Structural basis for autorepression of retinoid X receptor by tetramer formation and the AF-2 helix

Article Abstract:

The inactivated tetramer structures of the RXR alpha ligand-blinding domain in the absence or presence of a nonactivating ligand is reported. The structures show that the RXR LBD tetramer forms a compact, disc-shaped complex made up of two symmetric dimers packed along helices 3 and11. The structural basis for autorepression of retinoid X receptor by tetramer formation and the AF-2 helix.

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Promoter opening by sigma(super.54) and sigma(super.70) RNA polymerases: sigma factor-directed alterations in the mechanism and tightness of control

Article Abstract:

Promoter opening by sigma(super.54) and sigma(super.70) RNA polymerases is discussed. Transcription control at the melting step has been studied using band shift, crosslinking and transcription experiments on diverse DNA probes with two bacterial RNA polymerase holoenzymes. These holoenzymes differ in ways they regulate melting. The two sigma factors were found to modify the same intrinsic opening pathway to set up different mechanisms of regulation of transcription.

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Crystal structure of the human Pax6 paired domain-DNA complex reveals specific roles for the linker region and carboxy-terminal subdomain in DNA binding

Article Abstract:

Study of the crystal structure of the human Pax6 paired domain-DNA complex shows certain roles for the carboxy-terminal subdomain and the linker region in DNA binding. Pax6, a transcription factor that contains the two-part paired DNA-binding domain has critical roles in development of several parts of the body. Structure information gives background for understanding paired domain-DNA interactions, for modeling protein-protein interaction of the Pax family proteins, and for analyzing mutations that map in the carboxy-terminal regions of the paired domain and the linker. Knowing the Pax6 structure makes it possible to establish the docking position for the amino-terminal subdomain seen in cocrystals of the Drosophila Prd Pax of paired domain-DNA recognition. Information about how the paired linker region and carboxy terminal subdomain contact DNA has been found.

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