OBJECTIVE: To explore the expression and clinical significance of XPO1 in newly diagnosed adult diffuse large B-cell lymphoma (DLBCL), and further investigate its functional mechanism. METHODS: Immunohistochemical testing was conducted for XPO1 expression in 93 cases of DLBCL and 30 cases of reactive lymphoid hyperplasia. A risk model was construed to find survival related genes in DLBCL patients. Cell proliferation, apoptosis, and cell cycle assays were performed to explore the effect of XPO1 inhibitor (KPT-8602) and XPO1 knockdown. Differential expression gene (DEG) was examined based on the transcriptomes. RESULTS The expression of XPO1 in DLBCL patients was higher than that of the controls. Compared with XPO1 low-expression group, XPO1 high-expression group had a worse prognosis. The constructed risk model indicated that XPO1 and 14 genes in nucleocytoplasmic transport pathway (NTP) might be potential prediction marker of adverse outcome in DLBCL. Moreover, KPT-8602 as well as the XPO1 knockdown could inhibit cell proliferation, promote apoptosis, and induce cell cycle arrest in two DLBCL cell lines, Farage and SU-DHL-4. Based on the gene expression profiling in the datasets of DLBCL, patients were classified into XPO1 high and XPO1 low expression groups, and the MYBL1 was identified as the down-stream effector of XPO1. Inhibiting the function of XPO1 or reducing its expression can significantly decrease the expression of MYBL1 Conclusion: XPO1 is highly expressed in DLBCL, which is associated with poor prognosis. The oncogenic roles of the new XPO1/MYBL1 signaling are identified in DLBCL and XPO1 inhibitor may be a potential option for newly-diagnosed DLBCL patients.
Humans ; Lymphoma, Large B-Cell, Diffuse/pathology* ; Exportin 1 Protein ; Karyopherins/metabolism* ; Receptors, Cytoplasmic and Nuclear/metabolism* ; Cell Proliferation ; Apoptosis ; Prognosis ; Cell Line, Tumor ; Clinical Relevance

Bombyx mori nucleopolyhedrovirus (BmNPV) is extremely harmful to the silk industry. The polyhedrin, which encodes the polyhedrin (Polh), can be expressed at ultra-high levels and form occlusion bodies in the nucleus, embedding the progeny virus within it. However, the detailed mechanism by which polyhedrin is transported into the host cell nucleus remains unknown. Clarifying the nuclear import mechanisms of viral proteins can help us develop better prevention and treatment measures against baculoviruses. This study employed molecular cloning, co-immunoprecipitation, and immunofluorescence to analyze in detail the expression pattern of the highly expressed polyhedrin in the very late stage of the virus, and further revealed that the host protein importin α participates in the nuclear import of polyhedrin through protein interactions. This study provides a reference for further elucidating the nuclear import mechanisms of the baculovirus proteins including polyhedrin that can enter the nucleus.
Nucleopolyhedroviruses/metabolism* ; Active Transport, Cell Nucleus ; Animals ; Bombyx/virology* ; alpha Karyopherins/metabolism* ; Cell Nucleus/metabolism* ; Viral Structural Proteins/metabolism* ; Occlusion Body Matrix Proteins

OBJECTIVE: To explore the genetic basis for a neonate featuring developmental delay. METHODS: Clinical examination and laboratory tests were carried out for the patient. Peripheral venous blood samples of the proband and his parents were extracted and subjected to target capture next generation sequencing. Candidate variant was verified by Sanger sequencing. RESULTS: The patient, a four-month-old male, has presented with developmental delay and weakness of limbs. Genetic testing revealed that he had harbored a novel c.1432C>T variant of the TNPO3 gene, which was inherited from his mother. The nonsense variant has resulted in premature termination of protein translation and was predicted to be pathogenic by bioinformatics analysis. CONCLUSION The heterozygous c.1432C>T variant of the TNPO3 gene probably underlay the limb-girdle muscular dystrophies form 1F in this patient. Above finding has enriched the variation spectrum of the TNPO3 gene.
Genetic Testing ; Heterozygote ; High-Throughput Nucleotide Sequencing ; Humans ; Infant ; Male ; Muscular Dystrophies, Limb-Girdle/genetics* ; Mutation ; Phenotype ; beta Karyopherins/genetics*

Hypoxia-inducible factor 1 (HIF1) is a master transcription factor that induces the transcription of genes involved in the metabolism and behavior of stem cells. HIF1-mediated adaptation to hypoxia is required to maintain the pluripotency and survival of stem cells under hypoxic conditions. HIF1 activity is well known to be tightly controlled by the alpha subunit of HIF1 (HIF1α). Understanding the regulatory mechanisms that control HIF1 activity in stem cells will provide novel insights into stem cell biology under hypoxia. Recent research has unraveled the mechanistic details of HIF1α regulating processes, suggesting new strategies for regulating stem cells. This review summarizes recent experimental studies on the role of several regulatory factors (including calcium, 2-oxoglutarate-dependent dioxygenase, microtubule network, importin, and coactivators) in regulating HIF1α activity in stem cells.
Anoxia ; Biology ; Calcium ; Hypoxia-Inducible Factor 1 ; Karyopherins ; Metabolism ; Microtubules ; Stem Cells ; Transcription Factors

MicroRNAs (miRNAs) are conserved small non-coding RNAs that play an important role in the regulation of gene expression and participate in a variety of biological processes. The biogenesis of miRNAs is tightly controlled at multiple steps, such as transcription of miRNA genes, processing by Drosha and Dicer, and transportation of precursor miRNAs (pre-miRNAs) from the nucleus to the cytoplasm by exportin-5 (XPO5). Given the critical role of nuclear export of pre-miRNAs in miRNA biogenesis, any alterations of XPO5, resulting from either genetic mutation, epigenetic change, abnormal expression level or posttranslational modification, could affect miRNA expression and thus have profound effects on tumorigenesis. Importantly, XPO5 phosphorylation by ERK kinase and its cis/trans isomerization by the prolyl isomerase Pin1 impair XPO5's nucleo-to-cytoplasmic transport ability of pre-miRNAs, leading to downregulation of mature miRNAs in hepatocellular carcinoma. In this review, we focus on how XPO5 transports pre-miRNAs in the cells and summarize the dysregulation of XPO5 in human tumors.
Carcinoma, Hepatocellular ; genetics ; metabolism ; Cell Nucleus ; metabolism ; Cytoplasm ; metabolism ; Humans ; Karyopherins ; chemistry ; metabolism ; physiology ; Liver Neoplasms ; genetics ; metabolism ; MicroRNAs ; chemistry ; metabolism ; NIMA-Interacting Peptidylprolyl Isomerase ; Neoplasms ; genetics ; metabolism ; RNA Precursors ; chemistry ; metabolism ; RNA Transport

Aging-dependent cellular behaviors toward extrinsic stress are characterized by the confined localization of certain molecules to either nuclear or perinuclear regions. Although most growth factors can activate downstream signaling in aging cells, they do not in fact have any impact on the cells because the signals cannot reach their genetic targets in the nucleus. For the same reason, varying apoptotic stress factors cannot stimulate the apoptotic pathway in senescent cells. Thus, the operation of a functional nuclear barrier in an aging-dependent manner has been investigated. To elucidate the mechanism for this process, the housekeeping transcription factor Sp1 was identified as a general regulator of nucleocytoplasmic trafficking (NCT) genes, including various nucleoporins, importins, exportins and Ran GTPase cycle-related genes. Interestingly, the posttranslational modification of Sp1 is readily influenced by extrinsic stress, including oxidative and metabolic stress. The decrease in SP1 O-GlcNAcylation under oxidative stress or during replicative senescence makes it susceptible to proteosomal degradation, resulting in defective NCT functions and leading to nuclear barrier formation. The operation of the nuclear barrier in aging provides a fundamental mechanism for cellular protection against stress and promotes survival at the expense of growth via stress-sensitive transcriptional control.
Aging ; Cell Aging* ; GTP Phosphohydrolases ; Housekeeping ; Intercellular Signaling Peptides and Proteins ; Karyopherins ; Nuclear Pore Complex Proteins ; Oxidative Stress ; Protein Processing, Post-Translational ; Stress, Physiological ; Transcription Factors

Transportation between the cytoplasm and the nucleoplasm is critical for many physiological and pathophysiological processes including gene expression, signal transduction, and oncogenesis. So, the molecular mechanism for the transportation needs to be studied not only to understand cell physiological processes but also to develop new diagnostic and therapeutic targets. Recent progress in the research of the nuclear transportation (import and export) via nuclear pore complex and four important factors affecting nuclear transport (nucleoporins, Ran, karyopherins, and nuclear localization signals/nuclear export signals) will be discussed. Moreover, the clinical significance of nuclear transport and its application will be reviewed. This review will provide some critical insight for the molecular design of therapeutics which need to be targeted inside the nucleus.
Active Transport, Cell Nucleus* ; Carcinogenesis ; Cell Physiological Processes ; Cytoplasm ; Gene Expression ; Karyopherins ; Nuclear Localization Signals ; Nuclear Pore ; Nuclear Pore Complex Proteins ; Signal Transduction ; Transportation

High expression of Fightless I (FLII) is associated to multiple tumors. Based on our previous study that FLII might be involved in the nuclear export, we assessed the possible interaction of FLII with the nuclear envelop associating proteins Importin β and Nup88. We first constructed GST-FLII, GST-LRR recombinant plasmids and transformed them into the Rosetta strain to produce GST-FLII, GST-LRR fusion protein. After purification of these proteins, GST-pull down, as well as co-immunoprecipitation, were used to test the interaction of FLII with Importin β and Nup88. FLII interacted with Importin β and Nup88, and FLII LRR domain is responsible for these interactions. Thus, FLII may play a role in nuclear export through interaction with Importin β and Nup88.
Humans ; Microfilament Proteins ; metabolism ; Nuclear Pore Complex Proteins ; metabolism ; Receptors, Cytoplasmic and Nuclear ; metabolism ; Recombinant Fusion Proteins ; metabolism ; beta Karyopherins ; metabolism

Bel1, a transactivator of prototype foamy virus (PFV), plays pivotal roles in the replication of PFV. Previous studies have shown that Bel1 bears a nuclear localization signal (NLS), but its amino acid sequence remains unclear and the corresponding importins have not been identified. In this report, we inserted various fragments of Bel1 into an EGFP-GST fusion protein and investigated their subcellular localization by fluorescence microscopy. We found that the 215PRQKRPR221 fragment could direct nuclear localization, which accords with the consensus sequence K(K/R)X(K/R) of monopartite NLS. Point mutation experiments revealed that K218, R219, and R221 are essential for the nuclear localization of Bel1. The results of the GST-pulldown showed that the Bel1 fragment with residues 215-223, which bears the NLS, interacts with KPNA1, KPNA6, and KPNA7. This result suggests that KPNA1, KPNA6, and KPNA7 maybe involved in Bel1 nuclear translocation.
Cell Line ; Cell Nucleus ; genetics ; metabolism ; virology ; Humans ; Nuclear Localization Signals ; genetics ; metabolism ; Protein Binding ; Protein Transport ; Retroviridae Infections ; genetics ; metabolism ; virology ; Retroviridae Proteins ; chemistry ; genetics ; metabolism ; Spumavirus ; chemistry ; genetics ; physiology ; Trans-Activators ; chemistry ; genetics ; metabolism ; alpha Karyopherins ; genetics ; metabolism

OBJECTIVE: To clone 5' untranslated region of human IPO8 gene and determine its transcription activity. METHODS: We used 5' rapid amplification of cDNA ends (RACE) analysis to identify the IPO8 transcription start site (TSS), and amplified series truncated 5' UTR fragment containing transcription start site. The PCR productions were inserted into luciferase report vector pGL3- Basic. After confirmation by restriction enzyme digestion, the recombinant plasmids were cotransfected into Saos-2 cells with plasmid pRL-TK. The luciferase activities were measured by dual luciferase reporter system. RESULTS: The IPO8 gene transcription start site was established. The electrophoresis analysis of restriction enzyme digestion and DNA sequencing verified the fragments were successfully amplified and inserted into pGL3-Basic. After the recombinant plasmids transfected, the highexpressions of luciferase were detected in Saos-2 cells. CONCLUSION The recombinant vector containing IPO8 promoter is constructed successfully, which provides a foundation for determining expressional regulation of IPO8 in the further study.
Cloning, Molecular ; DNA, Complementary ; Genetic Vectors ; Humans ; Luciferases ; Plasmids ; Promoter Regions, Genetic ; Transfection ; beta Karyopherins ; genetics