Binding of host-cell factors to DNA sequences in the long terminal repeat of human T-cell leukemia virus type I: implications for viral gene expression

Journal Article · Tue Mar 01 00:00:00 EST 1988 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.85.5.1457· OSTI ID:6619254

Nyborg, J K; Dynan, W S; Chen, I S.Y.; Wachsman, W

Efficient expression of human T-cell leukemia virus type I (HTLV-I) genes requires both host and viral proteins and is dependent on DNA sequences in the proviral long terminal repeats (LTRs). The authors have used DNase I-protection assays (footprinting) to construct a map of protein-DNA interactions over a 250-nucleotide region of the LTR upstream of the start site for viral RNA synthesis. They find that a host factor (host expression factor 1, or HEF-1) binds to the imperfect 21-nucleotide repeats that have previously been implicated in HTLV-I gene expression. HEF-1 binding activity is present in preparations from both lymphoid and nonlymphoid cells lines. However, the boundaries of the protected regions and the presence of a flanking DNase-hypersensitive site vary with cell type. Several regions of binding are detected in addition to the HEF-1 sites, including a complex group of sites 40-90 nucleotides upstream of the RNA start site. A comparison of HTLV-I transformed T lymphocytes that do and do not express the viral trans-activating protein p40/sup xI/ shows that none of the observed features of the DNase I footprint pattern correlate directly with the presence of this protein in the extract. These results suggest (i) that the primary recognition of promoter elements in the HTLV-I LTR involves specific interactions with host-cell proteins and (ii) that p40/sup xI/ influences the activity of one or more of these proteins, rather than interacting directly with the DNA.

• Research Organization: Univ. of Colorado, Boulder (USA)
• OSTI ID: 6619254
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 85:5
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
DNA
CROSS-LINKING
LEUKEMIA VIRUSES
DNA SEQUENCING
PROTEINS
DNA-ASE
GENE REGULATION
GENE REPRESSORS
HELA CELLS
HYBRIDIZATION
LYMPHOCYTES
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PHOSPHORUS 32
ANIMAL CELLS
ANIMALS
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BODY FLUIDS
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CONNECTIVE TISSUE CELLS
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ENZYMES
ESTERASES
HYDROLASES
ISOTOPES
LEUKOCYTES
LIGHT NUCLEI
MAMMALS
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MICROORGANISMS
NUCLEI
NUCLEIC ACIDS
NUCLEOPROTEINS
ODD-ODD NUCLEI
ONCOGENIC VIRUSES
ORGANIC COMPOUNDS
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PHOSPHORUS ISOTOPES
POLYMERIZATION
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550201* - Biochemistry- Tracer Techniques