Dimerization and the control of transcription by Krüppel.
Krüppel (KR), a Drosophila zinc finger-type transcription factor, can both activate and repress gene expression through interaction with a single DNA-binding site. The opposite regulatory effects of KR are concentration-dependent, and they require distinct portions of KR such as the N-terminal region for activation and the C-terminal region for repression. Here we show that KR is able to form homodimers through sequences located within the C terminus. When these sequences were fused to separated functional parts of the yeast transcription factor GAL4, they reconstituted a functional transcriptional activator on dimerization in vivo. Our results suggest that the KR monomer is a transcriptional activator. At higher concentration KR forms a homodimer and becomes a repressor that functions through the same target sequences as the activator.
Sauer
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F
Abt. Molekulare Entwicklungsbiologie, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.
Jäckle
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H
D000818:Animals; D001483:Base Sequence; D001704:Biopolymers; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000502:physiology*; D004330:Drosophila; D029721:Drosophila Proteins; D005656:Fungal Proteins; D051741:Kruppel-Like Transcription Factors; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000502:physiology; D014157:Transcription Factors / Q000737:chemistry / Q000502:physiology*
D001704:Biopolymers; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; C497244:Kr protein, Drosophila; D051741:Kruppel-Like Transcription Factors; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors