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Integration of HIV-1 into the human genome, which is catalyzed by the viral protein integrase (IN), preferentially occurs near transcriptionally active genes. Here we show that p300, a cellular acetyltransferase that regulates chromatin conformation through the acetylation of histones, also acetylates IN and controls its activity. We have found that p300(More)
Long-standing evidence indicates that quiescent human peripheral blood T lymphocytes (PBLs) do not support efficient HIV infection. In resting PBLs, reverse transcription of viral RNA takes longer than in activated cells, partially because formation of the late products of reverse transcription is decreased by RNA binding by apolipoprotein B mRNA-editing(More)
The six members of the E2F family of transcription factors play a key role in the control of cell cycle progression by regulating the expression of genes involved in DNA replication and cell proliferation. E2F-1, -2, and -3 belong to a structural and functional subfamily distinct from those of the other E2F family members. Here we report that E2F-1, -2, and(More)
Here we report a novel, noncompetitive mechanism that links acetylation and ubiquitination, in which the association of transcription factor E2F-1 with the cellular coactivator and acetyltransferase p300 determines its acetylation and subsequent ubiquitination. By using an antibody specifically recognizing the acetylated form of E2F-1 (AcE2F-1), we found(More)
The human transcription factor USF, purified from HeLa cells, and its recombinant 43-kDa component bind to the long terminal repeat (LTR) of human immunodeficiency virus type 1. The proteins footprint over nucleotides from position -173 to -157 upstream of the transcription start site, generating strong DNAse I hypersensitivity sites at the 3' sides on both(More)
Starting from a pool of 10(13) RNA sequences, we isolated a number of TAR RNA variants after nine rounds of selection by binding to recombinant Tat in vitro (SELEX procedure). Sequence analysis of part of the selected molecular species indicated that two TAR variants (clones A and B) were, respectively, represented five and four times. These two groups of(More)
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(More)
The transactivator protein of human immunodeficiency virus type 1 (HIV-1) (Tat) is a powerful activator of nuclear factor-kappaB (NF-kappaB), acting through degradation of the inhibitor IkappaB-alpha (F. Demarchi, F. d'Adda di Fagagna, A. Falaschi, and M. Giacca, J. Virol. 70:4427-4437, 1996). Here, we show that this activity of Tat requires the function of(More)
Human immunodeficiency virus type 1 (HIV-1) Tat transactivates viral genes and is released by infected cells, acting as a soluble mediator. In endothelial cells (EC), it activates a proangiogenic program by activating vascular endothelial growth factor receptor type 2 (VEGFR-2) and integrins. A structure-activity relationship study was performed by(More)
BACKGROUND An essential event during the replication cycle of HIV-1 is the integration of the reverse transcribed viral DNA into the host cellular genome. Our former report revealed that HIV-1 integrase (IN), the enzyme that catalyzes the integration reaction, is positively regulated by acetylation mediated by the histone acetyltransferase (HAT) p300. (More)