsal levels. Potential mechanisms include post-translational modification, shuttling, and nuclear spacing. Post-translational modification could affect import and export rates either directly through modification of a nuclear localization sequence or nuclear export sequence, or indirectly by affecting interactions with binding partners that alter import and export rates. Shuttling, which refers to the facilitated diffusion of Dorsal through its interaction with its cytoplasmic inhibitor Cactus, could regulate nuclear levels by delivering more Dorsal ventrally. Finally, nuclear spacing could result in higher nuclear levels by leaving fewer nuclei in the ventral domain to uptake Dorsal. This review details how each of these mechanisms may help establish Dorsal nuclear levels in the early fly embryo, which serves as a paradigm for understanding how the dynamics of graded inputs can influence patterning and target gene expression. Furthermore, careful analysis of nuclear Dorsal levels is likely to provide general insights as recent studies have suggested that the regulation of nuclear import affects the timing of gene expression at the maternal-to-zygotic transition.

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Pollution fluxes from rivers into the sea are currently the main source of pollutants in nearshore areas. Based on the source-sink process of the basin-estuary-coastal waters system, the pollution fluxes into the sea and their spatiotemporal heterogeneity were estimated. A deep learning-based model was established to simplify the estimation of pollution fluxes into the sea, with socio-economic drivers and meteorological data as input variables. A method for estimating the contribution rate of pollution fluxes from different spatial gradient was proposed. In this study, we found that (1) the pollution fluxes into the sea of total nitrogen (TN) and total phosphorus (TP) from the Bohai Sea Rim Basin (BSRB) in 1980, 1990, 2000, 2010, and 2020 were 25.38 × 104, 26.12 × 104, 27.27 × 104, 29.82 × 104, 25.31 × 104 and 1.32 × 104, 2.14 × 104, 2.09 × 104, 1.87 × 104, 1.68 × 104 tons, respectively. (2) The proportion of rural life and livestock to the TN was the highest, accounting for 39.18 % and 21.19 %, respectively. The proportion of livestock to the TP was the highest, accounting for 39.20 %, followed by rural life, accounting for 24.72 %. The results indicated that the pollution fluxes in the BSRB were related to human economic activities and relevant environmental protection measures. (3) The deep learning-based model established to estimate runoff pollution fluxes into the sea had the accuracy of over 90 %. (4) As for contribution rate, in terms of the elevation, the range of 0-100 m had the highest proportion, accounting for 39.65 %. The range of 50-100 km from the coastline had the highest proportion, accounting for 18.11 %. In terms of the district, coastal area has the highest proportion, accounting for 38.00 %. This study revealed the changing trends and driving mechanisms of pollution fluxes into the sea over the past 40 years and established a simplified deep learning-based model for estimating pollution fluxes into the sea. Then, we identified regions with high pollution contribution rate. The results can provide scientific references for the adaptive management of the nearshore areas based on the ecosystem.

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Exportin5 (Exp5) is the major miRNA nuclear export factor and recognizes structural features of pre-miRNA hairpins, while it also exports other minihelix-containing RNAs. In Drosophila, Exp5 is suggested to play a major role in tRNA export because the gene encoding the canonical tRNA export factor Exportin-t is missing in its genome. To understand molecular functions of fly Exp5, we studied the Exp5/RNA interactome in the cell line S2R + using the crosslinking and immunoprecipitation (CLIP) technology. The CLIP experiment captured known substrates such as tRNAs and miRNAs and detected candidates of novel Exp5 substrates including various mRNAs and long non-coding RNAs (lncRNAs). Some mRNAs and lncRNAs enriched PAR-CLIP tags compared to their expression levels, suggesting selective binding of Exp5 to them. Intronless mRNAs tended to enrich PAR-CLIP tags; therefore, we proposed that Exp5 might play a role in the export of specific classes of mRNAs/lncRNAs. This result suggested that Drosophila Exp5 might have a wider variety of substrates than initially thought. Surprisingly, Exp5 CLIP reads often contained sequences corresponding to the flanking 5'-leaders and 3'-trailers of tRNAs, which were thought to be removed prior to nuclear export. In fact, we found pre-tRNAs before end-processing were present in the cytoplasm, supporting the idea that tRNA end-processing is a cytoplasmic event. In summary, our results provide a genome-wide list of Exp5 substrate candidates and suggest that flies may lack a mechanism to distinguish pre-tRNAs with or without the flanking sequences.