The HIV-1 Tat cellular coactivator Tat-SF1 is a general transcription elongation factor.
The human immunodeficiency virus type 1 (HIV-1) Tat protein strongly and specifically stimulates transcription elongation from the HIV-1 LTR and provides an important in vitro model system to study this process. Here we use protein-affinity chromatography to identify cellular factors involved in transcription elongation. A Tat-affinity column bound one transcription factor, Tat-SF1, efficiently and selectively. Tat-SF1 was identified originally as a Tat-specific coactivator, but we show it is a general transcription elongation factor. Our results also reveal the existence of an ATP-inactivatable general elongation factor (AIEF) required for Tat-SF1 activity and for which Tat can substitute functionally.
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Howard Hughes Medical Institute, Program in Molecular Medicine, University of Massachusetts Medical Center, Worcester, Massachusetts 01605, USA.
Green
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D004591:Electrophoresis, Polyacrylamide Gel; D015696:Gene Products, tat / Q000502:physiology; D016325:HIV Long Terminal Repeat / Q000235:genetics; D015497:HIV-1 / Q000235:genetics; D006801:Humans; D010957:Plasmids; D015534:Trans-Activators / Q000502:physiology*; D014158:Transcription, Genetic; D054322:tat Gene Products, Human Immunodeficiency Virus
D015696:Gene Products, tat; C101819:HTATSF1 protein, human; D015534:Trans-Activators; D054322:tat Gene Products, Human Immunodeficiency Virus