Dimerization of the interferon type I receptor IFNaR2-2 is sufficient for induction of interferon effector genes but not for full antiviral activity.
We constructed chimeric receptors wherein the extracellular domain of the erythropoietin receptor (EpoR) was fused to the transmembrane and intracellular domains of the interferon (IFN) type I receptor subunits, IFNaR1 or IFNaR2-2. Transfection into 2fTGH and Tyk2-deficient 11,1 cells showed that EpoR/IFNaR2-2 alone was able to transduce a signal upon stimulation with erythropoietin (Epo), as judged by induction of the interferon type I-inducible 6-16 promoter. In contrast, protection against infection with encephalomyocarditis virus or vesicular stomatitis virus was reduced or absent, respectively. To further investigate the role of IFNaR1 in the induction of an antiviral state, we analyzed the Epo- versus IFNalpha-induced transcription of a set of genes, involved in antiviral protection. Up to 24 h after stimulation with Epo or IFNalpha, comparable transcription of the p56, dsRNA-dependent protein kinase, 2'-5'A synthetase, and MxA genes was seen. However, at later time points, only in the case of Epo induction, a sharp decrease of mRNA levels was observed. Western blotting analysis of dsRNA-dependent protein kinase showed a similar pattern at the protein level. Taken together, our results imply a role for IFNaR1 in the induction of sustained mRNA and protein levels that are likely required for optimal antiviral activity.
Pattyn
E
E
Flanders Interuniversity Institute for Biotechnology, Department of Medical Protein Research, Faculty of Medicine, University of Ghent, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
Van Ostade
X
X
Schauvliege
L
L
Verhee
A
A
Kalai
M
M
Vandekerckhove
J
J
Tavernier
J
J
D000469:Alkaline Phosphatase / Q000378:metabolism; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D005354:Fibrosarcoma / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D016898:Interferon-alpha / Q000378:metabolism*; D016899:Interferon-beta / Q000378:metabolism*; D008565:Membrane Proteins; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D053633:Receptor, Interferon alpha-beta; D017467:Receptors, Erythropoietin / Q000378:metabolism; D017471:Receptors, Interferon / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection
C507964:IFNAR1 protein, human; C508033:IFNAR2 protein, human; D016898:Interferon-alpha; D008565:Membrane Proteins; D012333:RNA, Messenger; D017467:Receptors, Erythropoietin; D017471:Receptors, Interferon; D011993:Recombinant Fusion Proteins; D053633:Receptor, Interferon alpha-beta; D016899:Interferon-beta; D000469:Alkaline Phosphatase