Characterization of an interferon-induced gene identified through differential display analysis and the generation of knockout mice defective in their ability to produce interferon-induced guanylate-binding proteins

Differential display analysis was performed on RNA isolated from human Daudi cells that were either untreated or treated with interferon in order to identify interferon-regulated genes. A transcript termed 2-25-A was identified as being up-regulated in interferon-treated Daudi cells. Further studies indicate that this interferon-induced transcript accumulates to elevated levels by four hours after the addition of interferon and the levels remain elevated twenty-four hours post-treatment. The induction of 2-25-A is a direct effect of the interferon treatment and is due to an active increase in the rate of transcription from the 2-25-A gene. In order to study the gene product of the 2-25-A gene, a monoclonal antibody was produced against a portion of the putative 2-25-A protein. This antibody specifically recognizes a protein in cell extracts that is up regulated following interferon treatment.; The generation of knockout mice that are defective in their ability to produce interferon-induced guanylate binding proteins was pursued in order to study the role these genes play in interferon's cellular activities. The genomic organization and expression pattern of the murine genes, GBP-1 and PBP, were determined and transgene constructs were designed to specifically target each of these genes. An embryonic stem cell line has been established, for both GBP-1 and PBP that has undergone homologous recombination with the transgene. Increased viral sensitivity has been observed in a cell line mutated at the GBP-1 gene locus.