Transcription activator Domain structure

Figure 8.3 Schematic representation of the general domain structure of a STAT protein. A conserved ( C or con ) domain is located at the N-terminus, followed by the DNA-binding domain (D). Y represents a short se-guence that contains the tyrosine residue phosphorylated by the Janus kinase. The carboxy terminus domain (Tr) represents a transcriptional activation domain...

HSF3, identified in chicken, is induced by c-Myb in the absence of cellular stress (Nakai and Morimoto, 1993 Kanei-Ishii et al., 1997). Another isoform of HSF found in human cells, HSF4, possesses transcription represser properties in vivo (Frejtag et al., 2001). Comparisons of HSF protein structure in these organisms indicate the presence of conserved DNA binding domain and three hydrophobic heptad repeats that constitute the trimerization domain. These domains are located within the amino-terminal region of the protein. The stress-responsive transcriptional activation domain is located in the carboxyl-terminal region of the molecule. 

Figure 3 Designer transcriptional activation domains, (a) Sequences of both natural and non-natural peptidic activation domains. Although little sequence homology exists, all domains are amphipathic and thought to interact with target proteins through helix formation, (b) Structures of nonpeptidic transcriptional activation domains.

Triezenberg, S J. 1995. Structure and function of transcriptional activation domains. Curr. Opin. Genet. Dev. 5, 190-196. 

Proteins that bind to DNA during the course of transcription do so by the same types of interactions that we have seen in protein structures and enzymes— hydrogen bonding, electrostatic attractions, and hydrophobic interactions. Most proteins that activate or inhibit transcription by RNA polymerase II have two functional domains. One of them is the DNA-binding domain, and the other is the transcription-activation domain. 

Peroxisome Proliferator-Activated Receptors. Figure 1 Common structural and functional features of nuclear receptor transcription factors. Consistent with other members of the nuclear receptor superfamily, the PPARs have a modular domain structure consisting of domains A/B, C, D, and E. Each domain is associated with specific functions. 

SHRs are built in a modular structure with similar structure elements. They contain a DNA-binding domain (DBD), a hinge region with a nuclear location signal (NLS), a ligand-binding domain (LBD) and several transcriptional activation functions (Fig. 1). 

Upon binding, the artificial transcription factor recruits the necessary transcriptional machinery for gene activation. (Bottom, left) Ball-and-stick model for a polyamide conjugated to the VP2 activation domain. Symbols are as in Fig. 3.4. (Bottom, right) Structure of the polyamide-VP2 conjugate with the polyproline linker domain in brackets... 

Figure 5.5. A. Schematic illustration of the E. coli RNA polymerase showing the domain structure of the a subunit. The cx-NTD domain is responsible for assembly of RNAP while the a-CTD domain binds DNA and is a target for transcriptional activators. B. The two-hybrid system is based on the interaction of proteins that are fused to the X repressor and NTD domain of the a subunit of RNAP. In the example shown, Gal4 interacts with Gall IP to recruit RNAP to the promoter and activate transcription of the lacZ reporter gene. Figure adapted from Dove and Hochschild (1998).

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