RESUMEN
Children in rural communities consume more energy-dense foods relative to their urban peers. Identifying effective interventions for improving energy intake patterns are needed to address these geographic disparities. The primary aim of this study was to harness the benefits of physical activity on children's executive functioning to see if these improvements lead to acute changes in eating behaviors. In a randomized crossover design, 91 preadolescent (8-10y; M age = 9.48 ± 0.85; 50.5% female; 85.7% White, 9.9% Multiracial, 9.9% Hispanic) children (86% rural) completed a 20-minute physical activity condition (moderate intensity walking) and time-matched sedentary condition (reading and/or coloring) ~ 14 days apart. Immediately following each condition, participants completed a behavioral inhibition task and then eating behaviors (total energy intake, relative energy intake, snack intake) were measured during a multi-array buffet test meal. After adjusting for period and order effects, body fat (measured via DXA), and depressive symptoms, participants experienced significant small improvements in their behavioral inhibition following the physical activity versus sedentary condition (p = 0.04, Hedge's g = 0.198). Eating behaviors did not vary by condition, nor did improvements in behavioral inhibition function as a mediator (ps > 0.09). Thus, in preadolescent children, small improvements in behavioral inhibition from physical activity do not produce acute improvements in energy intake. Additional research is needed to clarify whether the duration and/or intensity of physical activity sessions would produce different results in this age group, and whether intervention approaches and corresponding mechanisms of change vary by individual factors, like age and degree of food cue responsivity.
Asunto(s)
Ingestión de Energía , Ejercicio Físico , Conducta Alimentaria , Inhibición Psicológica , Humanos , Femenino , Masculino , Niño , Conducta Alimentaria/psicología , Ejercicio Físico/psicología , Estudios Cruzados , Conducta Infantil/psicología , Función Ejecutiva , Conducta SedentariaRESUMEN
Long-read sequencing can overcome the weaknesses of short reads in the assembly of eukaryotic genomes; however, at present additional scaffolding is needed to achieve chromosome-level assemblies. We generated Pacific Biosciences (PacBio) long-read data of the genomes of three relatives of the model plant Arabidopsis thaliana and assembled all three genomes into only a few hundred contigs. To improve the contiguities of these assemblies, we generated BioNano Genomics optical mapping and Dovetail Genomics chromosome conformation capture data for genome scaffolding. Despite their technical differences, optical mapping and chromosome conformation capture performed similarly and doubled N50 values. After improving both integration methods, assembly contiguity reached chromosome-arm-levels. We rigorously assessed the quality of contigs and scaffolds using Illumina mate-pair libraries and genetic map information. This showed that PacBio assemblies have high sequence accuracy but can contain several misassemblies, which join unlinked regions of the genome. Most, but not all, of these misjoints were removed during the integration of the optical mapping and chromosome conformation capture data. Even though none of the centromeres were fully assembled, the scaffolds revealed large parts of some centromeric regions, even including some of the heterochromatic regions, which are not present in gold standard reference sequences.
Asunto(s)
Cromosomas de las Plantas/química , Mapeo Contig/métodos , Genoma de Planta , Genómica/métodos , Programas Informáticos , Arabidopsis/genética , Cromosomas de las Plantas/genética , Mapeo Contig/normas , Genómica/normasRESUMEN
Uncombable hair syndrome (UHS), also known as "spun glass hair syndrome," "pili trianguli et canaliculi," or "cheveux incoiffables" is a rare anomaly of the hair shaft that occurs in children and improves with age. UHS is characterized by dry, frizzy, spangly, and often fair hair that is resistant to being combed flat. Until now, both simplex and familial UHS-affected case subjects with autosomal-dominant as well as -recessive inheritance have been reported. However, none of these case subjects were linked to a molecular genetic cause. Here, we report the identification of UHS-causative mutations located in the three genes PADI3 (peptidylarginine deiminase 3), TGM3 (transglutaminase 3), and TCHH (trichohyalin) in a total of 11 children. All of these individuals carry homozygous or compound heterozygous mutations in one of these three genes, indicating an autosomal-recessive inheritance pattern in the majority of UHS case subjects. The two enzymes PADI3 and TGM3, responsible for posttranslational protein modifications, and their target structural protein TCHH are all involved in hair shaft formation. Elucidation of the molecular outcomes of the disease-causing mutations by cell culture experiments and tridimensional protein models demonstrated clear differences in the structural organization and activity of mutant and wild-type proteins. Scanning electron microscopy observations revealed morphological alterations in hair coat of Padi3 knockout mice. All together, these findings elucidate the molecular genetic causes of UHS and shed light on its pathophysiology and hair physiology in general.
Asunto(s)
Antígenos/genética , Enfermedades del Cabello/genética , Cabello/crecimiento & desarrollo , Hidrolasas/genética , Proteínas de Filamentos Intermediarios/genética , Mutación , Transglutaminasas/genética , Adolescente , Animales , Secuencia de Bases , Línea Celular , Codón sin Sentido , Femenino , Cabello/anomalías , Cabello/anatomía & histología , Cabello/metabolismo , Humanos , Hidrolasas/deficiencia , Hidrolasas/metabolismo , Masculino , Ratones , Ratones Noqueados , Modelos Moleculares , Mutación Missense/genética , Conformación Proteica , Arginina Deiminasa Proteína-Tipo 3 , Desiminasas de la Arginina Proteica , Transglutaminasas/deficiencia , Transglutaminasas/metabolismo , Vibrisas/anomalíasRESUMEN
Single-case designs are a class of repeated measures experiments used to evaluate the effects of interventions for small or specialized populations, such as individuals with low-incidence disabilities. There has been growing interest in systematic reviews and syntheses of evidence from single-case designs, but there remains a need to further develop appropriate statistical models and effect sizes for data from the designs. We propose a novel model for single-case data that exhibit nonlinear time trends created by an intervention that produces gradual effects, which build up and dissipate over time. The model expresses a structural relationship between a pattern of treatment assignment and an outcome variable, making it appropriate for both treatment reversal and multiple baseline designs. It is formulated as a generalized linear model so that it can be applied to outcomes measured as frequency counts or proportions, both of which are commonly used in single-case research, while providing readily interpretable effect size estimates such as log response ratios or log odds ratios. We demonstrate the gradual effects model by applying it to data from a single-case study and examine the performance of proposed estimation methods in a Monte Carlo simulation of frequency count data.
Asunto(s)
Modelos Estadísticos , Simulación por Computador , Interpretación Estadística de Datos , Humanos , Metaanálisis como Asunto , Método de Montecarlo , Dinámicas no LinealesRESUMEN
BACKGROUND: In February 2016, a new fungal disease was spotted in wheat fields across eight districts in Bangladesh. The epidemic spread to an estimated 15,000 hectares, about 16 % of the cultivated wheat area in Bangladesh, with yield losses reaching up to 100 %. Within weeks of the onset of the epidemic, we performed transcriptome sequencing of symptomatic leaf samples collected directly from Bangladeshi fields. RESULTS: Reinoculation of seedlings with strains isolated from infected wheat grains showed wheat blast symptoms on leaves of wheat but not rice. Our phylogenomic and population genomic analyses revealed that the wheat blast outbreak in Bangladesh was most likely caused by a wheat-infecting South American lineage of the blast fungus Magnaporthe oryzae. CONCLUSION: Our findings suggest that genomic surveillance can be rapidly applied to monitor plant disease outbreaks and provide valuable information regarding the identity and origin of the infectious agent.
Asunto(s)
Magnaporthe/patogenicidad , Enfermedades de las Plantas/microbiología , Triticum/microbiología , Bangladesh , Regulación de la Expresión Génica de las Plantas , Enfermedades de las Plantas/genética , Triticum/genéticaRESUMEN
Deafblindness is part of several genetic disorders. We investigated a consanguineous Egyptian family with two siblings affected by congenital hearing loss and retinal degeneration, initially diagnosed as Usher syndrome type 1. At teenage, severe enamel dysplasia, developmental delay, and microcephaly became apparent. Genome-wide homozygosity mapping and whole-exome sequencing detected a homozygous missense mutation, c.1238G>T (p.Gly413Val), affecting a highly conserved residue of peroxisomal biogenesis factor 6, PEX6. Biochemical profiling of the siblings revealed abnormal and borderline plasma phytanic acid concentration, and cerebral imaging revealed white matter disease in both. We show that Pex6 localizes to the apical extensions of secretory ameloblasts and differentiated odontoblasts at early stages of dentin synthesis in mice, and to cilia of retinal photoreceptor cells. We propose PEX6, and possibly other peroxisomal genes, as candidate for the rare cooccurrence of deafblindness and enamel dysplasia. Our study for the first time links peroxisome biogenesis disorders to retinal ciliopathies.
Asunto(s)
Adenosina Trifosfatasas/genética , Trastornos Sordoceguera/genética , Hipoplasia del Esmalte Dental/genética , Microcefalia/genética , Mutación Missense , Degeneración Retiniana/genética , ATPasas Asociadas con Actividades Celulares Diversas , Adenosina Trifosfatasas/metabolismo , Ameloblastos/metabolismo , Ameloblastos/patología , Secuencia de Aminoácidos , Animales , Niño , Cilios/metabolismo , Cilios/patología , Consanguinidad , Trastornos Sordoceguera/metabolismo , Trastornos Sordoceguera/patología , Hipoplasia del Esmalte Dental/metabolismo , Hipoplasia del Esmalte Dental/patología , Femenino , Expresión Génica , Homocigoto , Humanos , Masculino , Ratones , Microcefalia/metabolismo , Microcefalia/patología , Datos de Secuencia Molecular , Odontoblastos/metabolismo , Odontoblastos/patología , Linaje , Células Fotorreceptoras de Vertebrados/metabolismo , Células Fotorreceptoras de Vertebrados/patología , Degeneración Retiniana/metabolismo , Degeneración Retiniana/patología , Hermanos , Sustancia Blanca/metabolismo , Sustancia Blanca/patología , Adulto JovenRESUMEN
BACKGROUND: Melanotic neuroectodermal tumor of infancy (MNTI) is exceptionally rare and occurs predominantly in the head and neck (92.8 % cases). The patient reported here is only the eighth case of MNTI presenting in an extremity, and the first reported in the fibula. CASE PRESENTATION: A 2-month-old female presented with a mass arising in the fibula. Exhaustive genomic, transcriptomic, epigenetic and pathological characterization was performed on the excised primary tumor and a derived cell line. Whole-exome analysis of genomic DNA from both the tumor and blood indicated no somatic, non-synonymous coding mutations within the tumor, but a heterozygous, unique germline, loss of function mutation in CDKN2A (p16(INK4A), D74A). SNP-array CGH on DNA samples revealed the tumor to be euploid, with no detectable gene copy number variants. Multiple chromosomal translocations were identified by RNA-Seq, and fusion genes included RPLP1-C19MC, potentially deregulating the C19MC cluster, an imprinted locus containing microRNA genes reactivated by gene fusion in embryonal tumors with multilayered rosettes. Since the presumed cell of origin of MNTI is from the neural crest, we also compared gene expression with a dataset from human neural crest cells and identified 185 genes with significantly different expression. Consistent with the melanotic phenotype of the tumor, elevated expression of tyrosinase was observed. Other highly expressed genes encoded muscle proteins and modulators of the extracellular matrix. A derived MNTI cell line was sensitive to inhibitors of lysine demethylase, but not to compounds targeting other epigenetic regulators. CONCLUSIONS: In the absence of somatic copy number variations or mutations, the fully transformed phenotype of the MNTI may have arisen in infancy because of the combined effects of a germline CDKN2A mutation, tumor promoting somatic fusion genes and epigenetic deregulation. Very little is known about the etiology of MNTI and this report advances knowledge of these rare tumors by providing the first comprehensive genomic, transcriptomic and epigenetic characterization of a case.
Asunto(s)
Neoplasias Óseas/genética , Inhibidor p18 de las Quinasas Dependientes de la Ciclina/genética , Peroné/patología , Mutación de Línea Germinal , Tumor Neuroectodérmico Melanótico/genética , Proteínas de Fusión Oncogénica/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Lactante , Fosfoproteínas/genética , Proteínas Ribosómicas/genética , Análisis de Secuencia de ADN , Análisis de Secuencia de ARNRESUMEN
BACKGROUND: We describe the pioneering experience of a Spanish family pursuing the goal of understanding their own personal genetic data to the fullest possible extent using Direct to Consumer (DTC) tests. With full informed consent from the Corpas family, all genotype, exome and metagenome data from members of this family, are publicly available under a public domain Creative Commons 0 (CC0) license waiver. All scientists or companies analysing these data ("the Corpasome") were invited to return results to the family. METHODS: We released 5 genotypes, 4 exomes, 1 metagenome from the Corpas family via a blog and figshare under a public domain license, inviting scientists to join the crowdsourcing efforts to analyse the genomes in return for coauthorship or acknowldgement in derived papers. Resulting analysis data were compiled via social media and direct email. RESULTS: Here we present the results of our investigations, combining the crowdsourced contributions and our own efforts. Four companies offering annotations for genomic variants were applied to four family exomes: BIOBASE, Ingenuity, Diploid, and GeneTalk. Starting from a common VCF file and after selecting for significant results from company reports, we find no overlap among described annotations. We additionally report on a gut microbiome analysis of a member of the Corpas family. CONCLUSIONS: This study presents an analysis of a diverse set of tools and methods offered by four DTC companies. The striking discordance of the results mirrors previous findings with respect to DTC analysis of SNP chip data, and highlights the difficulties of using DTC data for preventive medical care. To our knowledge, the data and analysis results from our crowdsourced study represent the most comprehensive exome and analysis for a family quartet using solely DTC data generation to date.
Asunto(s)
Colaboración de las Masas , Familia , Pruebas Genéticas , Genómica , Colaboración de las Masas/métodos , Exoma , Femenino , Frecuencia de los Genes , Pruebas Genéticas/métodos , Genómica/métodos , Genotipo , Humanos , Masculino , Metagenoma , Linaje , Fenotipo , Polimorfismo de Nucleótido Simple , Medicina de Precisión/métodos , Carácter Cuantitativo Heredable , EspañaRESUMEN
Osteogenesis imperfecta (OI) is a clinically and genetically heterogeneous disorder associated with bone fragility and susceptibility to fractures after minimal trauma. OI type V has an autosomal-dominant pattern of inheritance and is not caused by mutations in the type I collagen genes COL1A1 and COL1A2. The most remarkable and pathognomonic feature, observed in ~65% of affected individuals, is a predisposition to develop hyperplastic callus after fractures or surgical interventions. To identify the molecular cause of OI type V, we performed whole-exome sequencing in a female with OI type V and her unaffected parents and searched for de novo mutations. We found a heterozygous de novo mutation in the 5'-untranslated region of IFITM5 (the gene encoding Interferon induced transmembrane protein 5), 14 bp upstream of the annotated translation initiation codon (c.-14C>T). Subsequently, we identified an identical heterozygous de novo mutation in a second individual with OI type V by Sanger sequencing, thereby confirming that this is the causal mutation for the phenotype. IFITM5 is a protein that is highly enriched in osteoblasts and has a putative function in bone formation and osteoblast maturation. The mutation c.-14C>T introduces an upstream start codon that is in frame with the reference open-reading frame of IFITM5 and is embedded into a stronger Kozak consensus sequence for translation initiation than the annotated start codon. In vitro, eukaryotic cells were able to recognize this start codon, and they used it instead of the reference translation initiation signal. This suggests that five amino acids (Met-Ala-Leu-Glu-Pro) are added to the N terminus and alter IFITM5 function in individuals with the mutation.
Asunto(s)
Proteínas de la Membrana/genética , Osteogénesis Imperfecta/genética , Regiones no Traducidas 5'/genética , Absorciometría de Fotón , Secuencia de Aminoácidos , Secuencia de Bases , Niño , Codón Iniciador/genética , Biología Computacional , Difosfonatos/uso terapéutico , Exoma/genética , Femenino , Humanos , Lactante , Datos de Secuencia Molecular , Osteogénesis Imperfecta/diagnóstico por imagen , Osteogénesis Imperfecta/tratamiento farmacológico , Mutación Puntual/genética , Análisis de Secuencia de ADNRESUMEN
Partial interval recording (PIR) is a procedure for collecting measurements during direct observation of behavior. It is used in several areas of educational and psychological research, particularly in connection with single-case research. Measurements collected using partial interval recording suffer from construct invalidity because they are not readily interpretable in terms of the underlying characteristics of the behavior. Using an alternating renewal process model for the behavior under observation, we demonstrate that ignoring the construct invalidity of PIR data can produce misleading inferences, such as inferring that an intervention reduces the prevalence of an undesirable behavior when in fact it has the opposite effect. We then propose four different methods for analyzing PIR summary measurements, each of which can be used to draw inferences about interpretable behavioral parameters. We demonstrate the methods by applying them to data from two single-case studies of problem behavior.
Asunto(s)
Investigación Conductal , Modelos Estadísticos , Simulación por Computador , Humanos , Factores de TiempoRESUMEN
The dynamics of reductive genome evolution for eukaryotes living inside other eukaryotic cells are poorly understood compared to well-studied model systems involving obligate intracellular bacteria. Here we present 8.5 Mb of sequence from the genome of the microsporidian Trachipleistophora hominis, isolated from an HIV/AIDS patient, which is an outgroup to the smaller compacted-genome species that primarily inform ideas of evolutionary mode for these enormously successful obligate intracellular parasites. Our data provide detailed information on the gene content, genome architecture and intergenic regions of a larger microsporidian genome, while comparative analyses allowed us to infer genomic features and metabolism of the common ancestor of the species investigated. Gene length reduction and massive loss of metabolic capacity in the common ancestor was accompanied by the evolution of novel microsporidian-specific protein families, whose conservation among microsporidians, against a background of reductive evolution, suggests they may have important functions in their parasitic lifestyle. The ancestor had already lost many metabolic pathways but retained glycolysis and the pentose phosphate pathway to provide cytosolic ATP and reduced coenzymes, and it had a minimal mitochondrion (mitosome) making Fe-S clusters but not ATP. It possessed bacterial-like nucleotide transport proteins as a key innovation for stealing host-generated ATP, the machinery for RNAi, key elements of the early secretory pathway, canonical eukaryotic as well as microsporidian-specific regulatory elements, a diversity of repetitive and transposable elements, and relatively low average gene density. Microsporidian genome evolution thus appears to have proceeded in at least two major steps: an ancestral remodelling of the proteome upon transition to intracellular parasitism that involved reduction but also selective expansion, followed by a secondary compaction of genome architecture in some, but not all, lineages.
Asunto(s)
Metabolismo Energético/genética , Genoma Fúngico , Microsporidios/genética , Proteoma/genética , Síndrome de Inmunodeficiencia Adquirida/microbiología , Evolución Biológica , Evolución Molecular , Humanos , Microsporidios/aislamiento & purificación , Mitocondrias , Filogenia , Proteómica , Interferencia de ARN , ARN Interferente Pequeño , Análisis de Secuencia de ADNAsunto(s)
Butirofilinas/genética , Proteínas de Unión al Calcio/genética , Colesteatoma del Oído Medio/genética , Familia de Proteínas EGF/genética , Secuenciación del Exoma/métodos , Predisposición Genética a la Enfermedad , Butirofilinas/metabolismo , Proteínas de Unión al Calcio/metabolismo , Colesteatoma del Oído Medio/fisiopatología , Familia de Proteínas EGF/metabolismo , Femenino , Humanos , Masculino , LinajeRESUMEN
Basaloid squamous cell carcinoma (BSCC) is a rare and aggressive variant of squamous cell carcinoma. It is commonly seen in the oropharynx and strongly associated with p16-expressivity and high-risk human papilloma virus (HPV). We report the first case of primary cutaneous p16-positive BSCC in an elderly woman, with a background of chronic inverse psoriasis of the natal cleft. P16-expressivity is a common surrogate marker for oncogenic HPV16, routinely tested for oropharyngeal/anogenital squamous cell carcinoma. This is not routinely done for primary cutaneous disease. Pilonidal disease is uncommon in the elderly population, and malignant transformation is rarer still. Surgical resection is considered the mainstay of treatment for primary cutaneous BSCC, however due to this patient's broad distribution of cutaneous field change and p16-expressivity, she was effectively treated with primary radiotherapy. This is a unique case of malignant transformation of pilonidal disease in an atypical demographic, with a rare/aggressive disease variant.
RESUMEN
MOTIVATION: Annotations are a key feature of many biological databases, used to convey our knowledge of a sequence to the reader. Ideally, annotations are curated manually, however manual curation is costly, time consuming and requires expert knowledge and training. Given these issues and the exponential increase of data, many databases implement automated annotation pipelines in an attempt to avoid un-annotated entries. Both manual and automated annotations vary in quality between databases and annotators, making assessment of annotation reliability problematic for users. The community lacks a generic measure for determining annotation quality and correctness, which we look at addressing within this article. Specifically we investigate word reuse within bulk textual annotations and relate this to Zipf's Principle of Least Effort. We use the UniProt Knowledgebase (UniProtKB) as a case study to demonstrate this approach since it allows us to compare annotation change, both over time and between automated and manually curated annotations. RESULTS: By applying power-law distributions to word reuse in annotation, we show clear trends in UniProtKB over time, which are consistent with existing studies of quality on free text English. Further, we show a clear distinction between manual and automated analysis and investigate cohorts of protein records as they mature. These results suggest that this approach holds distinct promise as a mechanism for judging annotation quality. AVAILABILITY: Source code is available at the authors website: http://homepages.cs.ncl.ac.uk/m.j.bell1/annotation. CONTACT: phillip.lord@newcastle.ac.uk.
Asunto(s)
Bases de Datos de Proteínas , Bases del Conocimiento , Anotación de Secuencia Molecular/normas , Proteínas/química , Proteínas/fisiologíaRESUMEN
There has been growing interest in using statistical methods to analyze data and estimate effect size indices from studies that use single-case designs (SCDs), as a complement to traditional visual inspection methods. The validity of a statistical method rests on whether its assumptions are plausible representations of the process by which the data were collected, yet there is evidence that some assumptions-particularly regarding normality of error distributions-may be inappropriate for single-case data. To develop more appropriate modeling assumptions and statistical methods, researchers must attend to the features of real SCD data. In this study, we examine several features of SCDs with behavioral outcome measures in order to inform development of statistical methods. Drawing on a corpus of over 300 studies, including approximately 1,800 cases, from seven systematic reviews that cover a range of interventions and outcome constructs, we report the distribution of study designs, distribution of outcome measurement procedures, and features of baseline outcome data distributions for the most common types of measurements used in single-case research. We discuss implications for the development of more realistic assumptions regarding outcome distributions in SCD studies, as well as the design of Monte Carlo simulation studies evaluating the performance of statistical analysis techniques for SCD data.
Asunto(s)
Evaluación de Resultado en la Atención de Salud , Proyectos de Investigación , Humanos , Simulación por Computador , Evaluación de Resultado en la Atención de Salud/métodosRESUMEN
OBJECTIVE: We sought clinically relevant predictive biomarkers present in CD4 T-cells, or in serum, that identified those patients with undifferentiated arthritis (UA) who subsequently develop rheumatoid arthritis (RA). METHODS: Total RNA was isolated from highly purified peripheral blood CD4 T cells of 173 early arthritis clinic patients. Paired serum samples were also stored. Microarray analysis of RNA samples was performed and differential transcript expression among 111 'training cohort' patients confirmed using real-time quantitative PCR. Machine learning approaches tested the utility of a classification model among an independent validation cohort presenting with UA (62 patients). Cytokine measurements were performed using a highly sensitive electrochemiluminescence detection system. RESULTS: A 12-gene transcriptional 'signature' identified RA patients in the training cohort and predicted the subsequent development of RA among UA patients in the validation cohort (sensitivity 68%, specificity 70%). STAT3-inducible genes were over-represented in the signature, particularly in anti-citrullinated peptide antibody-negative disease, providing a risk metric of similar predictive value to the Leiden score in seronegative UA (sensitivity 85%, specificity 75%). Baseline levels of serum interleukin 6 (IL-6) (which signals via STAT3) were highest in anti-citrullinated peptide antibodies-negative RA and distinguished this subgroup from non-RA inflammatory synovitis (corrected p<0.05).Paired serum IL-6 measurements correlated strongly with STAT3-inducible gene expression. CONCLUSION: The authors have identified IL-6-mediated STAT-3 signalling in CD4 T cells during the earliest clinical phase of RA, which is most prominent in seronegative disease. While highlighting potential biomarker(s) for early RA, the role of this pathway in disease pathogenesis awaits clarification.
Asunto(s)
Artritis Reumatoide/genética , Artritis Reumatoide/metabolismo , Biomarcadores/metabolismo , Linfocitos T CD4-Positivos/metabolismo , Interleucina-6/metabolismo , Factor de Transcripción STAT3/metabolismo , Adulto , Anciano , Artritis Reumatoide/diagnóstico , Autoanticuerpos/sangre , Linfocitos T CD4-Positivos/inmunología , Diagnóstico Precoz , Femenino , Humanos , Masculino , Persona de Mediana Edad , Péptidos Cíclicos/sangre , Péptidos Cíclicos/inmunología , Transducción de SeñalRESUMEN
Natural antisense transcripts (NATs) are important regulators of gene expression. Recently, a link between antisense transcription and the formation of endo-siRNAs has emerged. We investigated the bi-directionally transcribed Na/phosphate cotransporter gene (Slc34a1) under the aspect of endo-siRNA processing. Mouse Slc34a1 produces an antisense transcript that represents an alternative splice product of the Pfn3 gene located downstream of Slc34a1. The antisense transcript is prominently found in testis and in kidney. Co-expression of in vitro synthesized sense/antisense transcripts in Xenopus oocytes indicated processing of the overlapping transcripts into endo-siRNAs in the nucleus. Truncation experiments revealed that an overlap of at least 29 base-pairs is required to induce processing. We detected endo-siRNAs in mouse tissues that co express Slc34a1 sense/antisense transcripts by northern blotting. The orientation of endo-siRNAs was tissue specific in mouse kidney and testis. In kidney where the Na/phosphate cotransporter fulfils its physiological function endo-siRNAs complementary to the NAT were detected, in testis both orientations were found. Considering the wide spread expression of NATs and the gene silencing potential of endo-siRNAs we hypothesized a genome-wide link between antisense transcription and monoallelic expression. Significant correlation between random imprinting and antisense transcription could indeed be established. Our findings suggest a novel, more general role for NATs in gene regulation.
Asunto(s)
ARN Interferente Pequeño/metabolismo , Proteínas Cotransportadoras de Sodio-Fosfato de Tipo IIa/genética , Animales , Femenino , Riñón/metabolismo , Masculino , Ratones , Ratones Endogámicos BALB C , Oocitos/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/análisis , Testículo/metabolismo , Distribución Tisular , XenopusRESUMEN
Most human somatic cells contain no or very low levels of telomerase. The over-expression of the catalytic subunit (hTERT) of human telomerase is a common method to generate cells with a greatly prolonged lifespan. These cells serve as models for cells that are either difficult to cultivate or have a limited lifespan in vitro. In addition, hTERT over-expressing cells are thought to be a useful resource for tissue engineering and regenerative medicine. While tumour suppressors and cell cycle checkpoints are maintained for an extended period in most hTERT over-expressing cells we found that there is a gradual change in gene expression over a range of 130 population doublings (PD) for the majority of genes analysed. Seven genes were significantly down-regulated with increasing population doublings (PDs), while only two were up-regulated. One gene, stanniocalcin 2, was highly expressed in parental fibroblasts but completely diminished as a consequence of hTERT transgene expression. These data demonstrate that in hTERT over-expressing cells two different types of expression changes occur: one can be directly associated with hTERT transgene expression itself, while others might occur more gradual and with varying kinetics. These changes should be taken into account when these cells are used as functional models or for regenerative purposes.
Asunto(s)
Regeneración , Telomerasa/biosíntesis , Ingeniería de Tejidos , Línea Celular , Fibroblastos/enzimología , Expresión Génica , Humanos , Análisis de Secuencia por Matrices de Oligonucleótidos , Telomerasa/genética , TransgenesRESUMEN
NATs (natural antisense transcripts) are important regulators of eukaryotic gene expression. Interference between the expression of protein-coding sense transcripts and the corresponding NAT is well documented. In the present review, we focus on an additional, higher-order role of NATs that is currently emerging. The recent discovery of endogenous siRNAs (short interfering RNAs), as well as NAT-induced transcriptional gene silencing, are key to the proposed novel function of NATs.
Asunto(s)
Interferencia de ARN/fisiología , ARN sin Sentido/fisiología , Animales , Genoma/fisiología , Humanos , Modelos Biológicos , Regiones Promotoras Genéticas/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transcripción Genética/fisiologíaRESUMEN
Transcriptomic studies are useful for elucidating molecular mechanisms through which changes in nutrient availability produce pleiotropic effects on whole-body and tissue physiology. To further the knowledge of gene-regulatory effects of Zn on tissues important for adult and fetal Zn nutrition, we analysed the responses of human intestinal Caco-2 and placental JAR cells to changes in Zn supply. Analysis of oligonucleotide microarrays demonstrated that, despite the analogous roles of the two tissues in nutrient transfer, different genes respond to changes in Zn availability in intestinal cells compared with placental cells. A number of Fe- and Cu-related genes were identified as targets for regulation by Zn, revealing potential mechanisms underlying reported dietary interactions between Zn and other metals. We established that there are fundamental differences in Zn-regulated transcriptional control in Caco-2 compared with JAR cells. We demonstrated that Zn-induced transcriptional activation of the metallothionein 2A promoter occurs over different, and physiologically relevant, concentration ranges in Caco-2 and JAR cells, indicating that these cell lines sense changes in the extracellular Zn concentration over different ranges. Also, we established that mRNA levels of the Zn-responsive metal response element binding transcription factor (MTF)-1, and its homologue MTF-2, are regulated by Zn in Caco-2 but not JAR cells, which may in part underlie differential gene responses to Zn in intestinal and placental cells. The present study identified a number of novel molecular targets that may underlie symptoms associated with deficient or excessive Zn supply and highlighted the necessity of taking account of cell- and tissue-specific processes when investigating Zn-regulated gene expression in mammals.