RESUMEN
The aim of the present study was to evaluate the relationship between the matrix degradation biomarkers, desmosine and isodesmosine (desmosines), and lung function. Plasma and creatinine-corrected urinary total desmosines (P- and U-desmosines, respectively), lung function and diffusing capacity of the lung for carbon monoxide (D(L,CO)) were measured in a cohort of subjects from the Swedish Twin Registry. Concentrations of U- and P-desmosines were measured in 349 and 318 subjects, respectively; approximately one-third of subjects had chronic obstructive pulmonary disease (COPD). Age, female sex, body mass index (BMI) and smoking were significantly associated with U-desmosines in a multiple linear regression analysis. In the overall population, after adjustments for age, sex, height, BMI and smoking, concentrations of U-desmosines were significantly correlated with all lung function measures, and P-desmosines with forced expiratory volume in 1 s and D(L,CO) (p<0.05). With the exception of residual volume versus P-desmosines, relationships between concentrations of desmosines and lung function measures were markedly stronger in subjects with COPD compared with those without COPD. These cross-sectional data showing associations between desmosines and several lung function variables suggest that desmosines, particularly U-desmosines, could be a useful biomarker of COPD status.
Asunto(s)
Desmosina/orina , Isodesmosina/orina , Pulmón/fisiología , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Enfermedad Pulmonar Obstructiva Crónica/orina , Anciano , Anciano de 80 o más Años , Biomarcadores/sangre , Biomarcadores/orina , Desmosina/sangre , Femenino , Humanos , Isodesmosina/sangre , Masculino , Persona de Mediana Edad , Enfermedad Pulmonar Obstructiva Crónica/sangre , Sistema de Registros , Pruebas de Función Respiratoria , Sensibilidad y Especificidad , Fumar/sangre , Fumar/orinaRESUMEN
The mammalian 1-Cys peroxiredoxin (Prdx6) is a unique member of the peroxiredoxin family of proteins capable of protecting cells from metal-catalyzed oxidative damage. We recently identified Prdx6 as a candidate for the quantitative trait locus Ath1, a gene responsible for a difference in diet-induced atherosclerosis susceptibility in mice. To investigate the role of Prdx6 in atherosclerosis, we generated transgenic mice that overexpress the Prdx6 allele from the Ath1-resistant 129/SvJ strain on an Ath1-susceptible C57BL/6J background. These mice expressed significantly elevated levels of Prdx6 mRNA and protein in multiple tissues including liver, aorta, and peritoneal macrophages, which accumulated significantly lower levels of hydrogen peroxide, revealing an enhanced antioxidant activity in these mice. However, overexpression of Prdx6 had no protective effect on LDL oxidation in vitro, and transgenic mice fed an atherogenic diet for 10 weeks did not possess an increased resistance to atherosclerosis nor did they maintain the high prediet plasma HDL levels consistent with the Ath1-resistant phenotype. In addition, the Prdx6 allele from the susceptible strain was shown to have a higher antioxidant activity than that of the resistant strains. These data suggest that the increased peroxidase activity attributable to Prdx6 overexpression in transgenic mice is not sufficient to protect mice from atherosclerosis, and that Prdx6 is not likely to be the gene underlying Ath1.
Asunto(s)
Aorta/metabolismo , Arteriosclerosis/inducido químicamente , Arteriosclerosis/metabolismo , Dieta , Peróxido de Hidrógeno/metabolismo , Peroxidasas/genética , Peroxidasas/metabolismo , Alelos , Animales , Aorta/anatomía & histología , Arteriosclerosis/genética , Arteriosclerosis/patología , HDL-Colesterol/metabolismo , LDL-Colesterol/metabolismo , Glutamato-Amoníaco Ligasa/metabolismo , Peroxidación de Lípido , Hígado/metabolismo , Macrófagos Peritoneales , Ratones , Ratones Transgénicos , Peroxiredoxina VI , Peroxirredoxinas , Transgenes/genéticaRESUMEN
Migraine is the most common type of chronic episodic headache. To find novel susceptibility genes for familial migraine with and without aura, a genomewide screen was performed in a large family from northern Sweden. Evidence of linkage was obtained on chromosome 6p12.2-p21.1, with a maximum two-point lod score of 5.41 for marker D6S452. The patients with migraine shared a common haplotype of 10 Mb between markers D6S1650 and D6S1960.
Asunto(s)
Cromosomas Humanos Par 6/genética , Migraña con Aura/genética , Migraña sin Aura/genética , Adulto , ADN/genética , Femenino , Ligamiento Genético/genética , Marcadores Genéticos , Haplotipos , Humanos , Escala de Lod , Masculino , Persona de Mediana Edad , Migraña con Aura/fisiopatología , Migraña sin Aura/fisiopatología , Linaje , SueciaRESUMEN
A gene encoding the enamel protein ameloblastin (AMBN) was recently localized to a region on chromosome 4q21 containing a gene for the inherited enamel defect local hypoplastic amelogenesis imperfecta (AIH2). Ameloblastin protein is located at the Tomes processes of secretory ameloblasts and in the sheath space between rod-interrod enamel, and the AMBN gene therefore represents a viable candidate gene for local hypoplastic amelogenesis imperfecta (AI). In this study, the genomic organization of human AMBN was characterized. The gene was shown to consist of 13 exons and 12 introns. An alternatively spliced 45 bp sequence was shown not to represent a separate exon and is most likely spliced by the use of a cryptic splice site. The finding that there were no recombinations between an intragenic microsatellite and AIH2 encouraged us to evaluate this gene's potential role as a candidate gene for local hypoplastic AI. Mutation screening was performed on all 13 exons in 20 families and 8 sporadic cases with 6 different forms of AI. DNA variants were found but none that was associated exclusively with local hypoplastic AI or any of the other variants of AI in the identified Swedish families. This study excludes the coding regions and the splice sites of AMBN from a causative role in the pathogenesis of AIH2.
Asunto(s)
Amelogénesis Imperfecta/genética , Proteínas del Esmalte Dental/genética , Cromosomas Humanos Par 4 , Análisis Mutacional de ADN , Exones , Humanos , Intrones , Repeticiones de Microsatélite , Polimorfismo Conformacional Retorcido-SimpleRESUMEN
Enamelin is likely to be essential for proper dental enamel formation. It is secreted by ameloblasts throughout the secretory stage and can readily be isolated from the enamel matrix of developing teeth. The gene encoding human enamelin is located on the long arm of chromosome 4, in a region previously linked to an autosomal-dominant form of amelogenesis imperfecta (AI). To gain information on the structure of the enamelin gene and to facilitate the future assessment of the role of enamelin in normal and diseased enamel formation, we have cloned and characterized the mouse and human enamelin genes. Both genes are about 25 kilobases long. The enamelin gene has 10 exons interrupted by 9 introns. Translation initiates in exon 3 and terminates in exon 10. All of the intron/exon junctions within the mouse and human enamelin coding regions are between codons, so there are no partial codons in any exon, and deletion of one or more coding exons by alternative RNA splicing would not shift the downstream reading frame.
Asunto(s)
Proteínas del Esmalte Dental/genética , Ameloblastos/metabolismo , Amelogénesis/genética , Amelogénesis Imperfecta/genética , Animales , Composición de Base , Cromosomas Humanos Par 4/genética , Clonación de Organismos , Codón/genética , Órgano del Esmalte/metabolismo , Exones/genética , Eliminación de Gen , Humanos , Intrones/genética , Ratones , Datos de Secuencia Molecular , Sistemas de Lectura/genética , Análisis de Secuencia de ADN , Germen Dentario/metabolismoRESUMEN
OBJECTIVE: To describe the phenotype of Bothnia dystrophy, an autosomal recessive retinal dystrophy with an R234W mutation in the RLBP1 gene encoding cellular retinaldehyde-binding protein. DESIGN: Medical records were reviewed retrospectively. Ophthalmologic examination, including kinetic perimetry and, in selected cases, adaptometry, color vision tests, fluorescein angiography, and electrophysiologic studies, was performed. The study included 24 individuals, all homozygous for an R234W mutation in the RLBP1 gene. RESULTS: Patients typically show night blindness from early childhood. In young adults, retinitis punctata albescens was observed, followed by macular degeneration and a decrease in visual acuity that led to legal blindness in early adulthood. Dark adaptometry and electrophysiologic testing showed an initial loss of rod function followed by a progressive reduction of the cone responses in older ages. CONCLUSIONS: Bothnia dystrophy is a unique retinal dystrophy belonging to the rod-cone dystrophies and has a high prevalence in northern Sweden. Fifty-seven cases of Bothnia dystrophy have been diagnosed, indicating a prevalence as high as 1 per 4500 population in the geographic area studied. A defect ability of mutated cellular retinaldehyde-binding protein to bind retinoid probably explains the defect rod function followed by central and peripheral degeneration. CLINICAL RELEVANCE: Retinal dystrophies associated with other mutations of the RLBP1 gene, including retinitis pigmentosa of Bothnia type, might account for a considerable number of cases of autosomal recessive retinitis pigmentosa in other geographic areas as well.
Asunto(s)
Proteínas Portadoras/genética , Mutación Puntual , Retinaldehído/genética , Retinitis Pigmentosa/genética , Adolescente , Adulto , Anciano , Niño , Electrofisiología , Femenino , Angiografía con Fluoresceína , Humanos , Masculino , Persona de Mediana Edad , Fenotipo , Células Fotorreceptoras de Vertebrados/fisiología , Retinitis Pigmentosa/epidemiología , Retinitis Pigmentosa/fisiopatología , Estudios Retrospectivos , Suecia/epidemiología , Agudeza Visual , Campos VisualesAsunto(s)
Adhesinas de Escherichia coli/genética , Proteínas de Escherichia coli , Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica , Proteínas de la Membrana , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Secuencia de Bases , ADN Bacteriano/genética , Escherichia coli/patogenicidad , Humanos , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Factores de Transcripción/química , Infecciones Urinarias/microbiologíaRESUMEN
Amelogenesis imperfecta is a broad classification of hereditary enamel defects, exhibiting both genetic and clinical diversity. Most amelogenesis imperfecta cases are autosomal dominant disorders, yet only the local hypoplastic form has been mapped to human chromosome 4q between D4S242 1 and the albumin gene. An enamel protein cDNA, termed ameloblastin (also known as amelin and sheathlin), has been isolated from rat, mouse and pig. Its human homolog has been mapped to chromosome 4q21 between markers D4S409 and D4S400, flanking the local hypoplastic amelogenesis imperfecta critical region. Therefore, ameloblastin is a strong candidate gene for this form of amelogenesis imperfecta. To facilitate genetic studies related to this dental disease, we isolated and characterized a human ameloblastin cDNA. A human third molar cDNA library was screened and two ameloblastin clones identified. Nucleotide sequencing of these cDNAs indicated alternative splicing of the putative open reading frame, use of different polyadenylation signals, and a high degree of similarity to reported rat, mouse and porcine cDNAs. Immunohistochemistry studies on embryonic human teeth using an antibody to recombinant ameloblastin indicated ameloblastin expression by ameloblasts with localization in the enamel matrix associated with the sheath structures.
Asunto(s)
Amelogénesis Imperfecta/genética , Proteínas del Esmalte Dental/química , Proteínas del Esmalte Dental/genética , Empalme Alternativo , Ameloblastos , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Cromosomas Humanos Par 4 , Clonación Molecular , Humanos , Técnicas para Inmunoenzimas , Ratones , Datos de Secuencia Molecular , Peso Molecular , Ratas , Análisis de Secuencia de ADN , PorcinosRESUMEN
Pathogenic Escherichia coli often carry determinants for several different adhesins. We show a direct communication between two adhesin gene clusters in uropathogenic E.coli: type 1 fimbriae (fim) and pyelonephritis-associated pili (pap). A regulator of pap, PapB, is a key factor in this cross-talk. FimB recombinase turns on type 1 fimbrial expression, and PapB inhibited phase transition by FimB in both off-to-on and on-to-off directions. On-to-off switching requiring FimE was increased by PapB. By analysis of FimB- and FimE-LacZ translational fusions it was concluded that the increase in on-to-off transition rates was via an increase in FimE expression. Inhibition of FimB-promoted switching was via a different mechanism: PapB inhibited FimB-promoted in vitro recombination, indicating that FimB activity was blocked at the fim switch. In vitro analyses showed that PapB bound to several DNA regions of the type 1 fimbrial operon, including the fim switch region. These data show that Pap expression turns off type 1 fimbriae expression in the same cell. Such cross-talk between adhesin gene clusters may bring about appropriate expression at the single cell level.
Asunto(s)
Adhesinas de Escherichia coli/genética , Proteínas Bacterianas/genética , Proteínas de Unión al ADN/genética , Proteínas de Escherichia coli , Escherichia coli/genética , Integrasas , Proteínas de la Membrana , Pili Sexual/genética , Factores de Transcripción/genética , Secuencia de Bases , Cartilla de ADN/genética , ADN Bacteriano/genética , ADN Bacteriano/metabolismo , Escherichia coli/patogenicidad , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Genes de Cambio , Humanos , Familia de Multigenes , Operón , Regiones Promotoras Genéticas , Recombinación GenéticaRESUMEN
We present the clinical and molecular genetic features of a large multi-generation Norwegian family with dominant cone-rod dystrophy. Ophthalmological evaluation including electroretinography showed cone dysfunction in younger patients, with rod dysfunction becoming apparent at more advanced stages of the disease. In one branch of the family, cone degeneration remained the only manifestation despite advancing age. Linkage analysis mapped the disease gene in this family to 17p12-p13, a chromosome region previously linked to cone-rod dystrophy in a Swedish family (CORD5). A maximum LOD score of 3.25 (straight theta = 0.00) for marker D17S1844 was obtained. Mutation analysis of the guanylate cyclase 2D gene (GUCY2D, MIM 600179, previously called RETGC1), located at 17p12-p13, showed a missense mutation (R838C) in exon 13, that co-segregated with the eye disease in the family. Our suspicion of the possibility of an interrelationship between the Swedish CORD5 family and the present family, both originating from Northern Scandinavia, initiated the linkage analysis in the Norwegian family. The R838C missense mutation was not, however, detected in the Swedish patients, strongly suggesting no relationship between these two families. The long-term ophthalmological evaluation in this large four-generation family, combined with the identification of the disease-causing mutation, provide critical information for refining the classification, prognosis, and genetic counselling of patients with cone-rod dystrophies.
Asunto(s)
Guanilato Ciclasa/genética , Mutación Missense , Células Fotorreceptoras de Vertebrados/patología , Degeneración Retiniana/genética , Adulto , Anciano , Niño , Cromosomas Humanos Par 17/genética , Defectos de la Visión Cromática/genética , Defectos de la Visión Cromática/fisiopatología , Análisis Mutacional de ADN , Electrorretinografía , Femenino , Genes Dominantes , Ligamiento Genético , Humanos , Escala de Lod , Masculino , Persona de Mediana Edad , Linaje , Células Fotorreceptoras de Vertebrados/enzimología , Reacción en Cadena de la Polimerasa , Degeneración Retiniana/enzimología , Degeneración Retiniana/fisiopatología , Células Fotorreceptoras Retinianas Bastones/enzimología , Células Fotorreceptoras Retinianas Bastones/fisiología , Agudeza Visual , Campos VisualesRESUMEN
We have determined the exon-intron organization and characterized the 5'-flanking promoter region of DLG4. Encompassing approximately 30 kb, the DLG4 locus is composed of 22 exons that range in size from 28 to 1,218 nucleotides. All splice sites conform to the GT-AG rule, except for the splice acceptor site of intron 5, which is TG instead of AG. Three different exons of DLG4 were found to be alternatively spliced in a subset of tissues. Two of these variants result in altered postsynaptic density 95 (PSD95) isoforms that dramatically truncate the protein. The third splicing variant represents an extension of exon 4 that encodes an additional 33-amino acid segment. Analysis of the core promoter region for DLG4 suggests that the expression of this gene is controlled by a TATA-less promoter using a single transcriptional start site embedded within a CpG island. DLG4 maps to a region on chromosome 17p13.1 known to contain a locus for autosomal dominant cone dystrophy 5. Scanning for mutations in the DLG4 coding region and splice sites was performed in 15 cone dystrophy patients, including probands from five families showing linkage to the DLG4 region. No disease-causing mutations were identified in any patients, suggesting that DLG4 is not the causative gene for this genetic eye disorder.
Asunto(s)
Cromosomas Humanos Par 17/genética , Enfermedades Hereditarias del Ojo/genética , Genes , Proteínas del Tejido Nervioso/genética , Enfermedades de la Retina/genética , Secuencia de Aminoácidos , Secuencia de Bases , Química Encefálica , Islas de CpG , Análisis Mutacional de ADN , ADN Complementario/genética , Homólogo 4 de la Proteína Discs Large , Exones/genética , Genes Dominantes , Ligamiento Genético , Pruebas Genéticas , Humanos , Péptidos y Proteínas de Señalización Intracelular , Intrones/genética , Masculino , Proteínas de la Membrana , Datos de Secuencia Molecular , Polimorfismo de Longitud del Fragmento de Restricción , Polimorfismo Conformacional Retorcido-Simple , Regiones Promotoras Genéticas , Isoformas de Proteínas/genética , Empalme del ARN , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Suecia , Testículo/química , Transcripción Genética , Estados UnidosRESUMEN
PURPOSE: To determine the chromosomal location and to identify the gene causing a type of retinitis punctata albescens, called Bothnia dystrophy, found in a restricted geographic area in northern Sweden. METHODS: Twenty patients from seven families originating from a restricted geographic area in northern Sweden were clinically examined. Microsatellite markers were analyzed in all affected and unaffected family members. Direct genomic sequencing of the gene encoding cellular retinaldehyde-binding protein was performed after the linkage analysis had been completed. RESULTS: Affected individuals showed night blindness from early childhood with features consistent with retinitis punctata albescens and macular degeneration. The responsible gene was mapped to 15q26, the same region to which the cellular retinaldehyde-binding protein gene has been assigned. Subsequent analysis showed all affected patients were homozygous for a C to T substitution in exon 7 of the same gene, leading to the missense mutation Arg234Trp. Analysis of marker haplotypes suggested that all cases had a common ancestor who carried the mutation. CONCLUSIONS: A missense mutation in the cellular retinaldehyde-binding protein gene is the cause of Bothnia dystrophy. The disease is a local variant of retinitis punctata albescens that is common in northern Sweden due to a founder mutation.