RESUMEN
RATIONALE: Insight into the function of nuclear factor (NF)-kappaB in the adult heart has been hampered by the embryonic lethality of constitutive NF-kappaB inactivation. OBJECTIVE: The goal of the present study was therefore to gain insights into the role of NF-kappaB pathway specifically in mouse cardiomyocytes by conditional deletion of the NF-kappaB essential modulator (NEMO). METHODS AND RESULTS: Using a Cre/loxP system, we disrupted the Nemo gene in a cardiomyocyte-specific manner in the heart, which simulated gene expression changes underlying human heart failure and caused adult-onset dilated cardiomyopathy accompanied by inflammation and apoptosis. Pressure overload challenges of NEMO-deficient young hearts precociously induced the functional decrements that develop spontaneously in older knockout animals. Moreover, oxidative stress in NEMO-deficient cardiomyocytes is a critical pathological component that can be attenuated with antioxidant diet in vivo. CONCLUSIONS: These results reveal an essential physiological role for NEMO-mediated signaling in the adult heart to maintain cardiac function in response to age-related or mechanical challenges, in part through modulation of oxidative stress.
Asunto(s)
Antioxidantes/metabolismo , Cardiomiopatía Dilatada/metabolismo , Quinasa I-kappa B/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Miocitos Cardíacos/metabolismo , Estrés Oxidativo , Transducción de Señal , Animales , Cardiomiopatía Dilatada/genética , Células Cultivadas , Eliminación de Gen , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/metabolismo , Humanos , Quinasa I-kappa B/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Masculino , Ratones , FN-kappa B/genética , FN-kappa B/metabolismoRESUMEN
We present the sequence of a contiguous 2.63 Mb of DNA extending from the tip of the X chromosome of Drosophila melanogaster. Within this sequence, we predict 277 protein coding genes, of which 94 had been sequenced already in the course of studying the biology of their gene products, and examples of 12 different transposable elements. We show that an interval between bands 3A2 and 3C2, believed in the 1970s to show a correlation between the number of bands on the polytene chromosomes and the 20 genes identified by conventional genetics, is predicted to contain 45 genes from its DNA sequence. We have determined the insertion sites of P-elements from 111 mutant lines, about half of which are in a position likely to affect the expression of novel predicted genes, thus representing a resource for subsequent functional genomic analysis. We compare the European Drosophila Genome Project sequence with the corresponding part of the independently assembled and annotated Joint Sequence determined through "shotgun" sequencing. Discounting differences in the distribution of known transposable elements between the strains sequenced in the two projects, we detected three major sequence differences, two of which are probably explained by errors in assembly; the origin of the third major difference is unclear. In addition there are eight sequence gaps within the Joint Sequence. At least six of these eight gaps are likely to be sites of transposable elements; the other two are complex. Of the 275 genes in common to both projects, 60% are identical within 1% of their predicted amino-acid sequence and 31% show minor differences such as in choice of translation initiation or termination codons; the remaining 9% show major differences in interpretation.
Asunto(s)
Proteínas de Drosophila , Drosophila melanogaster/genética , Genes de Insecto/genética , Análisis de Secuencia de ADN/métodos , Cromosoma X/genética , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Biología Computacional , Elementos Transponibles de ADN/genética , Proteínas de Unión al ADN/genética , Femenino , Orden Génico/genética , Masculino , Datos de Secuencia Molecular , Mapeo Físico de Cromosoma/métodos , Factores de Transcripción/genéticaRESUMEN
One of the rewards of having a Drosophila melanogaster whole-genome sequence will be the potential to understand the molecular bases for structural features of chromosomes that have been a long-standing puzzle. Analysis of 2.6 megabases of sequence from the tip of the X chromosome of Drosophila identifies 273 genes. Cloned DNAs from the characteristic bulbous structure at the tip of the X chromosome in the region of the broad complex display an unusual pattern of in situ hybridization. Sequence analysis revealed that this region comprises 154 kilobases of DNA flanked by 1.2-kilobases of inverted repeats, each composed of a 350-base pair satellite related element. Thus, some aspects of chromosome structure appear to be revealed directly within the DNA sequence itself.