In vitro activity of the transcription activation functions of the progesterone receptor. Evidence for intermediary factors.
The human progesterone receptor (hPR) is a ligand-dependent transcription factor which contains two distinct transcription activation functions (TAFs). The full-length hPR and its individual TAFs were overexpressed in the baculovirus system and tested in a HeLa cell-derived in vitro transcription system. hPR stimulated transcription in a ligand-independent manner. When the two TAFs fused to the DNA-binding domain of GAL4 were tested, only the constitutive TAF-1 was functional in vitro, strongly suggesting that the transcriptional activity of baculovirus-expressed hPR comes solely from TAF-1. The GAL-TAF-1 activator was found to self-squelch without affecting basal transcription. A partially purified fraction relieved this self-squelching and, moreover, stimulated transcriptional activation by GAL-TAF-1, while having no influence on basal transcription. These results strongly suggest that the transcriptional activity of GAL-TAF-1 requires a factor(s) distinct from the general transcription factors.
Shemshedini
L
L
Laboratoire de Génétique Moléculaire de Eucaryotes, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Strasbourg, France.
Ji
J W
JW
Brou
C
C
Chambon
P
P
Gronemeyer
H
H
D000818:Animals; D016367:Baculoviridae; D001483:Base Sequence; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D007313:Insecta; D007700:Kinetics; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction; D011980:Receptors, Progesterone / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D016385:TATA Box; D013698:Templates, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
D009838:Oligodeoxyribonucleotides; D011980:Receptors, Progesterone; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D001616:beta-Galactosidase