RESUMEN
The SAGA coactivator complex is essential for eukaryotic transcription and comprises four distinct modules, one of which contains the ubiquitin hydrolase USP22. In yeast, the USP22 ortholog deubiquitylates H2B, resulting in Pol II Ser2 phosphorylation and subsequent transcriptional elongation. In contrast to this H2B-associated role in transcription, we report here that human USP22 contributes to the early stages of stimulus-responsive transcription, where USP22 is required for pre-initiation complex (PIC) stability. Specifically, USP22 maintains long-range enhancer-promoter contacts and controls loading of Mediator tail and general transcription factors (GTFs) onto promoters, with Mediator core recruitment being USP22-independent. In addition, we identify Mediator tail subunits MED16 and MED24 and the Pol II subunit RBP1 as potential non-histone substrates of USP22. Overall, these findings define a role for human SAGA within the earliest steps of transcription.
Asunto(s)
Ubiquitina Tiolesterasa/genética , Apoptosis , Estrés del Retículo Endoplásmico/genética , Células HCT116 , Humanos , Complejo Mediador/genética , Regiones Promotoras Genéticas , ARN Polimerasa II , Transcripción GenéticaRESUMEN
A series of benzo[h][1,6]naphthyridine and azepino[3,2-c]quinoline derivatives were prepared and evaluated to determine the necessary requirements for high affinity on the 5-HT(4) receptors and high selectivity versus other receptors. The compounds were synthesized by substituting the chlorine atom of benzonaphthyridines and azepinoquinolines with various N-alkyl-4-piperidinylmethanolates. They were evaluated in binding assays with [(3)H]GR 113808 as the 5-HT(4) receptor radioligand. The affinity values (K(i) or inhibition percentages) depended upon the substituent on the aromatic ring on one hand and the substituent on the lateral piperidine chain on the other hand. A chlorine atom produced a marked drop in activity while a N-propyl or N-butyl group gave compounds with nanomolar affinities (1 < K(i) < 10 nM). Among the most potent ligands (3a, 4a, 5a), 4a was selected on the basis of its high affinity and selectivity for pharmacological screening and was evaluated in vivo in specific tests. This compound reveals itself as an antagonist/low partial agonist in the COS-7 cells stably expressing the 5-HT(4(a)) receptor. Derivative 4a also showed in vivo potent analgesic activity in the writhing test at very low doses.
Asunto(s)
Naftiridinas/síntesis química , Quinolinas/síntesis química , Receptores de Serotonina/efectos de los fármacos , Antagonistas de la Serotonina/síntesis química , Animales , Conducta Animal/efectos de los fármacos , Células COS , Chlorocebus aethiops , AMP Cíclico/biosíntesis , Cobayas , Dosificación Letal Mediana , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Ratones , Naftiridinas/química , Naftiridinas/farmacología , Quinolinas/química , Quinolinas/farmacología , Ensayo de Unión Radioligante , Receptores de Serotonina/metabolismo , Receptores de Serotonina 5-HT4 , Antagonistas de la Serotonina/química , Antagonistas de la Serotonina/farmacología , Agonistas de Receptores de Serotonina/síntesis química , Agonistas de Receptores de Serotonina/química , Agonistas de Receptores de Serotonina/farmacología , Relación Estructura-Actividad , Pruebas de Toxicidad AgudaRESUMEN
A series of N-omega-aminoalkyl- or N-omega-amidinoalkyl-2,4,6-triisopropyl benzenesulfonamides has been synthesized and their respective affinity indices on 5-HT6 receptor determined. This evaluation clearly showed that the compounds possessing an arylpiperazine moiety or an amidine function exhibited good affinity for the model.