RESUMEN

Perivascular macrophages (pvMs) are associated with cerebral vasculature and mediate brain drainage and immune regulation. Here, using reporter mouse models, whole brain and section immunofluorescence, flow cytometry, and single cell RNA sequencing, besides the Lyve1+F4/80+CD206+CX3CR1+ pvMs, we identify a CX3CR1- pvM population that shares phagocytic functions and location. Furthermore, the brain parenchyma vasculature mostly hosts Lyve1+MHCII- pvMs with low to intermediate CD45 expression. Using the double Cx3cr1GFP x Cx3cr1-Cre;RosatdT reporter mice for finer mapping of the lineages, we establish that CD45lowCX3CR1- pvMs are derived from CX3CR1+ precursors and require PU.1 during their ontogeny. In parallel, results from the Cxcr4-CreErt2;Rosa26tdT lineage tracing model support a bone marrow-independent replenishment of all Lyve1+ pvMs in the adult mouse brain. Lastly, flow cytometry and 3D immunofluorescence analysis uncover increased percentage of pvMs following photothrombotic induced stroke. Our results thus show that the parenchymal pvM population is more heterogenous than previously described, and includes a CD45low and CX3CR1- pvM population.

Asunto(s)

Macrófagos , Fagocitos , Animales , Ratones , Recuento de Leucocitos , Citometría de Flujo , Encéfalo

RESUMEN

The identification of disease-causing mutations has in recent years progressed immensely due to whole genome sequencing approaches using patient material. The task accordingly is shifting from gene identification to functional analysis of putative disease-causing genes, preferably in an in vivo setting which also allows testing of drug candidates or biotherapeutics in whole animal disease models. In this review, we highlight the advances made in the field of bone diseases using small laboratory fish, focusing on zebrafish and medaka. We particularly highlight those human conditions where teleost models are available.

Asunto(s)

Enfermedades Óseas/genética , Enfermedades Óseas/fisiopatología , Oryzias/genética , Pez Cebra/genética , Animales , Investigación Biomédica , Modelos Animales de Enfermedad , Genoma/genética , Secuenciación Completa del Genoma

RESUMEN

Atypical E2F transcription factors (E2F7 and E2F8) function as key regulators of cell cycle progression and their inactivation leads to spontaneous cancer formation in mice. However, the mechanism of the tumor suppressor functions of E2F7/8 remain obscure. In this study we discovered that atypical E2Fs control tumor angiogenesis, one of the hallmarks of cancer. We genetically inactivated atypical E2Fs in epithelial and mesenchymal neoplasm and analyzed blood vessel formation in three different animal models of cancer. Tumor formation was either induced by application of 7,12-Dimethylbenz(a)anthracene/12-O-Tetradecanoylphorbol-13-acetate or by Myc/Ras overexpression. To our surprise, atypical E2Fs suppressed tumor angiogenesis in all three cancer models, which is in a sharp contrast to previous findings showing that atypical E2Fs promote angiogenesis during fetal development in mice and zebrafish. Real-time imaging in zebrafish displayed that fluorescent-labeled blood vessels showed enhanced intratumoral branching in xenografted E2f7/8-deficient neoplasms compared with E2f7/8-proficient neoplasms. DLL4 expression, a key negative inhibitor of vascular branching, was decreased in E2f7/8-deficient neoplastic cells, indicating that E2F7/8 might inhibit intratumoral vessel branching via induction of DLL4.

Asunto(s)

Factor de Transcripción E2F7/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas de la Membrana/metabolismo , Neoplasias/patología , Neovascularización Patológica/patología , Proteínas Represoras/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Animales , Proteínas de Unión al Calcio , Carcinógenos/toxicidad , Línea Celular Tumoral , Factor de Transcripción E2F7/genética , Fibroblastos , Regulación Neoplásica de la Expresión Génica , Humanos , Queratinocitos , Ratones , Ratones Noqueados , Ratones Desnudos , Neoplasias/irrigación sanguínea , Neoplasias/inducido químicamente , Neoplasias/genética , Neoplasias Experimentales/irrigación sanguínea , Neoplasias Experimentales/inducido químicamente , Neoplasias Experimentales/genética , Neoplasias Experimentales/patología , Neovascularización Patológica/genética , Cultivo Primario de Células , Proteínas Represoras/genética , Ensayos Antitumor por Modelo de Xenoinjerto , Pez Cebra

RESUMEN

The lymphatic system is lined by endothelial cells and part of the vasculature. It is essential for tissue fluid homeostasis, absorption of dietary fats, and immune surveillance in vertebrates. Misregulation of lymphatic vessel formation and dysfunction of the lymphatic system have been indicated in a number of pathological conditions including lymphedema formation, obesity or chronic inflammatory diseases such as rheumatoid arthritis. In zebrafish, lymphatics were discovered about 10years ago, and the underlying molecular pathways involved in its development have since been studied in detail. Due to its superior live cell imaging possibilities and the broad tool kit for forward and reverse genetics, the zebrafish has become an important model organism to study the development of the lymphatic system during early embryonic development. In the current review, we will focus on the key players during zebrafish lymphangiogenesis and compare the roles of these genes to their mammalian counterparts. In particular, we will focus on novel findings that shed new light on the molecular mechanisms of lymphatic cell fate specification, as well as sprouting and migration of lymphatic precursor cells.

Asunto(s)

Células Endoteliales/ultraestructura , Linfangiogénesis , Vasos Linfáticos/diagnóstico por imagen , Imagen Molecular/métodos , Animales , Artritis Reumatoide/diagnóstico por imagen , Artritis Reumatoide/fisiopatología , Modelos Animales de Enfermedad , Células Endoteliales/patología , Humanos , Vasos Linfáticos/fisiopatología , Linfedema/diagnóstico por imagen , Linfedema/fisiopatología , Obesidad/diagnóstico por imagen , Obesidad/fisiopatología , Pez Cebra/fisiología

RESUMEN

The widespread availability of programmable site-specific nucleases now enables targeted gene disruption in the zebrafish. In this study, we applied site-specific nucleases to generate zebrafish lines bearing individual mutations in more than 20 genes. We found that mutations in only a small proportion of genes caused defects in embryogenesis. Moreover, mutants for ten different genes failed to recapitulate published Morpholino-induced phenotypes (morphants). The absence of phenotypes in mutant embryos was not likely due to maternal effects or failure to eliminate gene function. Consistently, a comparison of published morphant defects with the Sanger Zebrafish Mutation Project revealed that approximately 80% of morphant phenotypes were not observed in mutant embryos, similar to our mutant collection. Based on these results, we suggest that mutant phenotypes become the standard metric to define gene function in zebrafish, after which Morpholinos that recapitulate respective phenotypes could be reliably applied for ancillary analyses.

Asunto(s)

Desoxirribonucleasas/genética , Regulación de la Expresión Génica/efectos de los fármacos , Técnicas de Silenciamiento del Gen/métodos , Morfolinos/farmacología , Mutación/genética , Oligonucleótidos Antisentido/farmacología , Proteínas de Pez Cebra/genética , Pez Cebra/genética , Animales , Western Blotting , Desoxirribonucleasas/metabolismo , Regulación del Desarrollo de la Expresión Génica , Fenotipo , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Pez Cebra/crecimiento & desarrollo , Proteínas de Pez Cebra/antagonistas & inhibidores

RESUMEN

BACKGROUND: The T gene (brachyury gene) is the founding member of the T-box family of transcription factors and is vital for the formation and differentiation of the mesoderm and the axial development of all vertebrates. RESULTS: We report here on four patients from three consanguineous families exhibiting sacral agenesis, a persistent notochordal canal and abnormal ossification of the vertebral bodies, and the identification and characterisation of their underlying genetic defect. Given the consanguineous nature and the similarity of the phenotypes between the three families, we performed homozygosity mapping and identified a common 4.1 Mb homozygous region on chromosome 6q27, containing T, brachyury homologue (mouse) or T. Sequencing of T in the affected individuals led to the identification of a homozygous missense mutation, p.H171R, in the highly conserved T-box. The homozygous mutation results in diminished DNA binding, increased cell growth, and interferes with the normal expression of genes involved in ossification, notochord maintenance and axial mesoderm development. CONCLUSIONS: We have identified a shared homozygous mutation in three families in T and linked it to a novel syndrome consisting of sacral agenesis, a persistent notochordal canal and abnormal ossification of the vertebral bodies. We suggest that screening for the ossification of the vertebrae is warranted in patients with sacral agenesis to evaluate the possible causal involvement of T.

Asunto(s)

Anomalías Múltiples/genética , Proteínas Fetales/genética , Notocorda/anomalías , Osificación Heterotópica/genética , Sacro/anomalías , Columna Vertebral/anomalías , Proteínas de Dominio T Box/genética , Anomalías Múltiples/diagnóstico por imagen , Anomalías Múltiples/mortalidad , Secuencia de Aminoácidos , Secuencia de Bases , Línea Celular Tumoral , Proliferación Celular , Cromosomas Humanos Par 6/genética , Hibridación Genómica Comparativa , Consanguinidad , Femenino , Estudios de Asociación Genética , Homocigoto , Humanos , Lactante , Recién Nacido , Masculino , Mutación Missense , Notocorda/diagnóstico por imagen , Osificación Heterotópica/diagnóstico por imagen , Osificación Heterotópica/mortalidad , Linaje , Unión Proteica , Transporte de Proteínas , Sacro/diagnóstico por imagen , Columna Vertebral/diagnóstico por imagen , Síndrome , Ultrasonografía Prenatal

RESUMEN

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder with impairments across the lifespan. The persistence of ADHD is associated with considerable liability to neuropsychiatric co-morbidity such as depression, anxiety and substance use disorder. The substantial heritability of ADHD is well documented and recent genome-wide analyses for risk genes revealed synaptic adhesion molecules (e.g. latrophilin-3, LPHN3; fibronectin leucine-rich repeat transmembrane protein-3, FLRT3), glutamate receptors (e.g. metabotropic glutamate receptor-5, GRM5) and mediators of intracellular signalling pathways (e.g. nitric oxide synthase-1, NOS1). These genes encode principal components of the molecular machinery that connects pre- and postsynaptic neurons, facilitates glutamatergic transmission, controls synaptic plasticity and empowers intersecting neural circuits to process and refine information. Thus, identification of genetic variation affecting molecules essential for the formation, specification and function of excitatory synapses is refocusing research efforts on ADHD pathogenesis to include the long-neglected glutamate system.

Asunto(s)

Trastorno por Déficit de Atención con Hiperactividad/metabolismo , Cuerpo Estriado/metabolismo , Ácido Glutámico/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neuronas/metabolismo , Transducción de Señal , Transmisión Sináptica , Animales , Trastorno por Déficit de Atención con Hiperactividad/genética , Variación Genética , Humanos , Aprendizaje , Ligandos , Glicoproteínas de Membrana , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/genética , Receptor del Glutamato Metabotropico 5/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Glutamato Metabotrópico/genética , Receptores de Glutamato Metabotrópico/metabolismo , Receptores de Péptidos/genética , Receptores de Péptidos/metabolismo , Sinapsis

RESUMEN

OBJECTIVE: Increasing evidence points to a strong genetic component to osteoarthritis (OA) and that certain changes that occur in osteoarthritic cartilage recapitulate the developmental process of endochondral ossification. As zebrafish are a well validated model for genetic studies and developmental biology, our objective was to establish the spatiotemporal expression pattern of a number of OA susceptibility genes in the larval zebrafish providing a platform for functional studies into the role of these genes in OA. DESIGN: We identified the zebrafish homologues for Mcf2l, Gdf5, PthrP/Pthlh, Col9a2, and Col10a1 from the Ensembl genome browser. Labelled probes were generated for these genes and in situ hybridisations were performed on wild type zebrafish larvae. In addition, we generated transgenic reporter lines by modification of bacterial artificial chromosomes (BACs) containing full length promoters for col2a1 and col10a1. RESULTS: For the first time, we show the spatiotemporal expression pattern of Mcf2l. Furthermore, we show that all six putative OA genes are dynamically expressed during zebrafish larval development, and that all are expressed in the developing skeletal system. Furthermore, we demonstrate that the transgenic reporters we have generated for col2a1 and col10a1 can be used to visualise chondrocyte hypertrophy in vivo. CONCLUSION: In this study we describe the expression pattern of six OA susceptibility genes in zebrafish larvae and the generation of two new transgenic lines marking chondrocytes at different stages of maturation. Moreover, the tools used demonstrate the utility of the zebrafish model for functional studies on genes identified as playing a role in OA.

Asunto(s)

Modelos Animales de Enfermedad , Regulación del Desarrollo de la Expresión Génica/fisiología , Predisposición Genética a la Enfermedad/genética , Osteoartritis/genética , Osteoartritis/fisiopatología , Pez Cebra/genética , Pez Cebra/fisiología , Animales , Animales Modificados Genéticamente , Condrocitos/patología , Cromosomas Artificiales Bacterianos/genética , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Colágeno Tipo II/fisiología , Colágeno Tipo IX/genética , Colágeno Tipo IX/metabolismo , Colágeno Tipo IX/fisiología , Colágeno Tipo X/genética , Colágeno Tipo X/metabolismo , Colágeno Tipo X/fisiología , Factor 5 de Diferenciación de Crecimiento/genética , Factor 5 de Diferenciación de Crecimiento/fisiología , Factores de Intercambio de Guanina Nucleótido/genética , Factores de Intercambio de Guanina Nucleótido/fisiología , Hipertrofia/genética , Proteína Relacionada con la Hormona Paratiroidea/genética , Proteína Relacionada con la Hormona Paratiroidea/fisiología , Pez Cebra/embriología , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismo , Proteínas de Pez Cebra/fisiología

Asunto(s)

Trastorno por Déficit de Atención con Hiperactividad/genética , Conducta Impulsiva/genética , Actividad Motora/fisiología , Receptores de Péptidos/fisiología , Animales , Encéfalo/metabolismo , Regulación hacia Abajo/fisiología , Humanos , Actividad Motora/genética , Receptores de Péptidos/biosíntesis , Pez Cebra

RESUMEN

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity, increased impulsivity and emotion dysregulation. Linkage analysis followed by fine-mapping identified variation in the gene coding for Latrophilin 3 (LPHN3), a putative adhesion-G protein-coupled receptor, as a risk factor for ADHD. In order to validate the link between LPHN3 and ADHD, and to understand the function of LPHN3 in the etiology of the disease, we examined its ortholog lphn3.1 during zebrafish development. Loss of lphn3.1 function causes a reduction and misplacement of dopamine-positive neurons in the ventral diencephalon and a hyperactive/impulsive motor phenotype. The behavioral phenotype can be rescued by the ADHD treatment drugs methylphenidate and atomoxetine. Together, our results implicate decreased Lphn3 activity in eliciting ADHD-like behavior, and demonstrate its correlated contribution to the development of the brain dopaminergic circuitry.

Asunto(s)

Trastorno por Déficit de Atención con Hiperactividad/genética , Diencéfalo/patología , Diencéfalo/fisiopatología , Neuronas Dopaminérgicas/patología , Actividad Motora/genética , Degeneración Nerviosa/genética , Receptores de Péptidos/fisiología , Animales , Clorhidrato de Atomoxetina , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Diencéfalo/crecimiento & desarrollo , Modelos Animales de Enfermedad , Inhibidores de Captación de Dopamina/farmacología , Inhibidores de Captación de Dopamina/uso terapéutico , Neuronas Dopaminérgicas/citología , Neuronas Dopaminérgicas/metabolismo , Técnicas de Silenciamiento del Gen/métodos , Técnicas de Silenciamiento del Gen/psicología , Metilfenidato/farmacología , Metilfenidato/uso terapéutico , Imagen Molecular/métodos , Imagen Molecular/psicología , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Degeneración Nerviosa/patología , Propilaminas/farmacología , Propilaminas/uso terapéutico , Receptores de Péptidos/genética , Pez Cebra

RESUMEN

BACKGROUND: We have used the advantages of the zebrafish model system to demonstrate which of the vertebrate myosin light chain kinase (MLCK) genes is expressed in thrombocytes and important for thrombus formation. METHODS AND RESULTS: Here we report that Mlck1a is an essential component of thrombus formation. Phylogenetic data revealed four zebrafish orthologous for three human MLCK genes. To investigate expression of the zebrafish mlck genes in thrombocytes we compared GFP-tagged platelets with other cells by microarray analysis, and showed that mlck1a expression was 4.5-fold enriched in platelets. Furthermore, mlck1a mRNA and mRNA for the platelet-specific cd41 co-localized in thrombi. Expression of other mlck subtypes was lower in GFP-tagged platelets (mlck1b; 0.77-fold enriched) and absent in thrombi (mlck1b, -2, -3). To investigate the role of Mlck1a in thrombus formation, we knocked down mlck1a using two morpholinos. This resulted in impaired morphology changes of platelets adhering on fibrinogen. In a thrombosis model, in which thrombocytes adhere to the vessel wall damaged by laser irradiation, thrombus formation was slowed down in mlck1a-deficient embryos. CONCLUSION: We conclude that Mlck1a is the subtype of MLCK that contributes to platelet shape change and thrombus formation.

Asunto(s)

Plaquetas/enzimología , Quinasa de Cadena Ligera de Miosina/sangre , Trombosis/enzimología , Proteínas de Pez Cebra/sangre , Pez Cebra/sangre , Animales , Animales Modificados Genéticamente , Forma de la Célula , Modelos Animales de Enfermedad , Fibrinógeno/metabolismo , Perfilación de la Expresión Génica/métodos , Regulación del Desarrollo de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Quinasa de Cadena Ligera de Miosina/genética , Análisis de Secuencia por Matrices de Oligonucleótidos , Adhesividad Plaquetaria , Glicoproteína IIb de Membrana Plaquetaria/sangre , ARN Mensajero/sangre , Proteínas Recombinantes de Fusión/sangre , Trombosis/sangre , Trombosis/genética , Pez Cebra/embriología , Pez Cebra/genética , Proteínas de Pez Cebra/genética

RESUMEN

In Xenopus and zebrafish, BMP2, 4 and 7 have been implicated, after the onset of zygotic expression, in inducing and maintaining ventro-lateral cell fate during early development. We provide evidence here that a maternally expressed bone morphogenetic protein (BMP), Radar, may control early ventral specification in zebrafish. We show that Radar ventralizes zebrafish embryos and induces the early expression of bmp2b and bmp4. The analysis of Radar overexpression in both swirl/bmp2b mutants and embryos expressing truncated BMP receptors shows that Radar-induced ventralization is dependent on functional BMP2/4 pathways, and may initially rely on an Alk6-related signaling pathway. Finally, we show that while radar-injected swirl embryos still exhibit a strongly dorsalized phenotype, the overexpression of Radar into swirl/bmp2b mutant embryos restores ventral marker expression, including bmp4 expression. Our results suggest that a complex regulation of different BMP pathways controls dorso-ventral (DV) patterning from early cleavage stages until somitogenesis.

Asunto(s)

Proteínas Morfogenéticas Óseas/biosíntesis , Proteínas Morfogenéticas Óseas/metabolismo , Linaje de la Célula , Factor de Crecimiento Transformador beta , Proteínas de Pez Cebra , Pez Cebra/embriología , Alelos , Animales , Proteína Morfogenética Ósea 2 , Proteína Morfogenética Ósea 4 , Proteínas Morfogenéticas Óseas/fisiología , Embrión no Mamífero/metabolismo , Femenino , Factor 6 de Diferenciación de Crecimiento , Homocigoto , Hibridación in Situ , Madres , Mutación , Fenotipo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal , Factores de Tiempo , Regulación hacia Arriba , Proteínas de Xenopus , Pez Cebra/genética

RESUMEN

Members of the fibroblast growth factor (Fgf) family are important signaling molecules in several inductive and patterning processes, and act as brain organizer-derived signals during formation of the early vertebrate nervous system. We isolated a new member of the Fgf8/17/18 subgroup of Fgfs from the zebrafish, and studied its expression and function during somitogenesis, optic stalk and midbrain-hindbrain boundary (MHB) development. In spite of a slightly higher aminoacid similarity to Fgf8, expression analysis and mapping to a chromosome stretch that is syntenic with mammalian chromosomes shows that this gene is orthologous to mammalian Fgf17. These data provide a further example of conserved chromosomal organization between zebrafish and mammalian genomes. Using an mRNA injection assay, we show that fgf17 can act similar to fgf8 during gastrulation, when fgf17 is not normally expressed. Direct comparison of the expression patterns of fgf17 and fgf8 suggest however a possible cooperation of these Fgfs at later stages in several tissues requiring Fgf signaling. Analysis of zebrafish MHB mutants demonstrates a gene-dosage dependent requirement of fgf17 expression for the no isthmus// pax2.1 gene, showing that no isthmus/pax2.1 functions upstream of fgf17 at the MHB in a haplo-insufficient manner, similar to what has been reported for mammalian pax2 mutants. In contrast, only maintenance of fgf17 expression is disturbed at the MHB of acerebellar/fgf8 mutants. Consistent with a requirement for fgf8 function, implantation of FGF8-soaked beads induces fgf17 expression, and expression is upregulated in aussicht mutants, which display upregulation of the Fgf8 signaling pathway. Taken together, our results argue that Fgf8 and Fgf17 act as hierarchically organized signaling molecules during development of the MHB organizer and possibly other organizers in the developing nervous system.

Asunto(s)

Factores de Crecimiento de Fibroblastos/genética , Factores de Crecimiento de Fibroblastos/metabolismo , Factores de Crecimiento de Fibroblastos/fisiología , Proteínas de Pez Cebra , Pez Cebra/embriología , Pez Cebra/genética , Secuencia de Aminoácidos , Animales , Mapeo Cromosómico , Clonación Molecular , Secuencia Conservada , ADN Complementario/metabolismo , Factor 8 de Crecimiento de Fibroblastos , Gástrula/metabolismo , Hibridación in Situ , Mesencéfalo/embriología , Modelos Genéticos , Datos de Secuencia Molecular , Filogenia , ARN/metabolismo , ARN Mensajero/metabolismo , Rombencéfalo/embriología , Homología de Secuencia de Aminoácido , Transducción de Señal , Somitos/metabolismo , Factores de Tiempo , Regulación hacia Arriba

Asunto(s)

Genes , Genómica , Mutagénesis , Pez Cebra/fisiología , Animales , Pez Cebra/genética

RESUMEN

Classical embryological studies have implied the existence of an apical ectodermal maintenance factor (AEMF) that sustains signaling from the apical ectodermal ridge (AER) during vertebrate limb development. Recent evidence suggests that AEMF activity is composed of different signals involving both a sonic hedgehog (Shh) signal and a fibroblast growth factor 10 (Fgf10) signal from the mesenchyme. In this study we show that the product of the dackel (dak) gene is one of the components that acts in the epidermis of the zebrafish pectoral fin bud to maintain signaling from the apical fold, which is homologous to the AER of tetrapods. dak acts synergistically with Shh to induce fgf4 and fgf8 expression but independently of Shh in promoting apical fold morphogenesis. The failure of dak mutant fin buds to progress from the initial fin induction phase to the autonomous outgrowth phase causes loss of both AER and Shh activity, and subsequently results in a proximodistal truncation of the fin, similar to the result obtained by ridge ablation experiments in the chicken. Further analysis of the dak mutant phenotype indicates that the activity of the transcription factor engrailed 1 (En1) in the ventral non-ridge ectoderm also depends on a maintenance signal probably provided by the ridge. This result uncovers a new interaction between the AER and the dorsoventral organizer in the zebrafish pectoral fin bud.

Asunto(s)

Ectodermo , Inducción Embrionaria , Proteínas/metabolismo , Transactivadores , Factores de Transcripción , Proteínas de Pez Cebra , Animales , Epidermis/embriología , Extremidades , Factor 4 de Crecimiento de Fibroblastos , Factor 8 de Crecimiento de Fibroblastos , Factores de Crecimiento de Fibroblastos/metabolismo , Genes Homeobox , Proteínas Hedgehog , Proteínas de Homeodominio/metabolismo , Esbozos de los Miembros/embriología , Morfogénesis , Mutación , Proteínas Proto-Oncogénicas/metabolismo , Trasplante de Tejidos , Pez Cebra/embriología

Asunto(s)

Proteínas Morfogenéticas Óseas/fisiología , Proteínas de Unión al ADN/fisiología , Fosfoproteínas/fisiología , Transducción de Señal , Transactivadores/fisiología , Pez Cebra/embriología , Animales , Tipificación del Cuerpo/genética , Tipificación del Cuerpo/fisiología , Fenotipo , Proteínas Smad , Proteína Smad5 , Factor de Crecimiento Transformador beta/fisiología , Pez Cebra/genética , Proteínas de Pez Cebra

RESUMEN

X-linked nonspecific mental retardation (MRX) has a frequency of 0.15% in the male population and is caused by defects in several different genes on the human X chromosome. Genotype-phenotype correlations in male patients with a partial nullisomy of the X chromosome have suggested that at least one locus involved in MRX is on Xp22.3. Previous deletion mapping has shown that this gene resides between markers DXS1060 and DXS1139, a region encompassing approximately 1.5 Mb of DNA. Analyzing the DNA of 15 males with Xp deletions, we were able to narrow this MRX critical interval to approximately 15 kb of DNA. Only one gene, VCX-A (variably charged, X chromosome mRNA on CRI-S232A), was shown to reside in this interval. Because of a variable number of tandem 30-bp repeats in the VCX-A gene, the size of the predicted protein is 186-226 amino acids. VCX-A belongs to a gene family containing at least four nearly identical paralogues on Xp22.3 (VCX-A, -B, -B1, and -C) and two on Yq11.2 (VCY-D, VCY-E), suggesting that the X and Y copies were created by duplication events. We have found that VCX-A is retained in all patients with normal intelligence and is deleted in all patients with mental retardation. There is no correlation between the presence or absence of VCX-B1, -B, and VCX-C and mental status in our patients. These results suggest that VCX-A is sufficient to maintain normal mental development.

Asunto(s)

Deleción Cromosómica , Ligamiento Genético/genética , Discapacidad Intelectual/genética , Proteínas Nucleares/genética , Mapeo Físico de Cromosoma , Cromosoma X/genética , Secuencia de Aminoácidos , Preescolar , Rotura Cromosómica/genética , Clonación Molecular , Eliminación de Gen , Genes Duplicados/genética , Humanos , Hibridación Fluorescente in Situ , Pruebas de Inteligencia , Masculino , Datos de Secuencia Molecular , Familia de Multigenes/genética , Proteínas Nucleares/química , Fenotipo , ARN Mensajero/análisis , ARN Mensajero/genética , Alineación de Secuencia , Cromosoma Y/genética

RESUMEN

Léri-Weill syndrome (LWS) or dyschondrosteosis represents a short stature syndrome characterised by the mesomelic shortening of the forearms and lower legs and by bilateral Madelung deformity of the wrists. Recently, mutations in the pseudoautosomal homeobox gene SHOX have been shown to be causative for this disorder. This gene has previously been described as the short stature gene implicated in Turner syndrome (TS). We studied 32 Léri-Weill patients from 18 different German and Dutch families and present clinical, radiological and molecular data. Phenotypic inter- and intrafamilial heterogeneity is a frequent finding in LWS, and phenotypic manifestations are generally more severe in females. In males, muscular hypertrophy is a frequent finding. To test for SHOX mutations we used FISH, Southern blot and SSCP analysis as well as long-range PCR and sequencing. We identified (sub)microscopic deletions encompassing the SHOX gene region in 10 out of 18 families investigated. Deletion sizes varied between 100 kb and 9 Mb and did not correlate with the severity of the phenotype. We did not detect SHOX mutations in almost half (41%) the LWS families studied, which suggests different genetic etiologies.

Asunto(s)

Proteínas de Homeodominio/genética , Osteocondrodisplasias/genética , Adolescente , Adulto , Southern Blotting , Estatura/genética , Huesos/diagnóstico por imagen , Niño , Deleción Cromosómica , Análisis Mutacional de ADN , Femenino , Antebrazo/diagnóstico por imagen , Variación Genética , Humanos , Hibridación Fluorescente in Situ , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Osteocondrodisplasias/diagnóstico por imagen , Linaje , Fenotipo , Reacción en Cadena de la Polimerasa , Polimorfismo Conformacional Retorcido-Simple , Radiografía , Eliminación de Secuencia , Cromosomas Sexuales/genética , Proteína de la Caja Homeótica de Baja Estatura , Síndrome

Asunto(s)

Ambiente , Tarsiidae/fisiología , Animales , Conservación de los Recursos Naturales , Femenino , Humanos , Indonesia , Masculino , Densidad de Población , Árboles

RESUMEN

BACKGROUND: In many animals, embryonic patterning depends on a careful interplay between cell division and the segregation of localized cellular components. Both of these processes in turn rely on cytoskeletal elements and motor proteins. A type of localized cellular component found in most animals is the germ plasm, a specialized region of cytoplasm that specifies the germ-cell fate. The gene vasa has been shown in Drosophila to encode an essential component of the germ plasm and is thought to have a similar function in other organisms. In the zebrafish embryo, the vasa RNA is localized to the furrows of the early cellular divisions. RESULTS: We identified the gene nebel in a pilot screen for zebrafish maternal-effect mutations. Embryos from females homozygous for a mutation in nebel exhibit defects in cell adhesion. Our analysis provides genetic evidence for a function of the microtubule array that normally develops at the furrow in the deposition of adhesive membrane at the cleavage plane. In addition, nebel mutant embryos show defects in the early localization of vasa RNA. The vasa RNA localization phenotype could be mimicked with microtubule-inhibiting drugs, and confocal microscopy suggests an interaction between microtubules and vasa-RNA-containing aggregates. CONCLUSIONS: Our data support two functions for the microtubule reorganization at the furrow, one for the exocytosis of adhesive membrane, and another for the translocation of vasa RNA along the forming furrow.

Asunto(s)

Tipificación del Cuerpo/genética , Mutación , ARN Helicasas/genética , ARN/genética , ARN/metabolismo , Pez Cebra/embriología , Pez Cebra/genética , Animales , Adhesión Celular/genética , División Celular , ARN Helicasas DEAD-box , Femenino , Homocigoto , Masculino , Microtúbulos/metabolismo , Microtúbulos/ultraestructura , Fenotipo , Xenopus , Pez Cebra/metabolismo , Proteínas de Pez Cebra