A human binding site for transcription factor USF/MLTF mimics the negative regulatory element of human immunodeficiency virus type 1.
Transcriptional regulation of the proviral form of the human immunodeficiency virus type 1 (HIV-1) is exerted by its 5' long terminal repeat (LTR), which contains recognition sites for several cell factors. By gel retardation and DNase I footprinting experiments we have identified a binding site for a human nuclear protein between nucleotides -152 to -174 upstream of transcription start site, in a region previously recognized as a negative regulator of transcription (negative regulatory element, NRE). The recognized sequence contains the dyad symmetry element CACGTG, which represents a binding motif, very conserved through evolution, present in a putative human DNA replication origin (pB48), in the upstream element of the major late promoter (MLP-UE) of adenovirus, and, as transcriptional element, upstream of many eukaryotic genes. Common binding activities exist in human nuclear extracts for pB48, MLP-UE and the HIV-1 LTR; at least three protein species recognize the LTR sequence, of 44 (corresponding to transcription factor USF/MLTF), 70, and 110 kDa, respectively. Chloramphenicol acetyltransferase assays suggest that the USF/MLTF binding site located in the HIV-1 LTR acts as a negative regulator of transcription, and that it contributes to the overall negative function exerted by the NRE. An oligonucleotide corresponding to another characterized human USF/MLTF binding site can functionally replace part of the activity of the NRE. This negative function is exerted both in presence or absence of tat transactivation, in different cell lines, and after PMA stimulation.
Giacca
M
M
International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
Gutierrez
M I
MI
Menzo
S
S
d'Adda di Fagagna
F
F
Falaschi
A
A
D000260:Adenoviruses, Human / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral; D016325:HIV Long Terminal Repeat / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D051720:Upstream Stimulatory Factors
D004279:DNA, Viral; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D014157:Transcription Factors; C497181:USF1 protein, human; D051720:Upstream Stimulatory Factors