[Voyage en Italie : 1824-1830]. , Musée des Etudes, Etrusques : [un motif de vase] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 267

[Voyage en Italie : 1824-1830]. , [Musée du Vatican, détail d'une composition ornementale] : [un motif] : [dessin] / [Henri Labrouste]

Référence bibliographique : Weigert, 619

[Voyage en Italie : 1824-1830]. , [Cuve de bain en basalte, socle à motifs de griffons, motif de palmette] au Musée du Vatican : [trois motifs] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 617

Biochemical properties of RuvBD113N: a mutation in helicase motif II of the RuvB hexamer affects DNA binding and ATPase activities.

Many DNA helicases utilise the energy derived from nucleoside triphosphate hydrolysis to fuel their actions as molecular motors in a variety of biological processes. In association with RuvA, the E. coli RuvB protein (a hexameric ring helicase), promotes the branch migration of Holliday junctions during genetic recombination and DNA repair. To analyse the relationship between ATP-dependent DNA helicase activity and branch migration, a site-directed mutation was introduced into the helicase II motif of RuvB. Over-expression of RuvBD113N in wild-type E. coli resulted in a dominant negative UVs phenotype. The biochemical properties of RuvBD113N were examined and compared with wild-type RuvB in vitro. The single amino acid substitution resulted in major alterations to the biochemical activities of RuvB, such that RuvBD113N was defective in DNA binding and ATP hydrolysis, while retaining the ability to form hexameric rings and interact with RuvA. RuvBD113N formed heterohexamers with wild-type RuvB, and could inhibit RuvB function by affecting its ability to bind DNA. However, heterohexamers exhibited an ability to promote branch migration in vitro indicating that not all subunits of the ring need to be catalytically competent.

[Voyage en Italie : 1824-1830]. , Musée des Études, mosaïque de Pompeia : [un motif : composition architecturale avec lutteur et poule] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, n. d.

[Voyage en Italie : 1824-1830]. , [Musée des Études ?] : [un motif représentant deux biches] : [dessin] / [Henri Labrouste]

Référence bibliographique : Weigert, 266

[Voyage en Italie : 1824-1830]. , [Voie des Tombeaux : tombeau dit "des Guirlandes"] : [élévation du motif à droite du tombeau] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, n. d.

[Voyage en Italie : 1824-1830]. , [Peinture murale dans la maison des Vestales] au Huitième de l'Exécution : [un motif d'architecture feinte] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 423

[Voyage en Italie : 1824-1830]. , Peintures à Pompeia : [un motif d'architecture feinte, avec deux angelots et un personnage masculin] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 424

[Voyage en Italie : 1824-1830]. , [Détails de peintures décoratives] : [un motif avec guirlande de lauriers] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 426

[Voyage en Italie : 1824-1830]. , [Peinture décorant la niche d'un laraire] d'après l'ouvrage de M. Mazois : [un motif représentant une divinité, assise sur un lit et tenant une corne d'abondance] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 430

[Voyage en Italie : 1824-1830]. , [Détails de peintures décoratives] : [un motif de char tiré par des lionnes] : [dessin] / [Henri Labrouste]

Référence bibliographique : Weigert, 436

[Voyage en Italie : 1824-1830]. , [Affiche électorale peinte sur un mur] : [un motif] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 463

Peroxisome proliferator-activated receptor mediates cross-talk with thyroid hormone receptor by competition for retinoid X receptor. Possible role of a leucine zipper-like heptad repeat.

The peroxisome proliferator-activated receptors (PPAR) and thyroid hormone receptors (TR) are members of the nuclear receptor superfamily, which regulate lipid metabolism and tissue differentiation. In order to bind to DNA and activate transcription, PPAR requires the formation of heterodimers with the retinoid X receptor (RXR). In addition to activating transcription through its own response elements, PPAR is able to selectively down-regulate the transcriptional activity of TR, but not vitamin D receptor. The molecular basis of this functional interaction has not been fully elucidated. By means of site-directed mutagenesis of hPPAR alpha we mapped its inhibitory action on TR to a leucine zipper-like motif in the ligand binding domain of PPAR, which is highly conserved among all subtypes of this receptor and mediates heterodimerization with RXR. Replacement of a single leucine by arginine at position 433 of hPPAR alpha (L433R) abolished heterodimerization of PPAR with RXR and consequently its trans-activating capacity. However, a similar mutation of a leucine residue to arginine at position 422 showed no alteration of heterodimerization, DNA binding, or transcriptional activation. The dimerization deficient mutant L433R was no longer able to inhibit TR action, demonstrating that the selective inhibitory effect of PPAR results from the competition for RXR as well as possibly for other TR-auxiliary proteins. In contrast, abolition of DNA binding by a mutation in the P-box of PPAR (C122S) did not eliminate the inhibition of TR trans-activation, indicating that competition for DNA binding is not involved. Additionally, no evidence for the formation of PPAR:TR heterodimers was found in co-immunoprecipitation experiments. In summary, we have demonstrated that PPAR selectively inhibits the transcriptional activity of TRs by competition for RXR and possibly non-RXR TR-auxiliary proteins. In contrast, this functional interaction is independent of the formation of PPAR:TR heterodimers or competition for DNA binding.