Identification of Alpha Interferon-Induced Genes Associated with Antiviral Activity in Daudi Cells and Characterization of IFIT3 as a Novel Antiviral Gene
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ABSTRACT: A novel assay was developed for Daudi cells in which the antiviral (AV) and antiproliferative (AP) activities of interferon (IFN) can be measured simultaneously. Using this novel assay, conditions allowing IFN AV protection but no growth inhibition were identified and selected. Daudi cells were treated under these conditions, and gene expression microarray analyses were performed. The results of the analysis identified 25 genes associated with IFN-alpha AV activity. Upregulation of 23 IFN-induced genes was confirmed by using reverse transcription-PCR. Of 25 gene products, 17 were detected by Western blotting at 24 h. Of the 25 genes, 10 have not been previously linked to AV activity of IFN-alpha. The most upregulated gene was IFIT3 (for IFN-induced protein with tetratricopeptide repeats 3). The results from antibody neutralizing experiments suggested an association of the identified genes with IFN-alpha AV activity. This association was strengthened by results from IFIT3-small interfering RNA transfection experiments showing decreased expression of IFIT3 and a reduction in the AV activity induced by IFN-alpha. Overexpression of IFIT3 resulted in a decrease of virus titer. Transcription of AV genes after the treatment of cells with higher concentrations of IFN having an AP effect on Daudi cells suggested pleiotropic functions of identified gene products. Gene expression was initially measured in four Daudi cell groups (3 x 10(6) in 10 ml of RPMI) treated for 24 h at IFN concentrations selected to allow comparison of gene activity in AV activity environments with environments in which no AV activity was observed. These treatment groups were: (i) 0.0036 ng of IFN-alpha2c/ml (n=5) (allowing AV activity only); (ii) 0.00036 ng of IFN-alpha2c/ml (n=5) (no AV observed); (iii) 0.036 ng of HY-2/ml (n=3) (allowing AV activity); and (iv) 0.0036 ng of HY-2/ml (n=3) (no AV observed). To refine the list of genes associated with AV activity, samples showing AP phenotype (achieved by treatment with IFN-alpha2c [0.36 ng/ml] (n=3) or HY-2 [36 ng/ml]) (n=3) were compared to identically treated samples manipulated to display the AV phenotype through subsequent neutralization with anti-IFNAR1 MAb 64.10 (1 ug/ml) (n=6). Further analysis of gene expression profiles after 6 h of incubation helped indicate genes associated with early roles in IFN-induced AV mechanisms (n=6).
ORGANISM(S): Homo sapiens
SUBMITTER: Hana Schmeisser
PROVIDER: E-GEOD-32517 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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