Indirect binding of human T-cell leukemia virus type I tax1 to a responsive element in the viral long terminal repeat.
Year: 1989
Type: article
Abstract: Several laboratories have demonstrated that tandem copies of the human T-cell leukemia virus type I 21-base-pair (bp) repeat cloned upstream of either a homologous or heterologous promoter increase transcription in the presence of tax1 protein. In this report, we provide evidence for a second tax1-responsive sequence in the viral long terminal repeat. Analysis of human T-cell leukemia virus type I promoter deletion mutants and plasmids containing cloned oligonucleotide motifs demonstrated that this 47-bp sequence, located between -117 and -163, confers responsiveness to tax1. We further demonstrated that proteins present in HeLa nuclear extracts bind specifically to this tax1-responsive sequence. Mutants that affected in vivo activity also decreased in vitro binding. Using an in vitro binding assay, we demonstrated that tax1 interacts indirectly with the 47-bp sequence, most likely through protein-protein interaction. Thus, while tax1 does not bind directly to DNA to enhance transcription, it may influence sequence-specific responses by interacting with the primary DNA-protein complex.
Source: Molecular and Cellular Biology
Authors: S J Marriott, I Boros, J F Duvall, J N Brady
Institution: National Cancer Institute
Language: English
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2131606860