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1.
Cell Rep ; 43(5): 114145, 2024 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-38669141

RESUMEN

Acute myeloid leukemia (AML) is an aggressive disease with a poor prognosis (5-year survival rate of 30.5% in the United States). Designing cell therapies to target AML is challenging because no single tumor-associated antigen (TAA) is highly expressed on all cancer subpopulations. Furthermore, TAAs are also expressed on healthy cells, leading to toxicity risk. To address these targeting challenges, we engineer natural killer (NK) cells with a multi-input gene circuit consisting of chimeric antigen receptors (CARs) controlled by OR and NOT logic gates. The OR gate kills a range of AML cells from leukemic stem cells to blasts using a bivalent CAR targeting FLT3 and/or CD33. The NOT gate protects healthy hematopoietic stem cells (HSCs) using an inhibitory CAR targeting endomucin, a protective antigen unique to healthy HSCs. NK cells with the combined OR-NOT gene circuit kill multiple AML subtypes and protect primary HSCs, and the circuit also works in vivo.


Asunto(s)
Células Asesinas Naturales , Leucemia Mieloide Aguda , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Humanos , Leucemia Mieloide Aguda/terapia , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/inmunología , Animales , Ratones , Receptores Quiméricos de Antígenos/metabolismo , Receptores Quiméricos de Antígenos/inmunología , Redes Reguladoras de Genes , Células Madre Hematopoyéticas/metabolismo , Línea Celular Tumoral , Medicina de Precisión/métodos , Tratamiento Basado en Trasplante de Células y Tejidos/métodos
2.
Genes Dev ; 32(9-10): 723-736, 2018 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-29764918

RESUMEN

The K50 (lysine at amino acid position 50) homeodomain (HD) protein Orthodenticle (Otd) is critical for anterior patterning and brain and eye development in most metazoans. In Drosophila melanogaster, another K50HD protein, Bicoid (Bcd), has evolved to replace Otd's ancestral function in embryo patterning. Bcd is distributed as a long-range maternal gradient and activates transcription of a large number of target genes, including otd Otd and Bcd bind similar DNA sequences in vitro, but how their transcriptional activities are integrated to pattern anterior regions of the embryo is unknown. Here we define three major classes of enhancers that are differentially sensitive to binding and transcriptional activation by Bcd and Otd. Class 1 enhancers are initially activated by Bcd, and activation is transferred to Otd via a feed-forward relay (FFR) that involves sequential binding of the two proteins to the same DNA motif. Class 2 enhancers are activated by Bcd and maintained by an Otd-independent mechanism. Class 3 enhancers are never bound by Bcd, but Otd binds and activates them in a second wave of zygotic transcription. The specific activities of enhancers in each class are mediated by DNA motif variants preferentially bound by Bcd or Otd and the presence or absence of sites for cofactors that interact with these proteins. Our results define specific patterning roles for Bcd and Otd and provide mechanisms for coordinating the precise timing of gene expression patterns during embryonic development.


Asunto(s)
Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/embriología , Drosophila melanogaster/genética , Regulación del Desarrollo de la Expresión Génica , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Transactivadores/genética , Transactivadores/metabolismo , Secuencias de Aminoácidos , Animales , Tipificación del Cuerpo/genética , Drosophila melanogaster/metabolismo , Desarrollo Embrionario/efectos de los fármacos , Desarrollo Embrionario/genética , Elementos de Facilitación Genéticos/genética , Unión Proteica
3.
Eur Urol Focus ; 4(1): 128-138, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28753805

RESUMEN

CONTEXT: The urinary tract, previously considered a sterile body niche, has emerged as the host of an array of bacteria in healthy individuals, revolutionizing the urology research field. OBJECTIVE: To review the literature on microbiome implications in the urinary tract and the usefulness of probiotics/prebiotics and diet as treatment for urologic disorders. EVIDENCE ACQUISITION: A systematic review was conducted using PubMed and Medline from inception until July 2016. The initial search identified 1419 studies and 89 were included in this systematic review. EVIDENCE SYNTHESIS: Specific bacterial communities have been found in the healthy urinary tract. Changes in this microbiome have been observed in certain urologic disorders such as urinary incontinence, urologic cancers, interstitial cystitis, neurogenic bladder dysfunction, sexually transmitted infections, and chronic prostatitis/chronic pelvic pain syndrome. The role of probiotics, prebiotics, and diet as treatment or preventive agents for urologic disorders requires further investigation. CONCLUSIONS: There is a microbiome associated with the healthy urinary tract that can change in urologic disorders. This represents a propitious context to identify new diagnostic, prognostic, and predictive microbiome-based biomarkers that could be used in clinical urology practice. In addition, probiotics, prebiotics, and diet modifications appear to represent an opportunity to regulate the urinary microbiome. PATIENT SUMMARY: We review the urinary microbiome of healthy individuals and its changes in relation to urinary disorders. The question to resolve is how we can modulate the microbiome to improve urinary tract health.


Asunto(s)
Microbiota/fisiología , Prostatitis/microbiología , Incontinencia Urinaria/microbiología , Sistema Urinario/microbiología , Enfermedades Urológicas/dietoterapia , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Bacterias/genética , Biomarcadores/metabolismo , Femenino , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Prebióticos/efectos adversos , Probióticos/uso terapéutico , ARN Ribosómico 16S/genética , Enfermedades Urológicas/microbiología , Adulto Joven
4.
Rheumatol Int ; 38(1): 67-74, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28828621

RESUMEN

The aim of this study is to present demographic and clinical features, MEFV mutation variations, and treatment response of a large number of pediatric familial Mediterranean fever (FMF) patients from a single tertiary centre. Moreover, we aimed to investigate the current outcome of FMF, namely frequency of amyloidosis in children with FMF. We evaluated 708 FMF patients who were followed up in our clinic and who were under colchicine treatment for at least 6 months. The data were recorded from patient records and also verified by negotiations with patients and parents. The male/female proportion of the cohort was 1.05/1 (n = 362/346). Abdominal pain (89.5%, n = 634) was the most common manifestation of FMF episodes, followed by fever (88.8%, n = 629) and arthritis (40.7%, n = 288). However, arthritis in 23 (8%) of the 288 cases was not self-limited; and they subsequently diagnosed with juvenile idiopathic arthritis in addition to FMF. Homozygote or heterozygote M694V mutation was more frequent in patients with arthritis (63.2%) and chronic arthritis (69.6%) than the whole cohort (53.8%). Erythrocyte sedimentation rate and CRP level were in high levels even during attack-free period in 13.9% (n = 97/697) and 11% (n = 78/670) of the patients, respectively. Proteinuria was found in ten patients (1.4%). Amyloidosis was confirmed by renal biopsy in only two of these cases who were homozygous for M694V and compound heterozygous for M694V/M680I. 47 (6.6%) subjects were considered as colchicine resistant. Homozygote M694V mutation was the most frequent mutation in those resistant cases (63.8%, n = 30), followed by compound heterozygote mutation of M694V/M680I (6.3%, n = 3). Homozygous M694V mutation are still the most frequent mutation and associated with the most severe clinical picture and the worst outcome in Turkish children. M694V genotype seems to be more frequently associated with arthritis as well as with chronic arthritis than other genotypes. Recurrence of FMF episodes as well as amyloidosis could only be managed via strict compliance to colchicine treatment. Frequency of amyloidosis significantly decreased compared to the previous studies. A favorable outcome could be obtained with the anti IL-1 in colchicine-resistant FMF patients.


Asunto(s)
Dolor Abdominal/etiología , Amiloidosis/etiología , Colchicina/uso terapéutico , Fiebre Mediterránea Familiar/complicaciones , Pirina/genética , Moduladores de Tubulina/uso terapéutico , Dolor Abdominal/genética , Adolescente , Amiloidosis/genética , Niño , Preescolar , Fiebre Mediterránea Familiar/diagnóstico , Fiebre Mediterránea Familiar/tratamiento farmacológico , Fiebre Mediterránea Familiar/genética , Femenino , Genotipo , Humanos , Lactante , Masculino , Mutación , Resultado del Tratamiento
5.
Nucl Med Commun ; 39(2): 131-139, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29257007

RESUMEN

OBJECTIVE: Radioiodine-131 is a radionuclide that is used for therapeutic purposes in hyperthyroidism and thyroid cancer. The aim of this study was to evaluate apoptotosis and proliferative changes in radioiodine-related kidney damage. MATERIALS AND METHODS: Three groups (n=10/group) of rats were used as follows: the rats were in group 1 untreated, and the rats in groups 2 and 3 were treated once with oral radioiodine (111 MBq). The animals in group 2 were killed at the end of the seventh day and the rats in group 3 were killed at the end of the 10th week. The kidneys were removed and evaluated immunohistochemically. The presence of radioiodine in the kidneys was shown by the Na+/I-symporter antibody and proliferating cell nuclear antigen, Ki-67, caspase-3, caspase-8, caspase-9, and terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling assay were used to detect cell proliferation and apoptosis. RESULTS: Na+/I-symporter protein accumulation in the kidneys was observed to be significantly greater in group 2 than in group 3 (P<0.05). All the immunohistochemical analyses showed that cell proliferation and apoptosis began on the seventh day and peaked in the 10th week. The proliferating cell nuclear antigen, Ki-67, and caspase expressions and terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling values were all found to be statistically significantly increased in group 3 compared with the other groups (P<0.05). CONCLUSION: Radioiodine caused cell proliferation and apoptosis as shown by immunohistochemistry.


Asunto(s)
Apoptosis/efectos de la radiación , Radioisótopos de Yodo/efectos adversos , Riñón/metabolismo , Riñón/efectos de la radiación , Animales , Caspasas/metabolismo , Proliferación Celular/efectos de la radiación , Roturas del ADN/efectos de la radiación , Femenino , Inmunohistoquímica , Riñón/patología , Ratas , Ratas Wistar , Factores de Tiempo
6.
Drug Res (Stuttg) ; 67(2): 103-110, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27824430

RESUMEN

Purpose: Relatively little is known about gender-dependent susceptibility to hepatic injury induced by nutritional factors. In the current study, we investigated dietary fructose-induced hepatic degeneration and roles of endothelial nitric oxide synthase (eNOS), insulin receptor (IRß) and substrate-1 (IRS-1) expressions in association with inflammatory markers in male and female rats. Moreover, we examined potential effect of resveratrol on fructose-induced changes. Methods: Male and female rats were divided into 4 groups as control, resveratrol, fructose and resveratrol plus fructose. All rats were fed with a standard diet with or without resveratrol (500 mg/kg). Fructose was given as 10% in drinking waterfor 24 weeks. Results: Long-term dietary fructose caused parenchymal degeneration and hyperemia in association with impaired eNOS mRNA/protein expressions in liver of male and female rats. This dietary intervention also led to increases in hepatic triglyceride content, TNFα and IL-1ß levels in both genders. Gender-related differences to consequence of fructose consumption were not obvious. Resveratrol supplementation markedly attenuated hepatic degeneration, hyperemia and triglyceride content in association with reduced TNFα and IL-1ß levels, but enhanced IRß mRNA and IRS-1 protein, in male and female rats upon fructose feeding. Conclusion: Long-term dietary fructose causes hepatic degeneration possibly via a decrease in eNOS, but increase in TNFα and IL-1ß, in both genders. Resveratrol supplementation improved fructose-induced hepatic injury.


Asunto(s)
Antioxidantes/farmacología , Dieta de Carga de Carbohidratos/efectos adversos , Fructosa/efectos adversos , Hígado/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo III/metabolismo , Enfermedad del Hígado Graso no Alcohólico/inducido químicamente , Enfermedad del Hígado Graso no Alcohólico/enzimología , Estilbenos/farmacología , Animales , Antioxidantes/administración & dosificación , Biomarcadores/sangre , Peso Corporal/efectos de los fármacos , Femenino , Fructosa/administración & dosificación , Jarabe de Maíz Alto en Fructosa/administración & dosificación , Jarabe de Maíz Alto en Fructosa/efectos adversos , Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/metabolismo , Interleucina-1beta/metabolismo , Hígado/enzimología , Hígado/patología , Masculino , Enfermedad del Hígado Graso no Alcohólico/patología , Ratas , Ratas Wistar , Receptor de Insulina/metabolismo , Resveratrol , Transducción de Señal , Estilbenos/administración & dosificación , Triglicéridos/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo
7.
J Ethnopharmacol ; 185: 370-6, 2016 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-26947902

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: The roots and root barks of Echium sp. have been used to treat ulcers, burns and wounds in traditional Turkish medicine. AIM OF THE STUDY: On the basis of them traditional use and literature references, four Echium species were selected for evaluation of them wound healing potential. Isolation of active component(s) from the active extracts through the bioassay guided fractionation procedures. MATERIAL AND METHODS: In vivo the wound healing activity of the plants was evaluated by linear incision experimental models. The chloroform extract of Echium italicum L. was fractionated by successive chromatographic techniques. Wound healing activity of each fraction was investigated following the bioassay-guided fractionation procedures. Moreover, the tissue samples of isolated compounds were examined histopathologically. The healing potential was comparatively assessed with a reference ointment Madecassol®, which contains 1% extract of Centella asiatica. RESULTS: Significant wound healing activity was observed from the ointment prepared with ethanol extract at 1% concentration. The ethanol root extract treated in groups of animals showed a significant increase (37.38%, 40.97% and 35.29% separately for E. italicum L, Echium vulgare L. and Echium angustifolium Miller) wound tensile strength in the incision wound model. Subfractions showed significant but reduced wound healing activity on in vivo wound models. Shikonin derivatives "Acetylshikonin", "Deoxyshikonin" and "2-methyl-n-butyrylshikonin+Isovalerylshikonin", were isolated and determined as active components of active final subfraction from E. italicum L. roots. The results of histopathological examination supported the outcome of linear incision wound models. CONCLUSION: The experimental study revealed that Echium species display remarkable wound healing activity.


Asunto(s)
Echium/química , Hidrocarburos Cíclicos/uso terapéutico , Componentes Aéreos de las Plantas/química , Extractos Vegetales/farmacología , Cicatrización de Heridas/efectos de los fármacos , Animales , Hidrocarburos Cíclicos/administración & dosificación , Ratones , Estructura Molecular , Extractos Vegetales/química , Turquía
8.
Turk Pediatri Ars ; 50(4): 206-10, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26884689

RESUMEN

AIM: This study aimed to evaluate the demographic, clinical, laboratory properties of patients with macrophage activation syndrome and treatment outcomes. MATERIAL AND METHODS: The data of the patients who were diagnosed with macrophage activation syndrome secondary to systemic juvenile idiopathic arthritis between June 2013-May 2014 were evaluated by screening patient records. RESULTS: Ten patients with macrophage activation syndrome were followed up in one year. The mean age at the time of diagnosis was found to be 7.6±4.5 years. The most common clinical finding at presentation (80%) was increased body temperature. Hepatosplenomegaly was found in half of the patients. The most common hematological finding (90%) was anemia. The mean erythrocyte sedimentation rate was found to be 71.8±36.2 mm/h, whereas it was measured to be lower (31.2±25.2 mm/h) at the time of the diagnosis of macrophage activation syndrome. Increased ferritin level was found in all of our patients (the mean ferritin level was found to be 23 957±15 525 ng/mL). Hypertriglyceridemia was found in nine patients (90%). The mean triglyceride level was found to be 397±332 mg/dL. Systemic steroid treatment was administered to all patients. Cyclosporine A was given to eight patients (80%), canakinumab was given to four patients (40%) and anakinra was given to five patients (50%). Plasmapheresis was performed in two patients. Improvement was found in all patients except for one patient. The patient in whom no improvement was observed showed a chronic course. CONCLUSIONS: The diagnosis of macrophage activation syndrome should be considered in presence of sudden disturbance in general condition, resistant high fever and systemic inflammation findings in children with active rheumatic disease. Complete recovery can be provided with early and efficient treatment in macrophage activation syndrome which develops secondary to systemic juvenil idiopathic arthritis.

9.
Stem Cells ; 32(1): 85-92, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23963711

RESUMEN

The activation of tissue stem cells from their quiescent state represents the initial step in the complex process of organ regeneration and tissue repair. While the identity and location of tissue stem cells are becoming known, how key regulators control the balance of activation and quiescence remains mysterious. The vertebrate hair is an ideal model system where hair cycling between growth and resting phases is precisely regulated by morphogen signaling pathways, but how these events are coordinated to promote orderly signaling in a spatial and temporal manner remains unclear. Here, we show that hair cycle timing depends on regulated stability of signaling substrates by the ubiquitin-proteasome system. Topical application of partial proteasomal inhibitors (PaPIs) inhibits epidermal and dermal proteasome activity throughout the hair cycle. PaPIs prevent the destruction of the key anagen signal ß-catenin, resulting in more rapid hair growth and dramatically shortened telogen. We show that PaPIs induce excess ß-catenin, act similarly to the GSK3ß antagonist LiCl, and antagonize Dickopf-related protein-mediated inhibition of anagen. PaPIs thus represent a novel class of hair growth agents that act through transiently modifying the balance of stem cell activation and quiescence pathways.


Asunto(s)
Folículo Piloso/efectos de los fármacos , Folículo Piloso/crecimiento & desarrollo , Complejo de la Endopetidasa Proteasomal/metabolismo , Inhibidores de Proteasoma/farmacología , beta Catenina/metabolismo , Animales , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/fisiología , Femenino , Folículo Piloso/citología , Folículo Piloso/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Transducción de Señal/efectos de los fármacos , Células Madre/citología , Células Madre/efectos de los fármacos , Células Madre/metabolismo
10.
Biomed Res Int ; 2013: 937918, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23762866

RESUMEN

Microscopic patterns of thirty-four urothelial tumors of the urinary bladder of water buffaloes from the Marmara and Black Sea Regions of Turkey are here described. All the animals grazed on lands rich in bracken fern. Histological diagnosis was assessed using morphological parameters recently suggested for the urinary bladder tumors of cattle. Papillary carcinoma was the most common neoplastic lesion (22/34) observed in this study, and low-grade carcinoma was more common (seventeen cases) than high-grade carcinoma (five cases). Papilloma, papillary urothelial neoplasm of low malignant potential (PUNLMP), and invasive carcinomas were less frequently seen. Carcinoma in situ (CIS) was often detected associated with some papillary and invasive carcinomas. De novo (primary) CIS was rare representing 3% of tumors of this series. A peculiar feature of the most urothelial tumors was the presence in the tumor stroma of immune cells anatomically organized in tertiary lymphoid organs (TLOs). Bovine papillomavirus type-2 (PV-2) E5 oncoprotein was detected by molecular and immunohistochemistry procedures. Early protein, E2, and late protein, L1, were also detected by immunohistochemical studies. Morphological and molecular findings show that BPV-2 infection contributes to the development of urothelial bladder carcinogenesis also in water buffaloes.


Asunto(s)
Papillomavirus Bovino 1/fisiología , Búfalos/virología , Infecciones por Papillomavirus/veterinaria , Vejiga Urinaria/patología , Vejiga Urinaria/virología , Urotelio/patología , Urotelio/virología , Animales , Carcinoma in Situ/patología , Carcinoma in Situ/veterinaria , Carcinoma in Situ/virología , Bovinos , ADN Complementario/genética , ADN Viral/genética , ADN Viral/aislamiento & purificación , Inmunohistoquímica , Linfocitos/patología , Masculino , Infecciones por Papillomavirus/patología , Infecciones por Papillomavirus/virología
11.
Genes Dev ; 27(11): 1217-22, 2013 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-23752588

RESUMEN

The signals regulating stem cell activation during tissue regeneration remain poorly understood. We investigated the baldness associated with mutations in the voltage-gated calcium channel (VGCC) Cav1.2 underlying Timothy syndrome (TS). While hair follicle stem cells express Cav1.2, they lack detectable voltage-dependent calcium currents. Cav1.2(TS) acts in a dominant-negative manner to markedly delay anagen, while L-type channel blockers act through Cav1.2 to induce anagen and overcome the TS phenotype. Cav1.2 regulates production of the bulge-derived BMP inhibitor follistatin-like1 (Fstl1), derepressing stem cell quiescence. Our findings show how channels act in nonexcitable tissues to regulate stem cells and may lead to novel therapeutics for tissue regeneration.


Asunto(s)
Canales de Calcio Tipo L/metabolismo , Señalización del Calcio , Calcio/metabolismo , Folículo Piloso/citología , Células Madre/citología , Células Madre/metabolismo , Animales , Trastorno Autístico , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio Tipo L/genética , Señalización del Calcio/efectos de los fármacos , Proteínas Relacionadas con la Folistatina/biosíntesis , Proteínas Relacionadas con la Folistatina/metabolismo , Síndrome de QT Prolongado/metabolismo , Ratones , Células Madre/efectos de los fármacos , Sindactilia/metabolismo
12.
Cell ; 144(3): 319-21, 2011 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-21295692

RESUMEN

Directed cell migration polarizes the cytoskeleton, allowing the cell to move toward migratory cues. In this issue, Wu et al. (2011) demonstrate that the glycogen synthase kinase 3ß (GSK3ß) controls microtubule architecture and polarized movement of skin stem cells during wound healing in mammals by regulating the microtubule crosslinking protein ACF7.

13.
Science ; 315(5820): 1841-3, 2007 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-17395827

RESUMEN

The long-germ mode of embryogenesis, in which segments arise simultaneously along the anteriorposterior axis, has evolved several times in different lineages of the holometabolous, or fully metamorphosing, insects. Drosophila's long-germ fate map is established largely by the activity of the dipteran-specific Bicoid (Bcd) morphogen gradient, which operates both instructively and permissively to accomplish anterior patterning. By contrast, all nondipteran long-germ insects must achieve anterior patterning independently of bcd. We show that bcd's permissive function is mimicked in the wasp by a maternal repression system in which anterior localization of the wasp ortholog of giant represses anterior expression of the trunk gap genes so that head and thorax can properly form.


Asunto(s)
Tipificación del Cuerpo/genética , Embrión no Mamífero/metabolismo , Regulación del Desarrollo de la Expresión Génica , Proteínas de Insectos/genética , ARN Mensajero Almacenado/metabolismo , Proteínas Represoras/genética , Avispas/embriología , Animales , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Desarrollo Embrionario , Genes de Insecto , Cabeza/embriología , Proteínas de Insectos/metabolismo , Factores de Transcripción de Tipo Kruppel/genética , Factores de Transcripción de Tipo Kruppel/metabolismo , Morfogénesis , Interferencia de ARN , ARN Mensajero Almacenado/genética , Proteínas Represoras/metabolismo , Tórax , Avispas/genética , Avispas/metabolismo
14.
Curr Biol ; 16(1): R29-31, 2006 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-16401416

RESUMEN

The morphogen gradient as a source of embryonic patterning is one of the best accepted concepts in developmental biology. Morphogens can be transcription factors or extracellular signals, but in both cases, they are thought to provide concentration thresholds that position different cell fates within the developing embryo. Several recent papers examine the patterning activities of Drosophila Bicoid, the first known molecular morphogen and reach different conclusions about the patterning power of a single morphogen gradient.


Asunto(s)
Tipificación del Cuerpo , Drosophila/embriología , Proteínas de Homeodominio/metabolismo , Transactivadores/metabolismo , Animales , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Regulación del Desarrollo de la Expresión Génica , Proteínas de Homeodominio/genética , Transactivadores/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
15.
Proc Natl Acad Sci U S A ; 102(14): 4960-5, 2005 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-15793007

RESUMEN

The maternal morphogen Bicoid (Bcd) is distributed in an embryonic gradient that is critical for patterning the anterior-posterior (AP) body plan in Drosophila. Previous work identified several target genes that respond directly to Bcd-dependent activation. Positioning of these targets along the AP axis is thought to be controlled by cis-regulatory modules (CRMs) that contain clusters of Bcd-binding sites of different "strengths." Here we use a combination of Bcd-site cluster analysis and evolutionary conservation to predict Bcd-dependent CRMs. We tested 14 predicted CRMs by in vivo reporter gene assays; 11 show Bcd-dependent activation, which brings the total number of known Bcd target elements to 21. Some CRMs drive expression patterns that are restricted to the most anterior part of the embryo, whereas others extend into middle and posterior regions. However, we do not detect a strong correlation between AP position of target gene expression and the strength of Bcd site clusters alone. Rather, we find that binding sites for other activators, including Hunchback and Caudal correlate with CRM expression in middle and posterior body regions. Also, many Bcd-dependent CRMs contain clusters of sites for the gap protein Kruppel, which may limit the posterior extent of activation by the Bcd gradient. We propose that the key design principle in AP patterning is the differential integration of positive and negative transcriptional information at the level of individual CRMs for each target gene.


Asunto(s)
Drosophila/embriología , Drosophila/genética , Proteínas de Homeodominio/genética , Transactivadores/genética , Animales , Secuencia de Bases , Sitios de Unión/genética , Tipificación del Cuerpo/genética , ADN/genética , ADN/metabolismo , Drosophila/metabolismo , Proteínas de Drosophila , Regulación del Desarrollo de la Expresión Génica , Genes de Insecto , Prueba de Complementación Genética , Proteínas de Homeodominio/metabolismo , Familia de Multigenes , Transactivadores/metabolismo
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