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Objective To investigate the sub-cellular distribution correlation between activated LIMK1 (pLIMK1Thr508) and Aurora-A in mouse oocyte meiosis,and changes in Aurora-A location and spindle structure in condition of LIMK1 inhibition.Methods Immunofluorescence staining was employed to detect the sub-cellular localization of pLIMK1Thr508and its spatial-temporal correlation with spindle organizing regulator Aurora-A in mouse oocyte meiosis; BMS-3, the specific inhibitor to LIMK1 activity, was applied to analyze the effects of LIMK1 inhibition on Aurora-A distribution and spindle formation. Results At meiotic prophase,pLIMK1Thr508was weakly detected and concentrated in the germinal vesicle(GV) in oocytes,with no signal of Aurora-A across the cytoplasm and nuclear area;as meiotic assumption approaching,pLIMK1Thr508left nuclear,aggregating as a single dense dote in the vicinity of nuclear, and being co-localized with the emerging Aurora-A; After germinal vesicle broke down (GVBD), pLIMK1Thr508and Aurora-A remained overlapped and concentrated as multi foci around the condensed chromosomes;at metaphase Ⅰ(MⅠ) and metaphase Ⅱ(MⅡ), pLIMK1Thr508was co-localized with Aurora-A on spindle poles;During anaphase Ⅰ(AⅠ) to telophase Ⅰ(Tel Ⅰ) progression, pLIMK1Thr508was detached from spindle poles and mainly concentrated on the cleavage furrow,while Aurora-A loosely congressed on spindle. In ad-dition, LIMK1 inhibition with BMS- 3 destroyed Aurora-A polar location and spindle formation. Conclusions pLIMK1Thr508is a microtubule organizing center (MTOC)-associated protein, may participate in spindle assembly and maintenance through regulating Aurora-A in mouse oocytes during meiotic progression.
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Background Epithelial-myofibroblast transition (EMT) of human lens epithelial cells (LECs) induced by transforming growth factor-β2 (TGF-β2) is the main mechanism in the pathogenesis of posterior capsular opacification(PCO).Seeking an effective drug capable of inhibiting this process is important for the prevention and treatment of PCO.Objective The purpose of this study was to investigate the inhibitory effect of rapamycin (RAPA)on the proliferation of human LECs and TGF-β2-induced EMT.Methods Human LEC strain(SRA01/04)was cultured in DMEM with high glucose and 10％ fetal bovine serum.The cells were consequently cultured in serumfree DMEM with 5 mg/L TGF-β2,TGF-β2+10 mg/L RAPA,TGF-β2 + 100 mg/L RAPA,TGF-β2 + 1000 mg/L RAPA or TGF-β2 +10 000 mg/L RAPA for 72 hours,and SRA01/04 cultured in serum-free DMEM were used as control.The proliferation rate(A490)of SRA01/04 in the different groups was detected using the MTT assay and the rate of inhibition of RAPA was calculated.The expressions of the α-smooth muscle actin(α-SMA) and E-cadherin(E-cad)mRNA and protein were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot,respectively.The changes in the expression of α-SMA and E-cad in SRA01/04 were evaluated by Western blot 24,48 and 72 hours after TGF-β2 +400 mg/L RAPA treatment.Results The A490 value of SRA01/04 was 0.680±0.020,0.550±0.013,0.480±0.014,0.400±0.011 and 0.200±0.019 in the control group,TGF-β2 group,TGF-β2 + 10 mg/LRAPA group,TGF-β2 + 100 mg/L RAPA group,TGF-β2 + 1000 mg/L RAPA and TGF-β2 + 10 000 mg/L RAPA group,respectively,showing a gradually declining trend in SRA01/04 rate of proliferation with increasing RAPA concentrations (F =101.920,P =0.000).RT-PCR and Western blot assay showed that the relative expression levels of α-SMA mRNA (α-SMA mRNA/β-actin mRNA)and protein (α-SMA/β-actin)in the cells were significantly increased in the TGF-β2 treatment group.However,with exposure to RAPA,the relative expression levels of α-SMA mRNA and protein were significantly lowered with increasing RAPA concentrations,but the expression levels of E-cad mRNA and protein were raised (α-SMA mRNA:F =294.660,P =0.000 ; α-SMA protein:F =346.950,P =0.000 ; E-cad mRNA:F =264.250,P =0.000 ; E-cad protein:F =317.327,P =0.000).In addition,after exposure to 400 mg/L RAPA,the expression levels of α-SMA protein gradually reduced and those of E-cad protein gradually increased with increasing treatment durations,showing significant differences among the different time points (α-SMA:F =693.864,P =0.000 ;E-cad:F=369.286,P =0.000).Conclusions RAPA can inhibit the proliferation of SRA01/04 in vitro and arrest EMT of SRA01/04 induced by TGF-β2 in a dose-and time-dependent manner.
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Background Ultraviolet irradiation promotes cellular apoptosis by affecting the mitochondrial transmembrane potential,including human lens epithelial cells (LECs).Gene associated with retinoid-interferoninduced mortality-19 (GRIM-19),a cell death regulatory protein,is essential for the assembly and function of mitochondrial complex Ⅰ.However,whether LECs apoptosis induced by ultraviolet irradiation is related to GRIM-19 is still unclear.Objective The purpose of this study was to investigate the relationship between the apoptosis of human LECs caused by ultraviolet with GRIM-19 expression in vitro.Methods Human LEC line(SRA01/04)was cultured in α-MEM containing 10％ fetal bovine serum.The cells were exposed to ultraviolet ray at doses of 0,30,60,90,120 or 150 mJ/cm2 when cell growth reached the logarithmic phase and 80％ confluency.The rate of apoptosis of the cells was assayed using flow cytometry,and the level of expression and relative amount of GRIM-19 protein (GRIM-19/β-actin) were detected by Western blot.The relationship between apoptosis and the GRIM-19/β-actin value among the different treatment groups was compared using One-way ANOVA,and the correlation of LECs apoptosis rate and GRIM-19 expression level was assessed by Pearson linear analysis.Results A significant difference was found in the apoptosis rate among the different treatment groups(F=149.32,P＜0.01).Compared with the 0 mJ/cm2 ultraviolet irradiation group,the apoptosis rate of LECs was significantly increased in the 60,90,120 and 150 mJ/cm2 ultraviolet irradiation groups (q =17.02,-25.20,-29.41,-8.61,P ＜ 0.01).The expression of the GRIM-19 protein in the LECs suspension was enhanced by ultraviolet irradiation at 60,90,120 and 150 mJ/cm2.The relative expression of the GRIM-19 protein (GRIM-19/β-actin) was significantly different among the various groups (F=6.87,P＜0.05),and the GRIM-19/β-actin values in the 60,90,120,150 mJ/cm2 ultraviolet irradiation groups were elevated in comparison with the un-irradiated group(2.01±0.76,2.98± 1.80,3.97± 1.61,2.42± 1.28 vs.0.56±0.23),which showed statistically significant differences (q =4.12,-5.04,-7.09,-3.85,P ＜ 0.01).In addition,a positive correlation was seen between the rate of apoptosis and the expression of the GRIM-19 protein(r=0.71,P＜0.01).Conclusions GRIM-19 is expressed in normal human LECs.The apoptosis of human LECs accompanies the up-regulation of GRIM-19.The expression of GRIM-19 in LECs increases with ultraviolet irradiation in a doseindependent manner.
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Protein-protein interactions between viruses and hosts are common during viral infection and replication. In this study, a cDNA library from larvae of Plutella xylostella was constructed and used for screening of genes encoding proteins interacting with Plutella xylostella granulovirus (PlxyGV) proteins. Two cDNA clones containing genes encoding proteins interacting with PlxyGV PP31 were identified by yeast two-hybrid assays. Sequence analysis showed that the genes encoded homologues of receptor for activated protein C kinase (RACK) and methionine aminopeptidase 2 (MetAP2), respectively. The P. xylostella rack gene and the PlxyGV pp31 was expressed in an E. coli strain to produce proteins fused with a 6-His or a GST tag. It was shown that the rack was expressed as a 38kD peptide as prospected. The 38kD His-tagged peptide was co-purified with GST-PP31 by GST-bind resin in GST-pulldown assays, confirming interaction between the PlxyGV PP31 and the RACK protein of P. xylostella.