RESUMEN
The Rbtg3 gene was isolated by PCR (polymerase chain reaction) cloning from the cDNA library of Rat1 fibroblasts that were stimulated with TPA (12-O-tetradecanoylphorbol-13-acetate) or various growth factors for 3h and was found to be a rat homologue of mouse BTG3 and human ANA genes. The Rbtg3 gene had unique DNA sequences in the 5'-UTR and 3'-UTR that contained four ATTTA and one TTATTTA(T/A)(T/A) nonamer motif, and also a polyA addition site. Nucleotide homology of Rbtg3 with BTG3 and ANA was 88.5 and 76.6%, respectively. Expression of Rbtg3 was investigated in SD rats as well as cell lines derived from mouse--SW3T3, NIH3T3 fibroblasts--and rat--Rat1, 3Y1 fibroblasts and PC12--cells. Rbtg3 was highly expressed in brain but barely in lung, kidney, thymus and spleen. The constitutive expression level was high in SW3T3, Rat1 and 3Y1 fibroblasts, but very low in NIH3T3 fibroblast and PC12 cells. However, in all cells tested, Rbtg3 was proved to be one of the primary response genes superinduced by TPA (50ng/ml)+cycloheximide (CHX, 10 microgram/ml). Expression of Rbtg3 was induced by H(2)O(2) (500mM) up to fourfold in PC12 cells and was blocked by pretreatment of NAC (N-acetyl-L-cysteine, 10mM). The induction was ninefold in 3Y1 fibroblasts by menadione (25mM) treatment for 1h, whereas it was reduced to a third of the control level in SW3T3 fibroblast by the same treatment. Rbtg3 was not expressed in NIH3T3 cells but minimally regulated by redox changes as compared with rapid and strong induction of TIS21/BTG2 mRNAs after TPA or H(2)O(2) stimulation. The above results indicate that Rbtg3 is one of many redox-regulated genes as well as a primary response gene.
Asunto(s)
Regulación de la Expresión Génica/genética , Genes Supresores de Tumor , Oxidación-Reducción , Proteínas/genética , Regiones no Traducidas 3' , Células 3T3 , Regiones no Traducidas 5' , Acetilcisteína/farmacología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Encéfalo/metabolismo , Línea Celular , Cicloheximida/farmacología , ADN Complementario/química , ADN Complementario/genética , Depuradores de Radicales Libres/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Peróxido de Hidrógeno/farmacología , Proteínas Inmediatas-Precoces/efectos de los fármacos , Proteínas Inmediatas-Precoces/genética , Proteínas Inmediatas-Precoces/metabolismo , Ratones , Datos de Secuencia Molecular , Células PC12 , ARN/genética , ARN/metabolismo , ARN Mensajero/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Acetato de Tetradecanoilforbol/farmacología , Proteínas Supresoras de TumorRESUMEN
A non-washout preparation using Picolax in 40 patients, compared with a standard method using washouts in 38 patients, showed no significant difference in the contamination by residual formed or semiliquid faeces, although Picolax was associated with significantly more contamination due to adherent faeces and mucus. The overall differences in contamination were most marked in the transverse colon. Picolax also affected the smooth muscle tone of the bowel wall, causing an increase in 'mucosal crinkling'.