Emerging evidence suggests that intron-detaining transcripts (IDTs) are a nucleus-detained and polyadenylated mRNA pool for cell to quickly and effectively respond to environmental stimuli and stress. However, the underlying mechanisms of detained intron (DI) splicing are still largely unknown. Here, we suggest that post-transcriptional DI splicing is paused at the Bact state, an active spliceosome but not catalytically primed, which depends on Smad Nuclear Interacting Protein 1 (SNIP1) and RNPS1 (a serine-rich RNA binding protein) interaction. RNPS1 and Bact components preferentially dock at DIs and the RNPS1 docking is sufficient to trigger spliceosome pausing. Haploinsufficiency of Snip1 attenuates neurodegeneration and globally rescues IDT accumulation caused by a previously reported mutant U2 snRNA, a basal spliceosomal component. Snip1 conditional knockout in the cerebellum decreases DI splicing efficiency and causes neurodegeneration. Therefore, we suggest that SNIP1 and RNPS1 form a molecular brake to promote spliceosome pausing, and that its misregulation contributes to neurodegeneration.
Spliceosomes/metabolism* ; Introns/genetics* ; RNA Splicing ; RNA, Messenger/genetics* ; Cell Nucleus/metabolism*

Rice stripe virus (RSV) transmitted by the small brown planthopper causes severe rice yield losses in Asian countries. Although viral nuclear entry promotes viral replication in host cells, whether this phenomenon occurs in vector cells remains unknown. Therefore, in this study, we systematically evaluated the presence and roles of RSV in the nuclei of vector insect cells. We observed that the nucleocapsid protein (NP) and viral genomic RNAs were partially transported into vector cell nuclei by utilizing the importin α nuclear transport system. When blocking NP nuclear localization, cytoplasmic RSV accumulation significantly increased. In the vector cell nuclei, NP bound the transcription factor YY1 and affected its positive regulation to FAIM. Subsequently, decreased FAIM expression triggered an antiviral caspase-dependent apoptotic reaction. Our results reveal that viral nuclear entry induces completely different immune effects in vector and host cells, providing new insights into the balance between viral load and the immunity pressure in vector insects.
Animals ; Cell Nucleus ; Hemiptera/metabolism* ; Insect Vectors/genetics* ; Insecta ; Nucleocapsid Proteins/metabolism* ; Oryza ; Plant Diseases ; Tenuivirus/metabolism* ; Virus Replication

BACKGROUND: The Nuclear Dbf2-related (NDR1) kinase is a member of the NDR/LATS family, which was a supplementary of Hippo pathway. However, whether NDR1 could inhibit glioblastoma (GBM) growth by phosphorylating Yes-associated protein (YAP) remains unknown. Meanwhile, the role of NDR1 in GBM was not clear. This study aimed to investigate the role of NDR1-YAP pathway in GBM. METHODS: Bioinformation analysis and immunohistochemistry (IHC) were performed to identify the expression of NDR1 in GBM. The effect of NDR1 on cell proliferation and cell cycle was analyzed utilizing CCK-8, clone formation, immunofluorescence and flow cytometry, respectively. In addition, the xenograft tumor model was established as well. Protein interaction was examined by Co-immunoprecipitation and immunofluorescence to observe co-localization. RESULTS: Bioinformation analysis and IHC of our patients' tumor tissues showed that expression of NDR1 in tumor tissue was relatively lower than that in normal tissues and was positively related to a lower survival rate. NDR1 could markedly reduce the proliferation and colony formation of U87 and U251. Furthermore, the results of flow cytometry showed that NDR1 led to cell cycle arrest at the G1 phase. Tumor growth was also inhibited in xenograft nude mouse models in NDR1-overexpression group. Western blotting and immunofluorescence showed that NDR1 could integrate with and phosphorylate YAP at S127 site. Meanwhile, NDR1 could mediate apoptosis process. CONCLUSION In summary, our findings point out that NDR1 functions as a tumor suppressor in GBM. NDR1 is identified as a novel regulator of YAP, which gives us an in-depth comprehension of the Hippo signaling pathway.
Animals ; Cell Nucleus/metabolism* ; Cell Proliferation ; Glioblastoma ; Humans ; Mice ; Phosphorylation ; Protein-Serine-Threonine Kinases/metabolism* ; Signal Transduction

Nuclear bodies are membrane-free nuclear substructures that are localized in the mammalian nuclear matrix region. They are multiprotein complexes that recruit other proteins to participate in various cellular activities, such as transcription, RNA splicing, epigenetic regulation, tumorigenesis and antiviral defense. It is of great significance to clarify the functions and regulatory mechanisms of nuclear bodies to probe related diseases and virus-host interactions. This review takes several nuclear bodies associated proteins as examples, summarizes the formation process, structure and functions of nuclear bodies, and focuses on their important roles in antiviral infection. It is expected to provide new insight into host antiviral mechanisms.
Animals ; Cell Nucleus ; Epigenesis, Genetic ; Intranuclear Inclusion Bodies/metabolism* ; Nuclear Proteins/metabolism*

Proteins are the physical basis of life and perform all kinds of life activities. Proteins have different orientations and function in different tissues. The same protein, located in different subcellular regions, can perform different and even opposite functions. Both functional and structural proteins are capable of undergoing re-localization which can directly or indirectly participate in signal transduction. Due to abnormal transduction of signals during carcinogenesis, the proteins originally expressed in the cytoplasm are translocated into the nucleus and lead to functional changes in the tumor tissue. The changes of protein localization are affected by many factors, including the interaction between proteins, expression level of proteins and the cleaved intracellular domain of transmembrane protein.
Carcinogenesis ; pathology ; Cell Line, Tumor ; Cell Nucleus ; metabolism ; Cytoplasm ; metabolism ; Gene Expression Regulation, Neoplastic ; Humans ; Membrane Proteins ; metabolism ; Protein Domains ; Protein Transport ; physiology ; Signal Transduction

OBJECTIVE: To investigate the expression of EGR1 gene and the localization of EGR1 protein in bovine skeletal muscle-derived satellite cells (MDSCs), as well as to investigate the mechanism that EGR1 protein enters the nucleus. METHODS: Bovine MDSCs were cultured in differentiation medium for 1 day, 3 days and 5 days, respectively, and each group was triplicate. The expression of EGR1 gene and the localization of EGR1 protein were studied at different differentiation period in MDSCs by qRT-PC and Western blot. Moreover, the changes on the expression of endogenous EGR1 gene and EGR1 proteins were explored by CRISPRi, site-directed mutagenesis and laser confocal method. RESULTS: The results from the qRT-PCR and Western blot showed that the expressions of EGR1 gene on transcription level and translation level were significantly higher in differentiated cells than those in undifferentiated cells. The highest expression was found on the third day after the differentiation, and then began to decline. Immunofluorescence assays showed that EGR1 proteins were preferentially expressed in differentiated MDSCs, and increased along with the increase of number of myotubes. Confocal observation revealed that some EGR1 proteins were transferred into the nucleus in the differentiation of cells, however, the EGR1 proteins would not be detected in the differentiated MDSCs nuclei if a site directed mutagenesis (serine) on EGR1 protein occurred. CONCLUSION During the differentiation of bovine skeletal muscle satellite cells, the transcriptional level of EGR1 gene is increased, and some EGR1 proteins are transferred into the nucleus. The serine phosphorylation at position 533 of the C terminal of EGR1 protein is necessary for the nucleus transfer.
Animals ; Cattle ; Cell Differentiation ; Cell Nucleus ; Cells, Cultured ; Early Growth Response Protein 1 ; genetics ; metabolism ; Muscle Fibers, Skeletal ; Satellite Cells, Skeletal Muscle ; metabolism

OBJECTIVE: To investigate the anti-neuroinflammation effect of extract of Fructus Schisandrae chinensis (EFSC) on lipopolysaccharide (LPS)-induced BV-2 cells and the possible involved mechanisms. METHODS: Primary cortical neurons were isolated from embryonic (E17-18) cortices of Institute of Cancer Research (ICR) mouse fetuses. Primary microglia and astroglia were isolated from the frontal cortices of newborn ICR mouse. Different cells were cultured in specific culture medium. Cells were divided into 5 groups: control group, LPS group (treated with 1 μg/mL LPS only) and EFSC groups (treated with 1 μg/mL LPS and 100, 200 or 400 mg/mL EFSC, respectively). The effect of EFSC on cells viability was tested by methylthiazolyldiphenyltetrazolium bromide (MTT) colorimetric assay. EFSC-mediated inhibition of LPS-induced production of pro-inflammatory mediators, such as nitrite oxide (NO) and interleukin-6 (IL-6) were quantified and neuron-protection effect against microglia-mediated inflammation injury was tested by hoechst 33258 apoptosis assay and crystal violet staining assay. The expression of pro-inflammatory marker proteins was evaluated by Western blot analysis or immunofluorescence. RESULTS: EFSC (200 and 400 mg/mL) reduced NO, IL-6, inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) expression in LPS-induced BV-2 cells (P<0.01 or P<0.05). EFSC (200 and 400 mg/mL) reduced the expression of NO in LPS-induced primary microglia and astroglia (P<0.01). In addition, EFSC alleviated cell apoptosis and inflammation injury in neurons exposed to microglia-conditioned medium (P<0.01). The mechanistic studies indicated EFSC could suppress nuclear factor (NF)-?B phosphorylation and its nuclear translocation (P<0.01). The anti-inflammatory effect of EFSC occurred through suppressed activation of mitogen-activated protein kinase (MAPK) pathway (P<0.01 or P<0.05). CONCLUSION EFSC acted as an anti-inflammatory agent in LPS-induced glia cells. These effects might be realized through blocking of NF-κB activity and inhibition of MAPK signaling pathways.
Animals ; Astrocytes ; drug effects ; metabolism ; pathology ; Cell Line ; Cell Nucleus ; drug effects ; metabolism ; Chromatography, High Pressure Liquid ; Down-Regulation ; drug effects ; Inflammation ; pathology ; Inflammation Mediators ; metabolism ; Lipopolysaccharides ; MAP Kinase Signaling System ; drug effects ; Mice, Inbred ICR ; Microglia ; drug effects ; metabolism ; pathology ; NF-kappa B ; metabolism ; Nervous System ; pathology ; Neurons ; drug effects ; metabolism ; pathology ; Neuroprotective Agents ; pharmacology ; Plant Extracts ; pharmacology ; Schisandra ; chemistry ; Spectrometry, Mass, Electrospray Ionization

OBJECTIVETo investigate the effect of total flavone of haw leaves (TFHL) on the expression of nuclear factor erythroid-2 related factor (Nrf2) and other related factors in nonalcoholic steatohepatitis (NASH) rats induced by high-fat diet and then to further discuss the mechanism of TFHL's prevention against NASH.

METHODSHigh-fat diet was fed to 40 rats to establish the NASH model. Then model rats were intragastrically administrated with 40, 80, 160 mg/(kg•day) TFHL, respectively. The pathological changes of liver tissues in NASH rats were detected by oil red O and hematoxylin-eosin (HE) stainings. The expression of Nrf2 in rat liver was examined through immunohistochemistry. The level of 8-iso-prostaglandin F2α in serum was detected through enzyme linked immunosorbent assay (ELISA). The mRNA and protein levels of Nrf2 and other related factors in liver tissue were measured by real-time reverse transcriptionpolymerase chain reaction and western blot.

RESULTSLipid deposition, hepatic steatosis, focal necrosis in lobular inflammation and ballooning degeneration were emerged in livers of NASH rats. The 8-iso-prostaglandin F2α in the serum of NASH rats increased significantly compared with the control group (P<0.05). The mRNA of Nrf2, hemeoxyenase1 (HO-1) and the mRNA and protein levels of quinine oxidoreductase (NQO1) in NASH rats liver tissue showed a striking increase, while the mRNA levels of Keap1, r-glutamylcysteine synthethase (rGCS) and glutathione S-transferase (GST) were significantly decreased compared with the control group (P<0.05). After TFHL treatment, 8-iso-prostaglandin F2α level in serum significantly decreased, and Nrf2 mRNA and protein levels in hepatocytes nucleus enhanced compared with the model group (P<0.05 or 0.01). Meanwhile the Keap1 mRNA, the mRNA and protein levels of HO-1, NQO1 antibody, rGCS antibody, GST increased after TFHL treatment (P<0.05 or 0.01).

CONCLUSIONSNrf2 and other related factors were involved in development of NASH, and they also served as an important part in its occurrence. By regulating expression of Nrf2 and other related factors, TFHL may play a role in antioxidative stress and prevention of NASH.

Animals ; Cell Nucleus ; drug effects ; metabolism ; Crataegus ; chemistry ; Dinoprost ; metabolism ; Flavones ; pharmacology ; therapeutic use ; Lipids ; chemistry ; Liver ; drug effects ; metabolism ; pathology ; NF-E2-Related Factor 2 ; genetics ; metabolism ; Non-alcoholic Fatty Liver Disease ; drug therapy ; genetics ; pathology ; Phytotherapy ; Plant Leaves ; chemistry ; RNA, Messenger ; genetics ; metabolism ; Rats, Sprague-Dawley

Fibroblast-like synoviocytes (FLS) play a pivotal role in Rheumatoid arthritis (RA) pathogenesis through aggressive migration and invasion. Madecassoside (Madec), a triterpenoid saponin present in Centella asiatica herbs, has a potent anti-inflammatory effect. In the present study, Madec exerted an obvious therapeutic effect in reversing the histological lesions in adjuvant-induced arthritis (AIA) rats. To recognize the anti-rheumatoid potentials of Madec, we further investigated whether Madec interfered with FLS invasion and metalloproteinase (MMP) expression. In cultures of primary FLS isolated from the AIA rats, Madec (10 and 30 μmol·L) was proven to considerably inhibit migration and invasion of FLS induced by interleukin 1β (IL-1β), but exhibiting no obvious effect on cell proliferation. Madec repressed IL-1β-triggered FLS invasion by prohibiting the expression of MMP-13. Additionally, Madec suppressed MMP-13 transcription via inhibiting the MMP-13 promoter-binding activity of NF-κB. Our results further showed that Madec down-regulated the translocation and phosphorylation of NF-κB as demonstrated by Western blotting and immunofluorescence assays. In conclusion, our results suggest that Madec exerts anti-RA activity via inhibiting the NF-κB/MMP-13 pathway.
Animals ; Antirheumatic Agents ; chemistry ; pharmacology ; therapeutic use ; Arthritis, Experimental ; chemically induced ; drug therapy ; pathology ; Cell Movement ; drug effects ; Cell Nucleus ; metabolism ; Cells, Cultured ; Gene Expression Regulation, Enzymologic ; drug effects ; Interleukin-1beta ; pharmacology ; Matrix Metalloproteinase 13 ; genetics ; NF-kappa B ; genetics ; metabolism ; Phosphorylation ; drug effects ; Protein Transport ; drug effects ; Rats ; Signal Transduction ; drug effects ; Synoviocytes ; drug effects ; metabolism ; Transcriptional Activation ; drug effects ; Triterpenes ; chemistry ; pharmacology ; therapeutic use

Annexin A2, a multifunctional tumor associated protein, promotes nuclear factor-kappa B (NF-κB) activation by interacting with NF-κB p50 subunit and facilitating its nuclear translocation. Here we demonstrated that two ginsenosides Rg5 (G-Rg5) and Rk1 (G-Rk1), with similar structure, directly bound to Annexin A2 by molecular docking and cellular thermal shift assay. Both Rg5 and Rk1 inhibited the interaction between Annexin A2 and NF-κB p50 subunit, their translocation to nuclear and NF-κB activation. Inhibition of NF-κB by these two ginsenosides decreased the expression of inhibitor of apoptosis proteins (IAPs), leading to caspase activation and apoptosis. Over expression of K302A Annexin A2, a mutant version of Annexin A2, which fails to interact with G-Rg5 and G-Rk1, effectively reduced the NF-κB inhibitory effect and apoptosis induced by G-Rg5 and G-Rk1. In addition, the knockdown of Annexin A2 largely enhanced NF-κB activation and apoptosis induced by the two molecules, indicating that the effects of G-Rg5 and G-Rk1 on NF-κB were mainly mediated by Annexin A2. Taken together, this study for the first time demonstrated that G-Rg5 and G-Rk1 inhibit tumor cell growth by targeting Annexin A2 and NF-κB pathway, and G-Rg5 and G-Rk1 might be promising natural compounds for targeted cancer therapy.
Active Transport, Cell Nucleus ; drug effects ; Annexin A2 ; chemistry ; deficiency ; genetics ; metabolism ; Antineoplastic Agents ; chemistry ; metabolism ; pharmacology ; Apoptosis ; drug effects ; Biological Products ; chemistry ; metabolism ; pharmacology ; Cell Nucleus ; drug effects ; metabolism ; Down-Regulation ; drug effects ; Drug Discovery ; Gene Knockdown Techniques ; Ginsenosides ; chemistry ; Hep G2 Cells ; Humans ; Molecular Docking Simulation ; Molecular Targeted Therapy ; NF-kappa B p50 Subunit ; metabolism ; Protein Conformation