Mediators of activation of fushi tarazu gene transcription by BmFTZ-F1.
Transcriptional activation by many eukaryotic sequence-specific regulators appears to be mediated through transcription factors which do not directly bind to DNA. BmFTZ-F1 is a silkworm counterpart of FTZ-F1, a sequence-specific activator of the fushi tarazu gene in Drosophila melanogaster. We report here the isolation of 18- and 22-kDa polypeptides termed MBF1 and MBF2, respectively, that form a heterodimer and mediate activation of in vitro transcription from the fushi tarazu promoter by BmFTZ-F1. Neither MBF1, MBF2, nor a combination of them binds to DNA. MBF1 interacts with BmFTZ-F1 and stabilizes the BmFTZ-F1-DNA complex. MBF1 also makes direct contact with TATA-binding protein (TBP). Both MBF1 and MBF2 are necessary to form a complex between BmFTZ-F1 and TBP. We propose a model in which MBF1 and MBF2 form a bridge between BmFTZ-F1 and TBP and mediate transactivation by stabilizing the protein-DNA interactions.
Li
F Q
FQ
Department of Genetics, Graduate University for Advanced Studies, Shizuoka-ken, Japan.
Ueda
H
H
Hirose
S
S
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D051717:Fushi Tarazu Transcription Factors; D015870:Gene Expression; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins; D006801:Humans; D007301:Insect Hormones / Q000096:biosynthesis* / Q000235:genetics; D019476:Insect Proteins; D007700:Kinetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D008970:Molecular Weight; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D054339:Steroidogenic Factor 1; D016385:TATA Box; D035181:TATA-Box Binding Protein; D014157:Transcription Factors / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D007301:Insect Hormones; D019476:Insect Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D054339:Steroidogenic Factor 1; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; C497169:ftz protein, Drosophila; C499713:nuclear hormone receptor FTZ-F1, Bombyx mori; C499712:nuclear hormone receptor FTZ-F1, Drosophila; D004247:DNA