A novel, transformation-relevant activation domain in Fos proteins

Titelangaben

Funk, M. ; Poensgen, B. ; Graulich, W. ; Jérôme, Valérie ; Müller, Rolf:
A novel, transformation-relevant activation domain in Fos proteins.
In: Molecular and Cellular Biology. Bd. 17 (1997) Heft 2 . - S. 537-544.
ISSN 1098-5549
DOI: https://doi.org/10.1128/MCB.17.2.537

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Abstract

We have previously demonstrated that transformation by Fos is critically dependent on an intact DNA-binding domain (bZip) and a functional N-terminal transactivation motif (N-TM). We now show that a novel motif (C-terminal transactivation motif [C-TM]) near the C terminus also plays an important role in both transformation and the activation of AP1-dependent transcription and that the hydrophobic amino acids in the C-TM are functionally essential. The C-TM is the most crucial element in the C-terminal transactivation domain in Fos, as indicated by its relative strength and context-independent function. The C-TM is clearly different from the previously identified HOB2 domain, located N terminally to the C-TM, and the C-terminally positioned TATA-binding protein-binding domain. We also show that the C-terminal transactivation domain strongly synergizes with the HOB1-like N-TM, even when both domains are present on different proteins within a dimeric complex, and that the C-TM plays a crucial role in this cooperation. These observations can be corroborated in a model in which multiple contacts with the basal machinery are established either to stabilize the transcription complex or to facilitate its sequential assembly.