Abstract: DNA sequences, recombinant DNA molecules and hosts transformed with them which produce polypeptides displaying a biological or immunological activity of human interferon, the genes coding for these polypeptides and methods of making and using these molecules, hosts, genes and polypeptides. The DNA sequences are characterized in that they code for a polypeptide displaying a biological or immunological activity of human interferon. In appropriate hosts these DNA sequences and recombinant DNA molecules permit the production and identification of genes and polypeptides displaying a biological or immunological activity of human interferon and their use in antiviral and antitumor or anticancer agents.

Abstract: A DNA molecule having a gene expression repressing function derived from human T-cell leukemia virus type I (HTLV-I) existing in a region which is missing in a mutant provirus that is expressing p21Xm RNA but exists in the genome of a complete provirus, and a plasmid including the DNA molecule are provided. Furthermore, a novel protein (TRP-1) which specifically binds to U5RE and a structural gene for the protein is provided, which can be useful for elucidation of the transcription repression activity and elucidation of the oncogenesis mechanism of neurocytes, in which a transcriptional repressive region (U5RE) existing in the U5 region of human T-cell leukemia virus type I gene LTR is involved. Furthermore, an expression vector including the gene, a transformant into which the expression vector is introduced, and a process for producing the TRP-1 protein using the transformant are provided.