RESUMEN
The Samaritans are a group of some 750 indigenous Middle Eastern people, about half of whom live in Holon, a suburb of Tel Aviv, and the other half near Nablus. The Samaritan population is believed to have numbered more than a million in late Roman times but less than 150 in 1917. The ancestry of the Samaritans has been subject to controversy from late Biblical times to the present. In this study, liquid chromatography/electrospray ionization/quadrupole ion trap mass spectrometry was used to allelotype 13 Y-chromosomal and 15 autosomal microsatellites in a sample of 12 Samaritans chosen to have as low a level of relationship as possible, and 461 Jews and non-Jews. Estimation of genetic distances between the Samaritans and seven Jewish and three non-Jewish populations from Israel, as well as populations from Africa, Pakistan, Turkey, and Europe, revealed that the Samaritans were closely related to Cohanim. This result supports the position of the Samaritans that they are descendants from the tribes of Israel dating to before the Assyrian exile in 722-720 BCE. In concordance with previously published single-nucleotide polymorphism haplotypes, each Samaritan family, with the exception of the Samaritan Cohen lineage, was observed to carry a distinctive Y-chromosome short tandem repeat haplotype that was not more than one mutation removed from the six-marker Cohen modal haplotype.
Asunto(s)
Cromosomas Humanos Y/genética , Judíos/genética , Repeticiones de Microsatélite/genética , Variación Genética/genética , Genética de Población , Genotipo , Historia Antigua , Humanos , Israel/etnología , Judíos/historia , Masculino , Reacción en Cadena de la Polimerasa , Polimorfismo de Nucleótido Simple/genética , Análisis de Secuencia de ADN , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
The Samaritan community, which numbered more than a million in late Roman times and only 146 in 1917, numbers today about 640 people representing four large families. They are culturally different from both Jewish and non-Jewish populations in the Middle East and their origin remains a question of great interest. Genetic differences between the Samaritans and neighboring Jewish and non-Jewish populations are corroborated in the present study of 7,280 bp of nonrecombining Y-chromosome and 5,622 bp of coding and hypervariable segment I (HVS-I) mitochondrial DNA (mtDNA) sequences. Comparative sequence analysis was carried out on 12 Samaritan Y-chromosome, and mtDNA samples from nine male and seven female Samaritans separated by at least two generations. In addition, 18-20 male individuals were analyzed, each representing Ethiopian, Ashkenazi, Iraqi, Libyan, Moroccan, and Yemenite Jews, as well as Druze and Palestinians, all currently living in Israel. The four Samaritan families clustered to four distinct Y-chromosome haplogroups according to their patrilineal identity. Of the 16 Samaritan mtDNA samples, 14 carry either of two mitochondrial haplotypes that are rare or absent among other worldwide ethnic groups. Principal component analysis suggests a common ancestry of Samaritan and Jewish patrilineages. Most of the former may be traced back to a common ancestor in the paternally-inherited Jewish high priesthood (Cohanim) at the time of the Assyrian conquest of the kingdom of Israel.
Asunto(s)
Cromosomas Humanos Y/genética , ADN Mitocondrial/genética , Etnicidad/genética , África/etnología , Árabes/genética , Consanguinidad , Etiopía/etnología , Etnicidad/historia , Europa (Continente)/etnología , Femenino , Efecto Fundador , Pool de Genes , Flujo Genético , Variación Genética , Haplotipos/genética , Historia del Siglo XX , Historia Antigua , Humanos , Israel/epidemiología , Judíos/genética , Masculino , Medio Oriente/etnología , Filogenia , Polimorfismo de Nucleótido Simple , Análisis de Secuencia de ADNRESUMEN
The Runx3 transcription factor regulates development of T cells during thymopoiesis and TrkC sensory neurons during dorsal root ganglia neurogenesis. It also mediates transforming growth factor-beta signaling in dendritic cells and is essential for development of skin Langerhans cells. Here, we report that Runx3 is involved in the development of skin dendritic epidermal T cells (DETCs); an important component of tissue immunoregulation. In developing DETCs, Runx3 regulates expression of the alphaEbeta7 integrin CD103, known to affect migration and epithelial retention of DETCs. It also regulates expression of IL-2 receptor beta (IL-2Rbeta) that mediates cell proliferation in response to IL-2 or IL-15. In the absence of Runx3, the reduction in CD103 and IL-2Rbeta expression on Runx3(-/-) DETC precursors resulted in impaired cell proliferation and maturation, leading to complete lack of skin DETCs in Runx3(-/-) mice. The data demonstrate the requirement of Runx3 for DETCs development and underscore the importance of CD103 and IL-2Rbeta in this process. Of note, while Runx3(-/-) mice lack both DETCs and Langerhans cells, the two most important components of skin immune surveillance, the mice did not develop skin lesions under pathogen-free (SPF) conditions.
Asunto(s)
Subunidad alfa 3 del Factor de Unión al Sitio Principal/metabolismo , Células de Langerhans/citología , Células de Langerhans/metabolismo , Linfocitos T/citología , Linfocitos T/metabolismo , Animales , Antígenos CD/metabolismo , Secuencia de Bases , Diferenciación Celular , Proliferación Celular , Subunidad alfa 3 del Factor de Unión al Sitio Principal/deficiencia , Subunidad alfa 3 del Factor de Unión al Sitio Principal/genética , Cartilla de ADN/genética , Regulación del Desarrollo de la Expresión Génica , Cadenas alfa de Integrinas/metabolismo , Subunidad beta del Receptor de Interleucina-2/metabolismo , Células de Langerhans/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos ICR , Ratones Noqueados , Piel/citología , Piel/embriología , Piel/inmunología , Piel/metabolismo , Linfocitos T/inmunologíaRESUMEN
Lymphocyte motility in lymph nodes is regulated by chemokines, but the contribution of integrins to this motility remains obscure. Here we examined lymphocyte migration over CCR7-binding chemokines that 'decorate' lymph node stroma. In a shear-free environment, surface-bound lymph node chemokines but not their soluble counterparts promoted robust and sustained T lymphocyte motility. The chemokine CCL21 induced compartmentalized clustering of the integrins LFA-1 and VLA-4 in motile lymphocytes, but both integrins remained nonadhesive to ligands on lymphocytes, dendritic cells and stroma. The application of shear stress to lymphocytes interacting with CCL21 and integrin ligands promoted robust integrin-mediated adhesion. Thus, lymph node chemokines that promote motility and strongly activate lymphocyte integrins under shear forces fail to stimulate stable integrin adhesiveness in extravascular shear-free environments.
Asunto(s)
Quimiocina CCL21/fisiología , Integrinas/fisiología , Ganglios Linfáticos/inmunología , Linfocitos T/fisiología , Animales , Adhesión Celular , Movimiento Celular , Humanos , Molécula 1 de Adhesión Intercelular/fisiología , Antígeno-1 Asociado a Función de Linfocito/fisiología , Ratones , Ratones Endogámicos BALB C , Microtúbulos/fisiología , Resistencia al Corte , Molécula 1 de Adhesión Celular Vascular/fisiologíaRESUMEN
Regulation of gene expression by tissue-specific transcription factors involves both turning on and turning off transcription of target genes. Runx3, a runt-domain transcription factor, regulates cell-intrinsic functions by activating and repressing gene expression in sensory neurons, dendritic cells (DC), and T cells. To investigate the mechanism of Runx3-mediated repression in an in vivo context, we generated mice expressing a mutant Runx3 lacking the C-terminal VWRPY, a motif required for Runx3 interaction with the corepressor Groucho/transducin-like Enhancer-of-split (TLE). In contrast with Runx3(-/-) mice, which displayed ataxia due to the death of dorsal root ganglia TrkC neurons, Runx3(VWRPY-/-) mice were not ataxic and had intact dorsal root ganglia neurons, indicating that ability of Runx3 to tether Groucho/TLE is not essential for neurogenesis. In the DC compartment, the mutant protein Runx3(VWRPY-) promoted normally developed skin Langerhans cells but failed to restrain DC spontaneous maturation, indicating that this latter process involves Runx3-mediated repression through recruitment of Groucho/TLE. Moreover, in CD8(+) thymocytes, Runx3(VWRPY-) up-regulated alphaE/CD103-like WT Runx3, whereas unlike wild type, it failed to repress alphaE/CD103 in CD8(+) splenocytes. Thus, in CD8-lineage T cells, Runx3 regulates alphaE/CD103 in opposing regulatory modes and recruits Groucho/TLE to facilitate the transition from activation to repression. Runx3(VWRPY-) also failed to mediate the epigenetic silencing of CD4 gene in CD8(+) T cells, but normally regulated other pan-CD8(+) T cell genes. These data provide evidence for the requirement of Groucho/TLE for Runx3-mediated epigenetic silencing of CD4 and pertain to the mechanism through which other Runx3-regulated genes are epigenetically silenced.
Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Subunidad alfa 3 del Factor de Unión al Sitio Principal/metabolismo , Proteínas Represoras/metabolismo , Secuencia de Aminoácidos , Animales , Antígenos CD/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Antígenos CD4/metabolismo , Linfocitos T CD8-positivos/metabolismo , Diferenciación Celular , Células Cultivadas , Chlorocebus aethiops , Subunidad alfa 3 del Factor de Unión al Sitio Principal/química , Subunidad alfa 3 del Factor de Unión al Sitio Principal/genética , Células Dendríticas/citología , Células Dendríticas/metabolismo , Regulación hacia Abajo , Elementos de Facilitación Genéticos , Regulación de la Expresión Génica , Humanos , Cadenas alfa de Integrinas/metabolismo , Ratones , Ratones Noqueados , Fenotipo , Proteínas Represoras/genética , Transcripción Genética/genéticaRESUMEN
Rac GTPases are key regulators of leukocyte motility. In lymphocytes, chemokine-mediated Rac activation depends on the CDM adaptor DOCK2. The present studies addressed the role of DOCK2 in chemokine-triggered lymphocyte adhesion and motility. Rapid chemokine-triggered activation of both LFA-1 and VLA-4 integrins took place normally in DOCK2-/- T lymphocytes under various shear flow conditions. Consequently, DOCK2-/- T cells arrested normally on TNFalpha-activated endothelial cells in response to integrin stimulatory chemokine signals, and their resistance to detachment was similar to that of wild-type (wt) T lymphocytes. Nevertheless, DOCK2-/- T lymphocytes exhibited reduced microvillar collapse and lamellipodium extension in response to chemokine signals, ruling out a role for these events in integrin-mediated adhesion strengthening. Strikingly, arrested DOCK2-/- lymphocytes transmigrated through a CCL21-presenting endothelial barrier with similar efficiency and rate as wt lymphocytes but, unlike wt lymphocytes, could not locomote away from the transmigration site of the basal endothelial side. DOCK2-/- lymphocytes also failed to laterally migrate over multiple integrin ligands coimmobilized with chemokines. This is a first indication that T lymphocytes use 2 different chemokine-triggered actin remodeling programs: the first, DOCK2 dependent, to locomote laterally along apical and basal endothelial surfaces; the second, DOCK2 independent, to cross through a chemokine-bearing endothelial barrier.
Asunto(s)
Quimiocinas/metabolismo , Células Endoteliales/citología , Proteínas Activadoras de GTPasa/genética , Proteínas Activadoras de GTPasa/fisiología , Linfocitos/metabolismo , Actinas/metabolismo , Animales , Movimiento Celular , Quimiocina CCL21 , Quimiocinas CC , Matriz Extracelular/metabolismo , Factores de Intercambio de Guanina Nucleótido , Ligandos , Linfocitos/citología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Linfocitos T/citologíaRESUMEN
RUNX transcription factors are key regulators of lineage-specific gene expression and might be involved in autoimmune diseases. Runx3 plays a role during the development of sensory neurons and T cells and regulates transforming growth factor beta (TGF-beta) signaling in dendritic cells. Here, we report that at 4 weeks of age, Runx3 knockout (KO) mice spontaneously develop inflammatory bowel disease (IBD) characterized by leukocyte infiltration, mucosal hyperplasia, formation of lymphoid clusters, and increased production of IgA. Additionally, at a considerably older age (8 months), the KO mice also develop progressive hyperplasia of the gastric mucosa associated with disturbed epithelial differentiation and cellular hyaline degeneration. Analysis of cytokines in the colonic mucosa of Runx3 KO mice revealed a mixed T helper 1/T helper 2 response. By using immunohistochemistry and RNA in situ hybridization, Runx3 expression in the gastrointestinal tract is detected in lymphoid and myeloid populations but not in the epithelium. The data indicate that loss of leukocytic cell-autonomous function of Runx3 results in IBD and gastric lesion in the KO mice. IBD in humans is viewed as a complex genetic disorder. Several susceptibility loci were identified on different human chromosomes including the chromosomal region 1p36 where RUNX3 resides. It is thus tempting to speculate that mutations in RUNX3 may constitute an IBD risk factor in humans.
Asunto(s)
Colitis/etiología , Proteínas de Unión al ADN/deficiencia , Mucosa Gástrica/patología , Leucocitos/fisiología , Factores de Transcripción/deficiencia , Animales , Colitis/genética , Colitis/patología , Colitis/fisiopatología , Subunidad alfa 3 del Factor de Unión al Sitio Principal , Citocinas/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/fisiología , Mucosa Gástrica/inmunología , Humanos , Hiperplasia , Inmunohistoquímica , Hibridación in Situ , Enfermedades Inflamatorias del Intestino/etiología , Enfermedades Inflamatorias del Intestino/genética , Enfermedades Inflamatorias del Intestino/patología , Enfermedades Inflamatorias del Intestino/fisiopatología , Leucocitos/patología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Células TH1/inmunología , Células TH1/patología , Células Th2/inmunología , Células Th2/patología , Factores de Transcripción/genética , Factores de Transcripción/fisiologíaRESUMEN
Runx3 transcription factor regulates cell lineage decisions in thymopoiesis and neurogenesis. Here we report that Runx3 knockout (KO) mice develop spontaneous eosinophilic lung inflammation associated with airway remodeling and mucus hypersecretion. Runx3 is specifically expressed in mature dendritic cells (DC) and mediates their response to TGF-beta. In the absence of Runx3, DC become insensitive to TGF-beta-induced maturation inhibition, and TGF-beta-dependent Langerhans cell development is impaired. Maturation of Runx3 KO DC is accelerated and accompanied by increased efficacy to stimulate T cells and aberrant expression of beta2-integrins. Lung alveoli of Runx3 KO mice accumulate DC characteristic of allergic airway inflammation. Taken together, abnormalities in DC function and subset distribution may constitute the primary immune system defect, which leads to the eosinophilic lung inflammation in Runx3 KO mice. These data may help elucidate the molecular mechanisms underlying the pathogenesis of allergic airway inflammation in humans.
Asunto(s)
Proteínas de Unión al ADN/fisiología , Células Dendríticas/metabolismo , Neumonía/inmunología , Factores de Transcripción/fisiología , Factor de Crecimiento Transformador beta/fisiología , Animales , Líquido del Lavado Bronquioalveolar/citología , Antígenos CD18/biosíntesis , Células Cultivadas , Subunidad alfa 3 del Factor de Unión al Sitio Principal , Proteínas de Unión al ADN/biosíntesis , Proteínas de Unión al ADN/genética , Células Dendríticas/patología , Eosinófilos/patología , Ratones , Ratones Noqueados , Moco/metabolismo , Neumonía/patología , Alveolos Pulmonares/patología , Transducción de Señal , Linfocitos T/metabolismo , Linfocitos T/patología , Factores de Transcripción/biosíntesis , Factores de Transcripción/genéticaRESUMEN
The RUNX transcription factors are important regulators of lineage-specific gene expression. RUNX are bifunctional, acting both as activators and repressors of tissue-specific target genes. Recently, we have demonstrated that Runx3 is a neurogenic transcription factor, which regulates development and survival of proprioceptive neurons in dorsal root ganglia. Here we report that Runx3 and Runx1 are highly expressed in thymic medulla and cortex, respectively, and function in development of CD8 T cells during thymopoiesis. Runx3-deficient (Runx3 KO) mice display abnormalities in CD4 expression during lineage decisions and impairment of CD8 T cell maturation in the thymus. A large proportion of Runx3 KO peripheral CD8 T cells also expressed CD4, and in contrast to wild-type, their proliferation ability was largely reduced. In addition, the in vitro cytotoxic activity of alloimmunized peritoneal exudate lymphocytes was significantly lower in Runx3 KO compared with WT mice. In a compound mutant mouse, null for Runx3 and heterozygous for Runx1 (Runx3-/-;Runx1+/-), all peripheral CD8 T cells also expressed CD4, resulting in a complete lack of single-positive CD8+ T cells in the spleen. The results provide information on the role of Runx3 and Runx1 in thymopoiesis and suggest that both act as transcriptional repressors of CD4 expression during T cell lineage decisions.
Asunto(s)
Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/metabolismo , Proteínas de Unión al ADN/fisiología , Proteínas Proto-Oncogénicas , Timo/citología , Factores de Transcripción/fisiología , Animales , Antígenos CD4/biosíntesis , Linfocitos T CD4-Positivos/metabolismo , División Celular , Linaje de la Célula , Subunidad alfa 2 del Factor de Unión al Sitio Principal , Subunidad alfa 3 del Factor de Unión al Sitio Principal , Citometría de Flujo , Inmunohistoquímica , Ratones , Ratones Noqueados , Bazo/metabolismo , Timo/metabolismoRESUMEN
The RUNX transcription factors are important regulators of linage-specific gene expression in major developmental pathways. Recently, we demonstrated that Runx3 is highly expressed in developing cranial and dorsal root ganglia (DRGs). Here we report that within the DRGs, Runx3 is specifically expressed in a subset of neurons, the tyrosine kinase receptor C (TrkC) proprioceptive neurons. We show that Runx3-deficient mice develop severe limb ataxia due to disruption of monosynaptic connectivity between intra spinal afferents and motoneurons. We demonstrate that the underlying cause of the defect is a loss of DRG proprioceptive neurons, reflected by a decreased number of TrkC-, parvalbumin- and beta-galactosidase-positive cells. Thus, Runx3 is a neurogenic TrkC neuron-specific transcription factor. In its absence, TrkC neurons in the DRG do not survive long enough to extend their axons toward target cells, resulting in lack of connectivity and ataxia. The data provide new genetic insights into the neurogenesis of DRGs and may help elucidate the molecular mechanisms underlying somatosensory-related ataxia in humans.
Asunto(s)
Ataxia/genética , Proteínas de Unión al ADN/fisiología , Ganglios Espinales/patología , Regulación del Desarrollo de la Expresión Génica , Proteínas del Tejido Nervioso/fisiología , Neuronas Aferentes/citología , Propiocepción/fisiología , Receptor trkC/análisis , Trastornos Somatosensoriales/genética , Factores de Transcripción/fisiología , Vías Aferentes/fisiopatología , Animales , Ataxia/patología , Ataxia/fisiopatología , Axones/ultraestructura , Biomarcadores , Muerte Celular , Subunidad alfa 3 del Factor de Unión al Sitio Principal , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Ganglios Espinales/química , Genotipo , Ratones , Ratones Endogámicos ICR , Ratones Noqueados , Ratones Mutantes Neurológicos , Neuronas Motoras/fisiología , Husos Musculares/patología , Proteínas del Tejido Nervioso/análisis , Proteínas del Tejido Nervioso/deficiencia , Proteínas del Tejido Nervioso/genética , Parvalbúminas/análisis , Propiocepción/genética , Trastornos Somatosensoriales/patología , Trastornos Somatosensoriales/fisiopatología , Médula Espinal/patología , Sinapsis/patología , Transmisión Sináptica , Factores de Transcripción/deficiencia , Factores de Transcripción/genética , Ganglio del Trigémino/química , Ganglio del Trigémino/patología , beta-Galactosidasa/análisisRESUMEN
The RUNX transcription factors are key regulators of lineage specific gene expression in developmental pathways. The mammalian RUNX genes arose early in evolution and maintained extensive structural similarities. Sequence analysis suggested that RUNX3 is the most ancient of the three mammalian genes, consistent with its role in neurogenesis of the monosynaptic reflex arc, the simplest neuronal response circuit, found in Cnidarians, the most primitive animals. All RUNX proteins bind to the same DNA motif and act as activators or repressors of transcription through recruitment of common transcriptional modulators. Nevertheless, analysis of Runx1 and Runx3 expression during embryogenesis revealed that their function is not redundant. In adults both Runx1 and Runx3 are highly expressed in the hematopoietic system. At early embryonic stages we found strong Runx3 expression in dorsal root ganglia neurons, confined to TrkC sensory neurons. In the absence of Runx3, knockout mice develop severe ataxia due to the early death of the TrkC neurons. Other phenotypic defects of Runx3 KO mice including abnormalities in thymopoiesis are also being investigated.