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1.
Cell Rep ; 43(5): 114145, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38669141

RESUMO

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.


Assuntos
Células Matadoras Naturais , Leucemia Mieloide Aguda , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Humanos , Leucemia Mieloide Aguda/terapia , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/imunologia , Animais , Camundongos , Receptores de Antígenos Quiméricos/metabolismo , Receptores de Antígenos Quiméricos/imunologia , Redes Reguladoras de Genes , Células-Tronco Hematopoéticas/metabolismo , Linhagem Celular Tumoral , Medicina de Precisão/métodos , Terapia Baseada em Transplante de Células e Tecidos/métodos
2.
Genes Dev ; 32(9-10): 723-736, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29764918

RESUMO

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.


Assuntos
Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/embriologia , Drosophila melanogaster/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Transativadores/genética , Transativadores/metabolismo , Motivos de Aminoácidos , Animais , Padronização Corporal/genética , Drosophila melanogaster/metabolismo , Desenvolvimento Embrionário/efeitos dos fármacos , Desenvolvimento Embrionário/genética , Elementos Facilitadores Genéticos/genética , Ligação Proteica
3.
Eur Urol Focus ; 4(1): 128-138, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28753805

RESUMO

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.


Assuntos
Microbiota/fisiologia , Prostatite/microbiologia , Incontinência Urinária/microbiologia , Sistema Urinário/microbiologia , Doenças Urológicas/dietoterapia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bactérias/genética , Biomarcadores/metabolismo , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Prebióticos/efeitos adversos , Probióticos/uso terapêutico , RNA Ribossômico 16S/genética , Doenças Urológicas/microbiologia , Adulto Jovem
4.
Rheumatol Int ; 38(1): 67-74, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28828621

RESUMO

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.


Assuntos
Dor Abdominal/etiologia , Amiloidose/etiologia , Colchicina/uso terapêutico , Febre Familiar do Mediterrâneo/complicações , Pirina/genética , Moduladores de Tubulina/uso terapêutico , Dor Abdominal/genética , Adolescente , Amiloidose/genética , Criança , Pré-Escolar , Febre Familiar do Mediterrâneo/diagnóstico , Febre Familiar do Mediterrâneo/tratamento farmacológico , Febre Familiar do Mediterrâneo/genética , Feminino , Genótipo , Humanos , Lactente , Masculino , Mutação , Resultado do Tratamento
5.
Nucl Med Commun ; 39(2): 131-139, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29257007

RESUMO

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.


Assuntos
Apoptose/efeitos da radiação , Radioisótopos do Iodo/efeitos adversos , Rim/metabolismo , Rim/efeitos da radiação , Animais , Caspases/metabolismo , Proliferação de Células/efeitos da radiação , Quebras de DNA/efeitos da radiação , Feminino , Imuno-Histoquímica , Rim/patologia , Ratos , Ratos Wistar , Fatores de Tempo
6.
Drug Res (Stuttg) ; 67(2): 103-110, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27824430

RESUMO

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.


Assuntos
Antioxidantes/farmacologia , Dieta da Carga de Carboidratos/efeitos adversos , Frutose/efeitos adversos , Fígado/efeitos dos fármacos , Óxido Nítrico Sintase Tipo III/metabolismo , Hepatopatia Gordurosa não Alcoólica/induzido quimicamente , Hepatopatia Gordurosa não Alcoólica/enzimologia , Estilbenos/farmacologia , Animais , Antioxidantes/administração & dosagem , Biomarcadores/sangue , Peso Corporal/efeitos dos fármacos , Feminino , Frutose/administração & dosagem , Xarope de Milho Rico em Frutose/administração & dosagem , Xarope de Milho Rico em Frutose/efeitos adversos , Insulina/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Interleucina-1beta/metabolismo , Fígado/enzimologia , Fígado/patologia , Masculino , Hepatopatia Gordurosa não Alcoólica/patologia , Ratos , Ratos Wistar , Receptor de Insulina/metabolismo , Resveratrol , Transdução de Sinais , Estilbenos/administração & dosagem , Triglicerídeos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
7.
J Ethnopharmacol ; 185: 370-6, 2016 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-26947902

RESUMO

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.


Assuntos
Echium/química , Hidrocarbonetos Cíclicos/uso terapêutico , Componentes Aéreos da Planta/química , Extratos Vegetais/farmacologia , Cicatrização/efeitos dos fármacos , Animais , Hidrocarbonetos Cíclicos/administração & dosagem , Camundongos , Estrutura Molecular , Extratos Vegetais/química , Turquia
8.
Turk Pediatri Ars ; 50(4): 206-10, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26884689

RESUMO

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.
Artigo em Inglês | MEDLINE | ID: mdl-23963711

RESUMO

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.


Assuntos
Folículo Piloso/efeitos dos fármacos , Folículo Piloso/crescimento & desenvolvimento , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , beta Catenina/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Feminino , Folículo Piloso/citologia , Folículo Piloso/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Transdução de Sinais/efeitos dos fármacos , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo
10.
Biomed Res Int ; 2013: 937918, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23762866

RESUMO

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.


Assuntos
Papillomavirus Bovino 1/fisiologia , Búfalos/virologia , Infecções por Papillomavirus/veterinária , Bexiga Urinária/patologia , Bexiga Urinária/virologia , Urotélio/patologia , Urotélio/virologia , Animais , Carcinoma in Situ/patologia , Carcinoma in Situ/veterinária , Carcinoma in Situ/virologia , Bovinos , DNA Complementar/genética , DNA Viral/genética , DNA Viral/isolamento & purificação , Imuno-Histoquímica , Linfócitos/patologia , Masculino , Infecções por Papillomavirus/patologia , Infecções por Papillomavirus/virologia
11.
Genes Dev ; 27(11): 1217-22, 2013 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-23752588

RESUMO

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.


Assuntos
Canais de Cálcio Tipo L/metabolismo , Sinalização do Cálcio , Cálcio/metabolismo , Folículo Piloso/citologia , Células-Tronco/citologia , Células-Tronco/metabolismo , Animais , Transtorno Autístico , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo L/genética , Sinalização do Cálcio/efeitos dos fármacos , Proteínas Relacionadas à Folistatina/biossíntese , Proteínas Relacionadas à Folistatina/metabolismo , Síndrome do QT Longo/metabolismo , Camundongos , Células-Tronco/efeitos dos fármacos , Sindactilia/metabolismo
12.
Cell ; 144(3): 319-21, 2011 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-21295692

RESUMO

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.
Artigo em Inglês | MEDLINE | ID: mdl-17395827

RESUMO

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.


Assuntos
Padronização Corporal/genética , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Insetos/genética , RNA Mensageiro Estocado/metabolismo , Proteínas Repressoras/genética , Vespas/embriologia , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Desenvolvimento Embrionário , Genes de Insetos , Cabeça/embriologia , Proteínas de Insetos/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Morfogênese , Interferência de RNA , RNA Mensageiro Estocado/genética , Proteínas Repressoras/metabolismo , Tórax , Vespas/genética , Vespas/metabolismo
14.
Curr Biol ; 16(1): R29-31, 2006 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-16401416

RESUMO

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.


Assuntos
Padronização Corporal , Drosophila/embriologia , Proteínas de Homeodomínio/metabolismo , Transativadores/metabolismo , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/genética , Transativadores/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
15.
Proc Natl Acad Sci U S A ; 102(14): 4960-5, 2005 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-15793007

RESUMO

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.


Assuntos
Drosophila/embriologia , Drosophila/genética , Proteínas de Homeodomínio/genética , Transativadores/genética , Animais , Sequência de Bases , Sítios de Ligação/genética , Padronização Corporal/genética , DNA/genética , DNA/metabolismo , Drosophila/metabolismo , Proteínas de Drosophila , Regulação da Expressão Gênica no Desenvolvimento , Genes de Insetos , Teste de Complementação Genética , Proteínas de Homeodomínio/metabolismo , Família Multigênica , Transativadores/metabolismo
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