Abstract: The present invention provides a method of preparing a plasmid having both the ability of expressing retroviral genes and the ability of effecting the after-translational processing of the encoded products, and the resultant plasmid and the expression products thereof. The method of the present invention is to prepare a plasmid by insertion-linking a cDNA fragment containing at least the protease gene from among retroviral genes with a highly expressing gene or a gene direct expressing vector, thereby causing expression of the retroviral genes, and at the same time, to process said expression product itself with the protease in that expression product, thereby mass-producing three kinds of core protein encoded by vaq gene, and three kinds of enzymes encoded by pol gene, in the form of individual single mature or active proteins.

Abstract: Disclosed is a substantially pure HIV antigen comprising a Gag-Env fusion otein consisting of a Gag peptide fused at its C-terminus to an Env peptide, wherein the Gag peptide comprises a contiguous sequence of at least ten amino acids of the amino acid sequence represented by Gag (308-437) and the Env peptide comprises a contiguous sequence of at least a part of the amino acid sequence represented by Env (512-699), the part containing at least one epitope which is reactive to an HIV antibody. The gag-env fusion DNA corresponding to the HIV antigen of the present invention allows the production of the desired high antigenicity HIV antigen in high yield. Therefore, the HIV antigen of the present invention can be advantageously used as an active component for a diagnostic reagent, a vaccine, an antibody preparation and a therapeutic reagent for AIDS. Also disclosed is a substantially pure HIV antigen comprising a Gag protein SEQ ID No.:1 coded for by the entire gag gene.

Abstract: The present invention provides a method of preparing a plasmid having both the ability of expressing retroviral genes and the ability of effecting the after-translational processing of the encoded products, and the resultant plasmid and the expression products thereof. The method of the present invention is to prepare a plasmid by insertion-linking a cDNA fragment containing at least the protease gene from among-retroviral genes with a highly expressing gene or a gene direct expressing vector, thereby causing expression of the retroviral genes, and at the same time, to process said expression product itself with the protease in that expression product, thereby mass-producing three kinds of core protein encoded by gag gene, and three kinds of enzymes encoded by pol gene, in the form of individual single mature or active proteins.

Abstract: Disclosed is the construction, expression, and purification of chimeric human immunodeficiency virus type 1 (HIV-1) Gag-Env fusion proteins. Gag-Env chimeras were generated by fusing the amino terminus (amino acids 512-611) of the Env protein to the carboxyl terminus of the Gag protein (either amino acids 121-406 or 308-406). These proteins were overexpressed in Escherichia coli, purified, and their immunologic properties ascertained. Both chimeric proteins displayed immunoreactivity towards antisera obtained from HIV-1 seropositive patients. These HIV-1 Gag-Env fusion proteins should provide useful antigens for the detection of HIV-1-specific antibodies.

Abstract: Disclosed is a method for producing retroviral proteins which are protease, everse transcriptase and endonuclease. The method is characterized by the consecutive expression and processing of retroviral genes by the stepwise cultivation of hosts transformed with a vector constructed to carry retroviral gene fragments comprising at least a protease gene and one or more of the other genes coding for retroviral proteins. The retroviral proteins of this invention are used as specific reagents for the diagnosis of retroviral disease, e.g., AIDS, malignant tumors and so forth, also may be used as the basis for research and development of antiviral agents and a vaccine against the above infectious diseases, and for genetic engineering.

Abstract: Disclosed is a DNA sequence containing a DNA segment coding for Achromobacter protease I (API) or variants thereof (referred to as T-API); a recombinant DNA constructed by introducing the DNA sequence in an expression vector so as to express the T-API; a transformant bearing the recombinant DNA; a process for producing the API which comprises cultivating the transformant, accumulating the T-API in a culture product, and recovering the same: and a protein of T-API. The cells transfected or transformed with the DNA sequence of the present invention allow for the production of a large amount of precursor protein of the T-API or the mature peptide.

Abstract: An expression vector carrying a gene coding for a phosphate-binding protein has been found to have a strong gene expression. The expression vector can be produced by transforming a bacterium belonging to Enterobacteriaceae with a recombinant vector carrying a DNA fragment containing a gene coding for a phosphate-binding protein to form transformants, selecting the transformants containing the desired recombinant vector from said transformants, and isolating the desired recombinant vector from the selected transformants. The expression vector is useful for producing polypeptides.