Mutant U5A cells are complemented by an interferon-alpha beta receptor subunit generated by alternative processing of a new member of a cytokine receptor gene cluster.

Abstract

The cellular receptor for the alpha/beta interferons contains at least two components that interact with interferon. The ifnar1 component is well characterized and a putative ifnar2 cDNA has recently been identified. We have cloned the gene for ifnar2 and show that it produces four different transcripts encoding three different polypeptides that are generated by exon skipping, alternative splicing and differential use of polyadenylation sites. One polypeptide is likely to be secreted and two are transmembrane proteins with identical extracellular and transmembrane domains but divergent cytoplasmic tails of 67 and 251 amino acids. A mutant cell line U5A, completely defective in IFN‐alpha beta binding and response, has been isolated and characterized. Expression in U5A cells of the polypeptide with the long cytoplasmic domain reconstitutes a functional receptor that restores normal interferon binding, activation of the JAK/STAT signal transduction pathway, interferon‐inducible gene expression and antiviral response. The IFNAR2 gene maps at 0.5 kb from the CRFB4 gene, establishing that together IFNAR2, CRFB4, IFNAR1 and AF1 form a cluster of class II cytokine receptor genes on human chromosome 21.

The human papilloma virus (HPV)-18 E6 oncoprotein physically associates with Tyk2 and impairs Jak-STAT activation by interferon-α

“…The IFN-a receptor is present at low numbers on the surface of all cell types and consists of two transmembrane proteins named IFNAR1 and IF-NAR2-2 (Novick et al, 1994;Uze et al, 1990). The IFNAR2 gene generates several alternatively spliced forms, but only the product harboring a long intracytoplasmic domain (IFNAR2-2) is part of a functional IFN-a receptor (Domanski et al, 1995;Lutfalla et al, 1995) (Figure 9). A membrane-proximal 33 amino acid sequence of the cytoplasmic domain of IFNAR1 physically associated with Tyk2 (Colamonici et al, 1994a,b) (Figure 9A).…”

Expression analysis and genomic characterization of human melanoma differentiation associated gene-5, mda-5: a novel type I interferon-responsive apoptosis-inducing gene

“…Based on these considerations, studies of mda-5 induction by IFN were performed using a series of fibrosarcoma cell lines defective in IFN signaling. Derivatives of the 2fTGH fibrosarcoma, wild type in IFN signaling, were compared with U1A, U3A, U4A and U5A cells whose signaling defects could be complemented by expression of tyk2, STAT1, jak1 or IFNAR2, respectively (Pellegrini et al, 1989;Darnell et al, 1994;Lutfalla et al, 1995). While IFN-b treatment induced mda-5 expression in 2fTGH cells, inducible expression of mda-5 was severely impaired in all of the mutant cell lines (Figure 3).…”

High density oligonucleotide array analysis of interferon-α2a sensitivity and transcriptional response in melanoma cells

“…Double stranded cDNA used for the microarray experiments (lines ME15, A375, ME51, ME59, ME67 and D10, see below) was used as template for the amplification of a 370 base pair fragment of the IFNAR2 receptor (Genbank: L42243) (Lutfalla et al, 1995). Amplification was carried out using a commercial kit (Roche Molecular Biochemicals; Cat-Nr.1 939 823) and the oligonucleotides 5′-TCA TAA GGA TGA GGC TGT GAG GAG-3′ (NT 10-34) and 5′-TGT CCA GTG TCT TGG GTA ATG CAC-3′ (NT 380-366) following the manufacturers' instructions.…”