RESUMEN
Genome sequencing projects are discovering millions of genetic variants in humans, and interpretation of their functional effects is essential for understanding the genetic basis of variation in human traits. Here we report sequencing and deep analysis of messenger RNA and microRNA from lymphoblastoid cell lines of 462 individuals from the 1000 Genomes Project--the first uniformly processed high-throughput RNA-sequencing data from multiple human populations with high-quality genome sequences. We discover extremely widespread genetic variation affecting the regulation of most genes, with transcript structure and expression level variation being equally common but genetically largely independent. Our characterization of causal regulatory variation sheds light on the cellular mechanisms of regulatory and loss-of-function variation, and allows us to infer putative causal variants for dozens of disease-associated loci. Altogether, this study provides a deep understanding of the cellular mechanisms of transcriptome variation and of the landscape of functional variants in the human genome.
Asunto(s)
Variación Genética/genética , Genoma Humano/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Análisis de Secuencia de ARN , Transcriptoma/genética , Alelos , Línea Celular Transformada , Exones/genética , Perfilación de la Expresión Génica , Humanos , Polimorfismo de Nucleótido Simple/genética , Sitios de Carácter Cuantitativo/genética , ARN Mensajero/análisis , ARN Mensajero/genéticaRESUMEN
A substantial fraction of phenotypic differences between closely related species are likely caused by differences in gene regulation. While this has already been postulated over 30 years ago, only few examples of evolutionary changes in gene regulation have been verified. Here, we identified and investigated binding sites of the transcription factor GA-binding protein alpha (GABPa) aiming to discover cis-regulatory adaptations on the human lineage. By performing chromatin immunoprecipitation-sequencing experiments in a human cell line, we found 11,619 putative GABPa binding sites. Through sequence comparisons of the human GABPa binding regions with orthologous sequences from 34 mammals, we identified substitutions that have resulted in 224 putative human-specific GABPa binding sites. To experimentally assess the transcriptional impact of those substitutions, we selected four promoters for promoter-reporter gene assays using human and African green monkey cells. We compared the activities of wild-type promoters to mutated forms, where we have introduced one or more substitutions to mimic the ancestral state devoid of the GABPa consensus binding sequence. Similarly, we introduced the human-specific substitutions into chimpanzee and macaque promoter backgrounds. Our results demonstrate that the identified substitutions are functional, both in human and nonhuman promoters. In addition, we performed GABPa knock-down experiments and found 1,215 genes as strong candidates for primary targets. Further analyses of our data sets link GABPa to cognitive disorders, diabetes, KRAB zinc finger (KRAB-ZNF), and human-specific genes. Thus, we propose that differences in GABPa binding sites played important roles in the evolution of human-specific phenotypes.
Asunto(s)
Factor de Transcripción de la Proteína de Unión a GA/genética , Factor de Transcripción de la Proteína de Unión a GA/metabolismo , Regulación de la Expresión Génica , Animales , Sitios de Unión , Evolución Biológica , Células COS , Chlorocebus aethiops , Inmunoprecipitación de Cromatina , Mapeo Cromosómico , Evolución Molecular , Especiación Genética , Células HEK293 , Humanos , Regiones Promotoras Genéticas , Unión Proteica , Alineación de Secuencia , Dedos de Zinc/genéticaRESUMEN
MOTIVATION: Protocols to generate strand-specific transcriptomes with next-generation sequencing platforms have been used by the scientific community roughly since 2008. Strand-specific reads allow for detection of antisense events and a higher resolution of expression profiles enabling extension of current transcript annotations. However, applications making use of this strandedness information are still scarce. RESULTS: Here we present a tool (Janus), which focuses on the identification of transcriptional active regions in antisense orientation to known and novel transcribed elements of the genome. Janus can compare the antisense events of multiple samples and assigns scores to identify mutual expression of either transcript in a sense/antisense pair, which could hint to regulatory mechanisms. Janus is able to make use of single-nucleotide variant (SNV) and methylation data, if available, and reports the sense to antisense ratio of regions in the vicinity of the identified genetic and epigenetic variation. Janus interrogates positions of heterozygous SNVs to identify strand-specific allelic imbalance. AVAILABILITY: Janus is written in C/C++ and freely available at http://www.ikmb.uni-kiel.de/janus/janus.html under terms of GNU General Public License, for both, Linux and Windows 64×. Although the binaries will work without additional downloads, the software depends on bamtools (https://github.com/pezmaster31/bamtools) for compilation. A detailed tutorial section is included in the first section of the supplemental material and included as brief readme.txt in the tutorial archive. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
Asunto(s)
Perfilación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , ARN sin Sentido/biosíntesis , Programas Informáticos , Línea Celular Transformada , Metilación de ADN , Variación Genética , HumanosRESUMEN
Nephronophthisis (NPHP) is the most frequent genetic cause of chronic renal failure in children. Identification of four genes mutated in NPHP subtypes 1-4 (refs. 4-9) has linked the pathogenesis of NPHP to ciliary functions. Ten percent of affected individuals have retinitis pigmentosa, constituting the renal-retinal Senior-Loken syndrome (SLSN). Here we identify, by positional cloning, mutations in an evolutionarily conserved gene, IQCB1 (also called NPHP5), as the most frequent cause of SLSN. IQCB1 encodes an IQ-domain protein, nephrocystin-5. All individuals with IQCB1 mutations have retinitis pigmentosa. Hence, we examined the interaction of nephrocystin-5 with RPGR (retinitis pigmentosa GTPase regulator), which is expressed in photoreceptor cilia and associated with 10-20% of retinitis pigmentosa. We show that nephrocystin-5, RPGR and calmodulin can be coimmunoprecipitated from retinal extracts, and that these proteins localize to connecting cilia of photoreceptors and to primary cilia of renal epithelial cells. Our studies emphasize the central role of ciliary dysfunction in the pathogenesis of SLSN.
Asunto(s)
Proteínas de Unión a Calmodulina/genética , Proteínas de Unión a Calmodulina/metabolismo , Calmodulina/metabolismo , Proteínas del Ojo/metabolismo , Mutación , Secuencia de Aminoácidos , Northern Blotting , Proteínas de Unión a Calmodulina/química , Femenino , Humanos , Masculino , Datos de Secuencia Molecular , Linaje , Síndrome , Técnicas del Sistema de Dos HíbridosRESUMEN
Nephronophthisis (NPHP), a group of autosomal recessive cystic kidney disorders, is the most common genetic cause of progressive renal failure in children and young adults. NPHP may be associated with Leber congenital amaurosis, tapeto-retinal degeneration, cerebellar ataxia, cone-shaped epiphyses, congenital oculomotor apraxia and hepatic fibrosis. Loci associated with an infantile type of NPHP on 9q22-q31 (NPHP2), juvenile types of NPHP on chromosomes 2q12-q13 (NPHP1) and 1p36 (NPHP4) and an adolescent type of NPHP on 3q21-q22 (NPHP3) have been mapped. NPHP1 and NPHP4 have been identified, and interaction of the respective encoded proteins nephrocystin and nephrocystin-4 has been shown. Here we report the identification of NPHP3, encoding a novel 1,330-amino acid protein that interacts with nephrocystin. We describe mutations in NPHP3 in families with isolated NPHP and in families with NPHP with associated hepatic fibrosis or tapeto-retinal degeneration. We show that the mouse ortholog Nphp3 is expressed in the node, kidney tubules, retina, respiratory epithelium, liver, biliary tract and neural tissues. In addition, we show that a homozygous missense mutation in Nphp3 is probably responsible for the polycystic kidney disease (pcy) mouse phenotype. Interventional studies in the pcy mouse have shown beneficial effects by modification of protein intake and administration of methylprednisolone, suggesting therapeutic strategies for treating individuals with NPHP3.
Asunto(s)
Enfermedades Renales Quísticas/genética , Cirrosis Hepática/genética , Mutación , Proteínas/genética , Retinitis Pigmentosa/genética , Proteínas Adaptadoras Transductoras de Señales , Adolescente , Adulto , Animales , Línea Celular , Niño , Proteínas del Citoesqueleto , ADN Complementario/genética , Femenino , Humanos , Enfermedades Renales Quísticas/complicaciones , Enfermedades Renales Quísticas/patología , Cirrosis Hepática/complicaciones , Cirrosis Hepática/patología , Masculino , Proteínas de la Membrana , Ratones , Datos de Secuencia Molecular , Riñón Poliquístico Autosómico Recesivo/complicaciones , Riñón Poliquístico Autosómico Recesivo/genética , Riñón Poliquístico Autosómico Recesivo/patología , Proteínas Recombinantes/genética , Retinitis Pigmentosa/complicaciones , Retinitis Pigmentosa/patología , TransfecciónRESUMEN
Primary ciliary dyskinesia (PCD, MIM 242650) is characterized by recurrent infections of the respiratory tract due to reduced mucociliary clearance and by sperm immobility. Half of the affected offspring have situs inversus (reversed organs), which results from randomization of left-right (LR) asymmetry. We previously localized to chromosome 5p a PCD locus containing DNAH5, which encodes a protein highly similar to the Chlamydomonas gamma-dynein heavy chain. Here we characterize the full-length 14-kb transcript of DNAH5. Sequence analysis in individuals with PCD with randomization of LR asymmetry identified mutations resulting in non-functional DNAH5 proteins.
Asunto(s)
Tipificación del Cuerpo/genética , Dineínas/genética , Síndrome de Kartagener/genética , Mutación , Animales , Cilios/ultraestructura , Femenino , Humanos , Masculino , Ratones , Proteínas Motoras Moleculares/genética , Situs Inversus/genéticaRESUMEN
One Health (OH) offers conceptual and applied prospects to advance planetary health and integrative biology in the 21st century. For example, The World Health Organization (WHO) has declared antimicrobial resistance (AMR) one of humanity's top 10 health threats worldwide (AMR). The AMR research, as seen through the OH lens, recognizes the interdependence and the coproduction of the health of humans, nonhuman animals, and the environment (the OH triad). Moreover, research and development (R&D) is required to generate potential solutions to prevent, diagnose, and treat infections and control the spread and emergence of AMR. However, it is still unclear how well the OH approach is integrated into current AMR R&D. In this study, we present a systematic review on the OH funding landscape for cross-sectoral AMR R&D, and its alignment/gaps with the current global strategic agenda on AMR. A systematic literature review was conducted using public databases covering the period between January 2015 and May 2022. We included the studies and reviews on AMR encompassing more than one sector of the OH triad. Out of the 777 included studies, 475 (61%) encompassed the three OH sectors. A key finding of the present systematic review is that the environment was the most neglected sector in the OH triad. AMR surveillance, transmission, and interventions are the most commonly studied priority topics. In addition, both cross-sectoral AMR literature and investments have been increasing since 2017. The operational aspect of AMR is the most researched and funded area. However, certain priority topics in the strategic research and innovation agenda of the Joint Programming Initiative on AMR are underrepresented in OH AMR research, such as diagnosis and therapeutics. To the best of authors' knowledge, this is the first study that systematically reviews the cross-sectoral literature on AMR, classifies it, and aligns and contextualizes it in regard to the funding landscape of AMR. This systematic review identifies neglected areas in AMR R&D and could serve as critical information for policymaking so as to realize the objectives of the Global Action Plan on AMR. Going forward, more cross-sectoral AMR research and funding are needed. As integrative biology and omics systems science are poised to benefit from a rapprochement with the OH lens, the present article highlights the AMR research and funding landscapes.
Asunto(s)
Antibacterianos , Salud Única , Animales , Humanos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Farmacorresistencia Bacteriana , Bases de Datos FactualesRESUMEN
After the completion of a draft human genome sequence, the International Human Genome Sequencing Consortium has proceeded to finish and annotate each of the 24 chromosomes comprising the human genome. Here we describe the sequencing and analysis of human chromosome 3, one of the largest human chromosomes. Chromosome 3 comprises just four contigs, one of which currently represents the longest unbroken stretch of finished DNA sequence known so far. The chromosome is remarkable in having the lowest rate of segmental duplication in the genome. It also includes a chemokine receptor gene cluster as well as numerous loci involved in multiple human cancers such as the gene encoding FHIT, which contains the most common constitutive fragile site in the genome, FRA3B. Using genomic sequence from chimpanzee and rhesus macaque, we were able to characterize the breakpoints defining a large pericentric inversion that occurred some time after the split of Homininae from Ponginae, and propose an evolutionary history of the inversion.
Asunto(s)
Cromosomas Humanos Par 3/genética , Animales , Secuencia de Bases , Rotura Cromosómica/genética , Inversión Cromosómica/genética , Mapeo Contig , Islas de CpG/genética , ADN Complementario/genética , Evolución Molecular , Etiquetas de Secuencia Expresada , Proyecto Genoma Humano , Humanos , Macaca mulatta/genética , Datos de Secuencia Molecular , Pan troglodytes/genética , Análisis de Secuencia de ADN , Sintenía/genéticaRESUMEN
The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. We have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise process that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. LINE1 repeat elements cover one-third of the X chromosome, with a distribution that is consistent with their proposed role as way stations in the process of X-chromosome inactivation. We found 1,098 genes in the sequence, of which 99 encode proteins expressed in testis and in various tumour types. A disproportionately high number of mendelian diseases are documented for the X chromosome. Of this number, 168 have been explained by mutations in 113 X-linked genes, which in many cases were characterized with the aid of the DNA sequence.
Asunto(s)
Cromosomas Humanos X/genética , Evolución Molecular , Genómica , Análisis de Secuencia de ADN , Animales , Antígenos de Neoplasias/genética , Centrómero/genética , Cromosomas Humanos Y/genética , Mapeo Contig , Intercambio Genético/genética , Compensación de Dosificación (Genética) , Femenino , Ligamiento Genético/genética , Genética Médica , Humanos , Masculino , Polimorfismo de Nucleótido Simple/genética , ARN/genética , Secuencias Repetitivas de Ácidos Nucleicos/genética , Homología de Secuencia de Ácido Nucleico , Testículo/metabolismoRESUMEN
Nephronophthisis (NPH), a recessive cystic kidney disease, is the most frequent genetic cause for end-stage renal disease in the first two decades of life. Mutations in three genes (NPHP1, 2, and 3) were identified as causative. Extrarenal manifestations are known, such as retinitis pigmentosa (Senior-Loken syndrome, SLS) and ocular motor apraxia type Cogan. Recently, we identified a novel gene (NPHP4) as mutated in NPH. To date, a total of only 13 different NPHP4 mutations have been described. To determine the frequency of NPHP4 mutations, we performed mutational analysis by direct sequencing of all 30 NPHP4 exons in 250 different patients with isolated NPH, SLS, or Cogan syndrome ascertained worldwide over 14 years. We identified 23 novel NPHP4 sequence variants in 26/250 different patients (10%). Interestingly, we detected homozygous or compound heterozygous mutations of NPHP4 in only 6/250 different patients (2.4%), but only one heterozygous NPHP4 sequence variant in 20/250 different patients (8%). In the six patients with two NPHP4 mutations, 5/8 mutations (63%) were likely loss-of-function mutations, whereas in the 20 patients with only one sequence variant, only 1/20 (5%) was a likely loss-of-function (i.e., truncating) mutation. We conclude that: i) two recessive mutations in NPHP4 are a rare cause of nephronophthisis; ii) single heterozygous NPHP4 sequence variants are three times more prevalent than two recessive mutations; iii) there is no genotype/phenotype correlation; iv) there must exist further genes causing nephronophthisis, since in 224/250 (90%) patients, no sequence variants in either of the four NPH genes were detected.
Asunto(s)
Análisis Mutacional de ADN , Enfermedades Renales/genética , Enfermedades Renales/metabolismo , Mutación , Proteínas/genética , Proteínas/fisiología , Adolescente , Adulto , Niño , Exones , Heterocigoto , Humanos , SíndromeRESUMEN
Hailey-Hailey disease is an autosomal dominant skin disorder characterized by suprabasal cell separation (acantholysis) of the epidermis. Mutations in ATP2C1, the gene encoding a novel, P-type Ca2+-transport ATPase, were recently found to cause Hailey-Hailey disease. In this study, we used conformation-sensitive gel electrophoresis to screen all 28 translated exons of ATP2C1 in 24 Hailey-Hailey disease families and three sporadic cases with the disorder. We identified 22 different mutations, 18 of which have not previously been reported, in 25 probands. The novel mutations comprise three nonsense, six insertion/deletion, three splice-site, and six missense mutations and are distributed throughout the ATP2C1 gene. Six mutations were found in multiple families investigated here or in our previous study. Haplotype analysis revealed that two of these are recurrent mutations that have not been inherited from a common ancestor. Comparison between genotype and phenotype in 23 families failed to yield any clear correlation between the nature of the mutation and clinical features of Hailey-Hailey disease. The extensive interfamilial and intrafamilial phenotypic variability observed suggests that modifying genes and/or environmental factors may greatly influence the clinical features of this disease.
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ATPasas Transportadoras de Calcio/genética , Mutación/fisiología , Pénfigo Familiar Benigno/genética , Pénfigo Familiar Benigno/fisiopatología , Codón sin Sentido , Elementos Transponibles de ADN , Eliminación de Gen , Genotipo , Haplotipos , Humanos , Recién Nacido , Mutación Missense , Fenotipo , Sitios de Empalme de ARN/genéticaRESUMEN
OBJECTIVE: It has been suggested that mono-allelic deletion of the IGF-I receptor gene is causally related to severe intrauterine and postnatal growth deficiency whereas no IGF-I resistance was observed in the patients' fibroblasts. The expression and regulation of the growth-modulating IGF binding proteins (IGFBPs) have been investigated in serum and fibroblasts of a short girl with mono-allelic loss of the distal long arm of chromosome 15 (15q26.1-qter). PATIENT AND METHODS: The mono-allelic loss of the IGF-I receptor (IGF1R) gene was confirmed in a child with prenatal and severe postnatal growth retardation by fluorescence in situ hybridization, and was evaluated on the protein level in fibroblasts of the patient by FACS analysis and IGF cross-linkage. Additionally, expression of IGFBPs and cell-mediated degradation of IGFBP-3 were examined in the patient's fibroblasts. RESULTS: Levels of GH, IGF-I, and IGFBP-3 were above the 95th percentile in the serum of the 3-year-old girl with a mono-allelic deletion of the IGF1R gene, suggesting IGF-I resistance. In the patient's fibroblasts the IGF-I receptor concentration was half that in control cells. Whereas the pattern of secreted IGFBPs in response to IGFs was not altered, the abundance of secreted IGFBPs was higher in the patient's cells than in controls. Moreover, fibroblast-mediated degradation of 125I-labeled IGFBP-3 appears to be reduced in the patient's fibroblasts. The higher abundance of IGFBPs in the patient's fibroblasts might be responsible for the lack of IGF-I-stimulated [alpha-1-14C]methylaminoisobutyric acid transport. CONCLUSION: Our results suggest that the expression and regulation of IGFBPs in tissues from patients with mono-allelic deletion of the IGF-I receptor gene may lead to IGF sequestration and contribute to IGF-I resistance and growth retardation.
Asunto(s)
Deleción Cromosómica , Cromosomas Humanos Par 15 , Fibroblastos/fisiología , Receptor IGF Tipo 1/genética , Estatura/genética , Técnicas de Cultivo de Célula , Preescolar , Femenino , Fibroblastos/citología , Humanos , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/sangre , Factor I del Crecimiento Similar a la Insulina/metabolismoRESUMEN
BACKGROUND: Personalised medicine (PM) is an innovative way to produce better patient outcomes by using an individualised or stratified approach to disease and treatment rather than a collective treatment approach for patients. Despite its tangible advantages, the complex process to translate PM into the member states and European healthcare systems has delayed its uptake. The aim of this study is to identify relevant barriers represented by an index to summarise challenging areas for the implementation of PM in Europe. METHODS: A systematic literature review was conducted, and a gaps-and-needs assessment together with a strengths-weaknesses-opportunities-and-threats analysis were applied to review strategic reports and conduct interviews with key stakeholders. Furthermore, surveys were sent out to representatives of stakeholder groups. The index was constructed based on the priorisation of relevant factors by stakeholders. RESULTS: A need for stakeholder-agreed standards at all levels of implementation of PM exists, from validating biomarkers to definitions of 'informed consent'. The barriers to implement PM are identified in 7 areas, namely, stakeholder involvement, standardisation, interoperable infrastructure, European-level policy making, funding, data and research, and healthcare systems. CONCLUSIONS: Challenges in the above-mentioned areas can and must be successfully tackled if we are to create a healthier Europe through PM. In order to create an environment in which PM can thrive for the patients' best outcomes, there is an urgent need for systematic actions to remove as many barriers as possible.
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Actitud Frente a la Salud , Atención a la Salud , Farmacogenética , Medicina de Precisión/psicología , Política Pública , Recolección de Datos , Europa (Continente) , Femenino , Marcadores Genéticos/genética , Humanos , Formulación de Políticas , Práctica de Salud PúblicaRESUMEN
Molecular medicine is undergoing fundamental changes driving the whole area towards a revolution in modern medicine. The breakthrough was generated the fast-developing technologies in molecular biology since the first draft sequence of the human genome was published. The technological advances enabled the analysis of biological samples from cells and organs to whole organisms in a depth that was not possible before. These technologies are increasingly implemented in the medical and health care system to study diseases and refine diagnostics. As a consequence, the understanding of diseases and the health status of an individual patient is now based on an enormous amount of data that can only be interpreted in the context of the body as a whole. Systems biology as a new field in the life sciences develops new approaches for data integration and interpretation. Systems medicine as a specialized aspect of systems biology combines in an interdisciplinary approach all expertise necessary to decipher the human body in all its complexity. This created new challenges in the area of information and communication technologies to provide the infrastructure and technology needed to cope with the data flood that will accompany the next generation of medicine. The new initiative 'IT Future of Medicine' aims at driving this development even further and integrates not only molecular data (especially genomic information), but also anatomical, physiological, environmental, and lifestyle data in a predictive model approach-the 'virtual patient'-that will allow the clinician or the general practitioner to predict and anticipate the optimal treatment for the individual patient. The application of the virtual patient model will allow truly personalized medicine.
Asunto(s)
Patología Molecular/instrumentación , Patología Molecular/métodos , Medicina de Precisión/instrumentación , Medicina de Precisión/métodos , Atención a la Salud/métodos , HumanosRESUMEN
The IT Future of Medicine (ITFoM, http://www.itfom.eu/) initiative will produce computational models of individuals to enable the prediction of their future health risks, progression of diseases and selection and efficacy of treatments while minimising side effects. To be able to move our health care system to treat patients as individuals rather than as members of larger, divergent groups, the ITFoM initiative, proposes to integrate molecular, physiological and anatomical data of every person in 'virtual patient' models. The establishment of such 'virtual patient' models is now possible due to the enormous progress in analytical techniques, particularly in the '-omics' technology areas and in imaging, as well as in sensor technologies, but also due to the immense developments in the ICT field. As one of six Future and Emerging Technologies (FET) Flagship Pilot Projects funded by the European Commission, ITFoM with more than 150 academic and industrial partners from 34 countries, will foster the development in functional genomics and computer technologies to generate 'virtual patient' models to make them available for clinical application. The increase in the capacity of next generation sequencing systems will enable the high-throughput analysis of a large number of individuals generating huge amounts of genome, epigenome and transcriptome data, but making it feasible to apply deep sequencing in the clinic to characterise not only the patient's genome, but also individual samples, for example, from tumours. The genome profile will be integrated with proteome and metabolome information generated via new powerful chromatography, mass spectrometry and nuclear magnetic resonance techniques. The individualised model will not only enable the analysis of the current situation, but will allow the prediction of the response of the patient to different therapy options or intolerance for certain drugs.
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Biotecnología/métodos , Biología Computacional/métodos , Farmacogenética/métodos , Medicina de Precisión/métodos , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Neoplasias/diagnóstico , Neoplasias/genética , Neoplasias/terapia , Medicina de Precisión/tendencias , Interfaz Usuario-ComputadorRESUMEN
RATIONALE: Primary ciliary dyskinesia (PCD) is characterized by recurrent airway infections and randomization of left-right body asymmetry. To date, autosomal recessive mutations have only been identified in a small number of patients involving DNAI1 and DNAH5, which encode outer dynein arm components. METHODS: We screened 109 white PCD families originating from Europe and North America for presence of DNAH5 mutations by haplotype analyses and/or sequencing. RESULTS: Haplotype analyses excluded linkage in 26 families. In 30 PCD families, we identified 33 novel (12 nonsense, 8 frameshift, 5 splicing, and 8 missense mutations) and two known DNAH5 mutations. We observed clustering of mutations within five exons harboring 27 mutant alleles (52%) of the 52 detected mutant alleles. Interestingly, 6 (32%) of 19 PCD families with DNAH5 mutations from North America carry the novel founder mutation 10815delT. Electron microscopic analyses in 22 patients with PCD with mutations invariably detected outer dynein arm ciliary defects. High-resolution immunofluorescence imaging of respiratory epithelial cells from eight patients with DNAH5 mutations showed mislocalization of mutant DNAH5 and accumulation at the microtubule organizing centers. Mutant DNAH5 was absent throughout the ciliary axoneme in seven patients and remained detectable in the proximal ciliary axoneme in one patient carrying compound heterozygous splicing mutations at the 3'-end (IVS75-2A>T, IVS76+5G>A). In a preselected subpopulation with documented outer dynein arm defects (n = 47), DNAH5 mutations were identified in 53% of patients. CONCLUSIONS: DNAH5 is frequently mutated in patients with PCD exhibiting outer dynein arm defects and mutations cluster in five exons.
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Dineínas/genética , Dineínas/ultraestructura , Síndrome de Kartagener/genética , Dineínas Axonemales , Análisis Mutacional de ADN , Técnica del Anticuerpo Fluorescente , Haplotipos , Humanos , Mutación Missense , Fenotipo , Empalme del ARN , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder characterized by chronic infections of the upper and lower airways, randomization of left/right body asymmetry, and reduced fertility. The phenotype results from dysfunction of motile cilia of the respiratory epithelium, at the embryonic node and of sperm flagella. Ultrastructural defects often involve outer dynein arms (ODAs), that are composed of several light (LCs), intermediate, and heavy (HCs) dynein chains. We recently showed that recessive mutations of DNAH5, the human ortholog of the biflagellate Chlamydomonas ODA gamma-HC, cause PCD. In Chlamydomonas, motor protein activity of the gamma-ODA-HC is regulated by binding of the axonemal LC1. We report the identification of the human (DNAL1) and murine (Dnal1) orthologs of the Chlamydomonas LC1-gene. Northern blot and in situ hybridization analyses revealed specific expression in testis, embryonic node, respiratory epithelium, and ependyma, resembling the DNAH5 expression pattern. In silico protein analysis showed complete conservation of the LC1/gamma-HC binding motif in DNAL1. Protein interaction studies demonstrated binding of DNAL1 and DNAH5. Based on these findings, we considered DNAL1 a candidate for PCD and sequenced all exons of DNAL1 in 86 patients. Mutational analysis was negative, excluding a major role of DNAL1 in the pathogenesis of PCD.
Asunto(s)
Dineínas/química , Síndrome de Kartagener/metabolismo , Tráquea/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Northern Blotting , Línea Celular , Chlamydomonas/metabolismo , Clonación Molecular , Dineínas Citoplasmáticas , Análisis Mutacional de ADN , Bases de Datos Genéticas , Dineínas/biosíntesis , Embrión de Mamíferos/metabolismo , Embrión no Mamífero , Epéndimo/metabolismo , Evolución Molecular , Exones , Etiquetas de Secuencia Expresada , Flagelos/metabolismo , Humanos , Inmunoprecipitación , Hibridación in Situ , Intrones , Pulmón/embriología , Pulmón/patología , Masculino , Ratones , Modelos Moleculares , Datos de Secuencia Molecular , Mutación , Sistemas de Lectura Abierta , Fenotipo , Unión Proteica , Conformación Proteica , Estructura Secundaria de Proteína , ARN Mensajero/metabolismo , Homología de Secuencia de Aminoácido , Especificidad de la Especie , Espermatozoides/metabolismo , Porcinos , Testículo/metabolismoRESUMEN
A contig of overlapping bacterial and P1-derived artificial chromosome (BAC, PAC) clones derived from the inbred rat strain BN was constructed that encompasses the class II and the class III regions of the rat MHC (RT1 complex). The genomic structure of the rat, human, and mouse class II and class III regions is highly similar. However, different from human and mouse, a copy of the C4, Cyp21, and Stk19 genes is found that maps to the class II region in the rat. Gene trees constructed from human, rat, and mouse C4, Cyp21, and Stk19 sequences show species-specific clustering of the duplicated genes. The class II/III contig reported here links two previously published PAC contigs of the BN rat that contain the centromeric and the telomeric class I regions, RT1-A and RT1-C/E/M, respectively. Thus, the MHC of the rat is now completely mapped in a single contig of BAC/PAC clones derived from a single RT1 haplotype and encompasses about 3.7 Mb.
Asunto(s)
Genes MHC Clase II , Antígenos de Histocompatibilidad/genética , Complejo Mayor de Histocompatibilidad , Ratas/genética , Animales , Secuencia de Bases , Mapeo Cromosómico , Cromosomas Artificiales , Humanos , Ratones , Datos de Secuencia Molecular , Filogenia , Ratas Endogámicas BN , Especificidad de la EspecieRESUMEN
The sequence-based map of a part of the rhesus macaque major histocompatibility complex (MHC) extended class II region is presented. The sequenced region encompasses 67,401 bp and contains the SACM2L, RING1, FABGL and KE4 genes, as well as the HTATSF1-like and ZNF-like pseudogenes. Similar to human, but different from rat and mouse, no class I genes are found in the SACM2L- RING1 interval. The rhesus macaque extended MHC class II region shows a high degree of conservation of exonic as well as intronic and intergenic sequences compared with the respective human region. It is concluded that this particular genomic organization of the extended class II region-i.e., the absence of class I genes and the presence of the HTATSF1-like and ZNF-like pseudogenes-can be traced back to a common ancestor of humans and rhesus macaques about 23 million years ago.