The TATA binding protein, TFIID, plays a central role in the initiation of eukaryotic mRNA synthesis. Here, we present a human cDNA clone for this factor. Comparison of its predicted protein sequence with those from Drosophila and yeast reveals a highly conserved carboxyl-terminal 180 amino acids. By contrast, the amino-terminal region of TFIID has diverged in both sequence and length. A striking feature of the human protein is a stretch of 38 glutamine residues in the NH2-terminal region. Expression of human TFIID in both Escherichia coli and HeLa cells produces a protein that binds specifically to a TATA box and promotes basal transcription; the conserved COOH-terminal portion of the protein is sufficient for both of these activities. Recombinant TFIID forms a stable complex on a TATA box either alone or in combination with either of the general transcription factors, TFIIA or TFIIB. Full-length recombinant TFIID is able to support Sp1 activated transcription in a TFIID-depleted nuclear extract, while a deletion of the NH2-terminal half of the protein is not. These results indicate the importance of the NH2-terminal region for upstream activation functions and suggest that additional factors (co-activators) are required for mediating interactions with specific regulators.

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A Moloney murine leukemia virus based retroviral vector was used to transfer the bacterial neomycin resistance gene (neoR) into feline hematopoietic cells. We reconstituted four cats that had been lethally irradiated with autologous bone marrow that had been infected with the N2 or SAX retroviral vector. Bone marrow cells from all four cats expressed the neoR gene 30 days posttransplant and three of four cats still had the neoR gene and a low level of drug resistant colony- forming unit granulocyte-macrophage after more than 200 days. Two of the four cats unexpectedly developed diabetes mellitus 90 days posttransplantation. The expression of a foreign gene in cats, albeit at a low level, demonstrates that retroviral vectors can be used for gene transfer in noninbred large animal species and may be useful for gene therapy of humans. The development of diabetes mellitus in two of the subjects emphasizes the value of animal models for the study of possible deleterious effects of retroviral vector-mediated gene transfer.

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