Genomic and cDNA clones corresponding to 9-27, a member of the human 1-8 gene family highly inducible by a-and y-interferons (IFNs), have been isolated and characterized. A 1.7-kilobase genomic clone contains a complete functional gene with two exons, encoding a 125-amino acid polypeptide of unknown function. The 5' flanking region of the gene contains a 13-base-pair IFN-stimulable response element (ISRE), homologous to the ISREs of the 6-16, ISG 15, and ISG 54 genes, which are predominantly inducible by IFN-a,4. Analysis of constructs containing native and mutated ISREs suggests that this motif is essential for the response of 9-27 to IFN-y as well as IFN-a. Furthermore, the 9-27 (GGAAATAGAAACT) and 6-16 (GGGAAAATGAAACT) ISREs can each confer a response to both types of IFN when placed on the 5' side of a marker gene. Since the 6-16 gene does not normally respond to IFN-y, the context of the ISRE must determine the specificity of the response.Highly homologous response elements for a-and ,B-interferons (IFNs) have been identified in the 5' flanking regions of several IFN-inducible genes (1-6). They have partial homology to other enhancer elements and bind at least three IFN-modulated factors and a constitutive factor(s). The former appear with different kinetics after IFN treatment and are probably involved not only in the induction of transcription but also in its down-regulation and subsequent refractory state (refs.

Recent reports have shown that synthesis of certain recombinant proteins in Escherichia coli results in the production of intracellular inclusion bodies. These studies have not analyzed the structure of the inclusion body especially regarding the intermolecular forces holding it together. We have examined structural aspects of inclusion bodies made in E. coli as a result of high level expression of the eukaryotic protein, calf prochymosin. Prochymosin is a monomeric protein containing three disulfide bridges. It was expressed at up to 20% of cell protein from a plasmid containing the E. coli tryptophan promoter, operator and ribosome binding site. Proteins in the inclusion bodies were analysed by Western blotting of SDS‐polyacrylamide gels. When experiments were done using conditions which preserved the in vitro state of thiol groups, inclusions were shown to be composed of multimers of prochymosin molecules which were interlinked partly by disulfide bonds. The inclusion bodies also contained a high concentration of reduced prochymosin. The presence of intermolecular disulfides probably contributes to the difficulty of solubilizing recombinant prochymosin during its purification from E. coli.