ABSTRACT
Objective: To discuss the antiviral effect, the inhibitory effect on LINE-1 retrotransposon activity and the redection of interferon production signal pathway of restriction factor SAMHD1 of the primates, and to provide the basis for further study of the SAMHD1 of the primates. Methods: The U937 cells stably expressing the SAMHD1 of primates were established; the U937-control cells established with pLVX -puro were used as negative control group, and the U937-SAMHD1 cells stably expressing the SAMHD1 protein of the different primates were used as experimental groups; the cells were treated with PMA to induce cell differentiation. The virus infection rates of HIV-1 in the cells in various groups were determined by flow cytometry. The HEK293T cells transfected with the expression plasmid of SAMDH1 were used as control group, and the cells co-transfected with the SAMHD1 and HIV-2/SIV Vpx expression plasmids were used as experimental groups. The cells were obtained 48 h after transfection, and the expression levels of SAMHD1 protein were determined by Western blotting method. The intracellular location of SAMHD1 protein was determined by immunofluorescence. The HEK293T cells transfected with LINE-1-GFP report plasmid were used as control group, and the cells co-transfected with LINE-1-GFP and SAMHD1 expression plasmids were used as experimental groups. The rates of GFP positive cells (activity of SAMHD1 to LINE-1 transposon) were determined by flow cytometry. The HEK293T cells transfected with IFN- Luc report plasmid were used as control group, and the cells co-transfected with IFN-Luc and pSAMHDl expression plasmids were used as experimental groups. The expression levels of luciferase in HEK293T cells were determined by chemiluminescence instrument. Results: Compared with negative control group, the virus infection rates of HIV-1 in experimental groups with stable expression of SAMHD1 in the primates were significantly decreased (P<0. 01). Compared with control group, the expression levels of SAMHD1 protein of the primates in experimental groups were decreased (P<0. 05 or P<0. 01). The immunofluorescence results showed that the SAMHD1 protein of the primates was localized in the nucleus. Compared with control group, the rates of GFP positive cells (activity of SAMHD1 to LINE-1 transposon) in experimental groups were significantly decreased (P< 0.05 or P<0.01). Compared with control group, the expression levels of luciferase in the HEK293T cells in experimental groups were significantly decreased (P<0. 05). Conclusion: The SAMHD1 protein of the different primates can resist the HIV-1 infection, inhibit the LINE-1 retrotransposon and antagonize the IFN production by natural immune system.
ABSTRACT
Purpose Investigating the significance of ZO-1 different domains in the invasion and metastasis of gastric carcinoma (GC).Methods A tissue microarray that simulates the invasion and metastasis process of GC was created,and immunohistochemistry was performed to detect the expression of ZO-1 (α-pan),ZO-1 (α +) and ZO-1 (ZU5).Results The GC cell exhibited aberrant expression of ZO-1 (α-pan),ZO-1 (α +) and ZO-1 (ZU5) from membrane translocated to cytoplasm or no expression.The aberrant degree was increased with the invasion,however,was decreased in metastatic lymph node.The aberrant expression was associated with histological types.Conclusion The aberrant expression of ZO-1 (α-pan),ZO-1 (α +) and ZO-1 (ZU5),from membrane translocated to cytoplasm or no expression suggest that domains of PDZ3,GUK,SH3,ZU5 and alpha motif in ZO-1 might be involved in the invasion and metastasis of GC and maintaining of GC phenotype.The aberrant expression of these domains may be the one mechanism of ZO-1 involved in EMT or MET.