Vaccinia virus has been used as a vector to express foreign genes for the production of functional and posttranslationally modified proteins. A procedure is described here that allows the rapid native purification of vacciniaexpressed proteins fused to an amino-terminal tag of six histidines. Extracts from cells infected with recombinant vaccinia virus are loaded onto Ni2+ nitrilotriacetic acid (Ni2+-NTA)-agarose and histidine-tagged proteins are selectively eluted with imidaole-containing buffers. In the case of the human serum response factor (SRF), a transcription factor involved in the regulation of the c-fos protooncogene, the vaccinia-expressed histidine-tagged SRF (SRF-6His) could be purified solely by this step to >95% purity. SRF-6His was shown to resemble authentic SRF by functional criteria: it was transported to the nucleus, bound specifically the c-fos serum response element, interacted with the p62TCF protein to form a ternary complex, and stimulated in vitro transcription from the serum response element. Thus, the combination of vaccinia virus expression and affinity purification by Ni2+|NTA chromatography promises to be useful for the production of proteins in a functional and posttranslationally modified form.

Plasmids expressing different domains of the hepatitis C virus (HCV) envelope E2 glycoprotein from a genotype 1a isolate were constructed to compare the immunogenic potential of E2 in nucleic acid-based immunizations. One plasmid, pCIE2t, expressed a C-terminally truncated form of E2, while others, pS2.SE2A to pS2.SE2E, encoded the adjacent 60-amino-acid (aa) sequences of E2 (inserts A to E) expressed as a fusion with the hepatitis B virus surface antigen. BALB/c mice were given injections of the plasmids intramuscularly (i.m.) or intraepidermally (i.e.) via a gene gun (biolistic introduction), and induced humoral immune responses were evaluated. The i.e. injections resulted in higher seroconversion rates and antibody titers, up to 100-fold, than did the i.m. injections (P ‫؍‬ 0.01 to 0.04). Three restricted immunogenic domains, E2A (aa 384 to 443), E2C (aa 504 to 555), and E2E (aa 609 to 674), that yielded antibody titers ranging from 1:59 to >1:43,700 could be identified. Subtype 1a-and 1b-derived E2 antigens and synthetic peptides were used in Western blot and enzyme-linked immunosorbent assay analyses, which revealed that the cross-reactivity of the plasmid-induced antibodies was linked both to the type of antigen expressed and to the injection mode. Induced anti-E2 antibodies could immunoprecipitate noncovalent E1E2 complexes believed to exist on the surface of HCV virions. This study allowed us to identify restricted immunogenic domains within E2 and demonstrated that different routes of injection of HCV E2 plasmids can result in quantitatively and qualitatively different humoral immune responses.

Small fragments of the DNA of human papillomavirus type 16 (HPV-16) were randomly cloned into the bacteriophage fd which expresses the resulting peptides as part of its capsid. Antisera raised against different HPV-16 fusion proteins were used for screening of the phage clones and the reacting peptides were determined by sequencing the inserted HPV-16 DNA fragments of the positive recombinants. Seroreactive regions of the proteins derived from the E4, E6, E7 (two regions) and L1 (three regions) open reading frames could be found by this approach. Of these seven regions, four were defined by at least two overlapping inserts, thus limiting the domains to between 10 and 15 amino acids. In the case of the E4 open reading frame, the same region identified by immunoscreening was also found when synthetic overlapping octapeptides were tested by ELISA with the anti-E4 antiserum. Using an approach to predict 'receptor-like' regions within the respective proteins, five of the seven regions were also identified. From the data on these regions, synthetic peptides were produced and used for the detection of antibodies against HPV-16 proteins in human sera by ELISA.

The structure of thyroglobulin mRNA was analyzed in an inbred herd of Afrikander cattle with hereditary goitre. Northern transfer of RNA from affected animals revealed both a shorter (approximately 7100 bases) and a normal‐sized (approximately 8200 bases) thyroglobulin mRNA when hybridized to bovine thyroglobulin cDNA clones. S1 nuclease mapping experiments established that 1100 bases are deleted in the 5′ region of the smaller mRNA. Electron microscopy of RNA from animals with goitre hybridized to a bovine genomic DNA clone showed that the region deleted corresponds to exon 9 of the thyroglobulin gene. Southern blot analysis of the exon 9 region revealed differences between affected and control animals with the enzymes PstI and TaqI. Although they could reflect a linkage disequilibrium between the mutation and restriction fragment length polymorphism, it is noteworthy that these differences map in the region of the exon 9/intron 9 junction. Our results show that a genetic lesion in the thyroglobulin gene causes aberrant splicing of the pre‐mRNA, and suggest that the responsible mutation is at the exon 9/intron 9 junction.

The sequence of the first 2831 nucleotides of bovine thyroglobulin mRNA has been determined from the analysis of a cDNA clone. Following a 41‐nucleotide 5′ untranslated sequence, a single open‐reading frame encoding 930 amino acids was observed. This corresponds to the aminoterminal third of thyroglobulin, preceded by a putative signal peptide of 19 amino acids. The protein sequence was found to be essentially made of the sevenfold repetition of a 60‐amino‐acid‐long building unit, interrupted at fixed positions by unrelated segments of variable length. The presence of an internal homology within the repetitive unit itself suggests that the 5′ region of the thyroglobulin gene has evolved from the initial duplication of a relatively short sequence, followed by the serial duplication of the resulting unit. The tyrosine residue at position five has been assigned an important hormonogenic function [Mercken, L., Simons, M.‐J. and Vassart, G. (1982) FEBS Lett. 149, 285–287]. This residue is flanked by sequence elements related to the repeated unit, suggesting that the hormonogenic domain evolved also from the basic ancestor sequence.