RESUMO
Local adaptation is critical for species persistence in the face of rapid environmental change, but its genetic basis is not well understood. Growing the model plant Arabidopsis thaliana in field experiments in four sites across the species' native range, we identified candidate loci for local adaptation from a genome-wide association study of lifetime fitness in geographically diverse accessions. Fitness-associated loci exhibited both geographic and climatic signatures of local adaptation. Relative to genomic controls, high-fitness alleles were generally distributed closer to the site where they increased fitness, occupying specific and distinct climate spaces. Independent loci with different molecular functions contributed most strongly to fitness variation in each site. Independent local adaptation by distinct genetic mechanisms may facilitate a flexible evolutionary response to changing environment across a species range.
Assuntos
Adaptação Fisiológica , Arabidopsis/genética , Arabidopsis/fisiologia , Clima , Aptidão Genética , Genoma de Planta , Polimorfismo de Nucleotídeo Único , Aclimatação , Alelos , Europa (Continente) , Genes de Plantas , Loci Gênicos , Estudo de Associação Genômica Ampla , Geografia , Ligação Proteica , Seleção Genética , Temperatura , Fatores de Transcrição/metabolismoRESUMO
OBJECTIVES: Mathematical models are useful for studying vascular and avascular tumours, because these allow for more logical experimental design and provide valuable insights into the underlying mechanisms of their growth and development. The processes of avascular tumour growth and the development of capillary networks through tumour-induced angiogenesis have already been extensively investigated, albeit separately. Despite the clinical significance of vascular tumours, few studies have combined these approaches to develop a single comprehensive growth and development model. MATERIALS AND METHODS: We develop a continuum-based mathematical model of vascular tumour growth. In the model, angiogenesis is initiated through the release of angiogenic growth factors (AGFs) by cells in the hypoxic regions of the tumour. The nutrient concentration within the tumour reflects the influence of capillary growth and invasion induced by AGF. RESULTS AND CONCLUSIONS: Parametric and sensitivity studies were performed to evaluate the influence of different model parameters on tumour growth and to identify the parameters with the most influence, which include the rates of proliferation, apoptosis and necrosis, as well as the diffusion of sprout tips and the size of the region affected by angiogenesis. An optimization was performed for values of the model parameters that resulted in the best agreement with published experimental data. The resulting model solution matched the experimental data with a high degree of correlation (r = 0.85).
Assuntos
Modelos Biológicos , Neovascularização Patológica/patologia , Neoplasias Vasculares/irrigação sanguínea , Neoplasias Vasculares/patologia , Apoptose , Proliferação de Células , Humanos , Neovascularização Patológica/metabolismo , Fatores de Crescimento do Endotélio Vascular/metabolismo , Neoplasias Vasculares/metabolismoRESUMO
We are now reaching the stage at which specific genetic factors with known physiological effects can be tied directly and quantitatively to variation in phenology. With such a mechanistic understanding, scientists can better predict phenological responses to novel seasonal climates. Using the widespread model species Arabidopsis thaliana, we explore how variation in different genetic pathways can be linked to phenology and life-history variation across geographical regions and seasons. We show that the expression of phenological traits including flowering depends critically on the growth season, and we outline an integrated life-history approach to phenology in which the timing of later life-history events can be contingent on the environmental cues regulating earlier life stages. As flowering time in many plants is determined by the integration of multiple environmentally sensitive gene pathways, the novel combinations of important seasonal cues in projected future climates will alter how phenology responds to variation in the flowering time gene network with important consequences for plant life history. We discuss how phenology models in other systems--both natural and agricultural--could employ a similar framework to explore the potential contribution of genetic variation to the physiological integration of cues determining phenology.
Assuntos
Adaptação Fisiológica/fisiologia , Arabidopsis/crescimento & desenvolvimento , Mudança Climática , Flores/crescimento & desenvolvimento , Adaptação Fisiológica/genética , Arabidopsis/genética , Arabidopsis/fisiologia , Flores/genética , Flores/fisiologia , Fotoperíodo , Estações do Ano , TemperaturaRESUMO
Adaptive immunity has been defined, principally through studies of avian and mammalian species, as the ability to mount specific immune responses to a virtually unlimited variety of antigens. A key feature of an adaptive immune system is the ability to remember previous encounters with antigens and to achieve a more rapid, heightened response on secondary encounter. Adaptive immune systems featuring an enormous anticipatory receptor diversity and specific memory have been defined only in vertebrates. Surprisingly, the adaptive immune systems in jawless and jawed vertebrates employ very different types of antigen receptors. This evolutionary inventiveness suggests that adaptive immunity provided additional fitness value over the previously existing innate immune mechanisms.
Assuntos
Imunidade Adaptativa , Evolução Biológica , Doenças Transmissíveis/imunologia , Interações Hospedeiro-Patógeno/imunologia , Vertebrados/imunologia , Animais , Antígenos/imunologia , Linfócitos B/imunologia , Doenças Transmissíveis/microbiologia , Memória Imunológica , Ativação Linfocitária , Receptores de Antígenos/imunologia , Linfócitos T/imunologiaRESUMO
Overexpression of the TCL1 gene family plays a role in the onset of T-cell leukemias in mice and in humans. The Tcl1 gene is tightly regulated during early embryogenesis in which it participates in embryonic stem (ES)-cells proliferation and during lymphoid differentiation. Here, we provide evidences that Tcl1 is also important in mouse hair follicle (HF) and skin homeostasis. We found that Tcl1(-/-) adult mice exhibit hair loss, leading to alopecia with extensive skin lesions. By analysing Tcl1 expression in the wild-type (wt) skin through different stages of hair differentiation, we observe high levels in the secondary hair germ (HG) cells and hair bulges, during early anagen and catagen-telogen transition phases. The loss of Tcl1 does not result in apparent skin morphological defects during embryonic development and at birth, but its absence causes a reduction of proliferation in anagen HFs. Importantly, we show the that absence of Tcl1 induces a significant loss of the stem-cell marker CD34 (but not alpha6-integrin) expression in the bulge cells, which is necessary to maintain stem-cell characteristics. Therefore, our findings indicate that Tcl1 gene(s) might have important roles in hair formation, by its involvement in cycling and self-renewal of transient amplifying (TA) and stem-cell (SC) populations.
Assuntos
Antígenos CD34/análise , Folículo Piloso/embriologia , Proteínas Proto-Oncogênicas/fisiologia , Células-Tronco/fisiologia , Alopecia/etiologia , Animais , Diferenciação Celular , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-akt/fisiologia , Pele/patologiaRESUMO
Triggering receptor expressed on myeloid cells-2 (TREM-2) is an innate immune receptor that initiates cellular activation upon ligation. In this study, we examined the interaction of TREM-2 with Neisseria gonorrhoeae using murine TREM-2A, as it has been reported to recognize bacterial ligands. Using a whole-bacteria enzyme-linked immunosorbent assay (ELISA), TREM-2A bound to all six strains in variable degrees. Far-western blots of gonococcal outer membranes revealed TREM-2A binding to lipooligosaccharide (LOS) and opacity (Opa) protein, with predominant binding to LOS. Binding of TREM-2A to LOS was confirmed by ELISA and surface plasmon resonance. O-deacylation of the lipid A significantly reduced binding. Flow cytometry and reporter cell assays showed that gonococci bound to TREM-2A-transfected cells and induced transmembrane signaling. In humans, TREM-2 was constitutively expressed by genitourinary and fallopian tube epithelial cells, both of which are primary targets of gonococcal invasion. Ligation of TREM-2 by LOS induced interleukin-6 production in HeLa cervical carcinoma cells. To our knowledge, this is the first report of the expression of human TREM-2 by cells deriving from a non-myeloid lineage. We conclude that gonococci can interact with TREM-2 receptors through binding to LOS and Opa protein and initiate cell signaling and cytokine production.
Assuntos
Tubas Uterinas/imunologia , Lipopolissacarídeos/imunologia , Neisseria gonorrhoeae/imunologia , Receptores Imunológicos/imunologia , Animais , Proteínas da Membrana Bacteriana Externa/imunologia , Linhagem Celular , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Tubas Uterinas/metabolismo , Tubas Uterinas/microbiologia , Feminino , Humanos , Interleucina-6/biossíntese , Camundongos , Ligação Proteica/imunologia , Receptores Imunológicos/biossíntese , Transdução de SinaisRESUMO
Two experiments were conducted to examine the effects of depriving dairy cows of the ability to feed and lie down for short periods, on behaviour and production. In experiment 1, cows were deprived by confining them in pairs in a pen for 2 or 4 h, and they more frequently exhibited behaviour likely to suggest discomfort - leg stamping, repositioning themselves, shifting their weight between legs and butting. After deprivation, the cows deprived for 2 h made up their lost feeding time within 24 h, but cows deprived for 4 h did not restore their feeding time within the 41-h period of observation. Lying time was not restored in either treatment within the 41-h period. Milk yield was not affected by the treatment. However, in experiment 2, when cows were deprived of feeding and lying for 4 h, during which time their hooves were trimmed (which is likely to be a painful and stressful procedure and result in some discomfort for a period post-trimming) the evidence suggested that milk yield was reduced by approximately 2 l/day for 3 days, with corresponding increases during the subsequent 2 days. Walking speed on returning to the herd was the same as before the treatment. In summary, temporary deprivation of feeding and lying for 2 and 4 h/day induced behaviours that were indicative of discomfort and frustration but had no negative effect on milk production, except when 4 h of deprivation was accompanied by foot trimming.
RESUMO
Cows are often temporarily deprived of the opportunity to lie down while waiting for veterinary or reproductive procedures. Sixty cows were deprived of the opportunity to lie down for 0, 2, or 4 h by confining them in pairs in a small indoor pen. Behavior was recorded during deprivation and for 40 h afterwards. In the first 2 and 4 h of the experiment, cows that were not deprived chose to lie down for 70 and 142 min, respectively. When cows were discouraged from lying, they regularly stomped their legs, repositioned themselves, but never lay down. In the 4-h treatment, both stomping and repositioning increased after the first hour. Butting and weight shifting (displacing weight from one side of the body to the other) increased during deprivation, indicating restlessness. Cows deprived for 4 h sniffed and rubbed their heads against the housing more than cows deprived for 0 or 2 h. Time spent feeding and standing without ruminating increased with the duration of deprivation, especially during the early stages; standing ruminating also increased in the final stages. After deprivation, feeding time decreased, which compensated for the increase during deprivation. By 40 h after deprivation, the lying-deprived cows had recovered approximately 40% of their lost lying time. Milk yield was not affected by lying deprivation. It is concluded that cows experience discomfort during short periods of lying deprivation, after which they recover some, but not all, of the lost lying time by rescheduling feeding and standing time.
Assuntos
Comportamento Animal/fisiologia , Bovinos/fisiologia , Indústria de Laticínios/métodos , Lactação/fisiologia , Animais , Feminino , Fatores de Tempo , Gravação em VídeoRESUMO
PROBLEM: Safety climate refers to the degree to which employees believe true priority is given to organizational safety performance, and its measurement is thought to provide an "early warning" of potential safety system failure(s). However, researchers have struggled over the last 25 years to find empirical evidence to demonstrate actual links between safety climate and safety performance. METHOD: A safety climate measure was distributed to manufacturing employees at the beginning of a behavioral safety initiative and redistributed one year later. RESULTS: Multiple regression analysis demonstrated that perceptions of the importance of safety training were predictive of actual levels of safety behavior. The results also demonstrate that the magnitude of change in perceptual safety climate scores will not necessarily match actual changes (r=0.56, n.s.) in employee's safety behavior. DISCUSSION: This study obtained empirical links between safety climate scores and actual safety behavior. Confirming and contradicting findings within the extant safety climate literature, the results strongly suggest that the hypothesized climate-behavior-accident path is not as clear cut as commonly assumed. SUMMARY: A statistical link between safety climate perceptions and safety behavior will be obtained when sufficient behavioral data is collected. IMPACT ON INDUSTRY: The study further supports the use of safety climate measures as useful diagnostic tools in ascertaining employee's perceptions of the way that safety is being operationalized.
Assuntos
Acidentes de Trabalho/prevenção & controle , Comportamentos Relacionados com a Saúde , Saúde Ocupacional , Local de Trabalho/organização & administração , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cultura Organizacional , Projetos Piloto , Inquéritos e QuestionáriosRESUMO
We describe a neutron radiography technique that can be used to map the distribution of 3He impurities in liquid 4He, providing direct and quantitative access to underlying transport processes. Images reflecting finite normal- and superfluid-component 4He velocity fields are presented.
RESUMO
We have measured the cosmic ray spectrum above 10(17.2) eV using the two air-fluorescence detectors of the High Resolution Fly's Eye observatory operating in monocular mode. We describe the detector, phototube, and atmospheric calibrations, as well as the analysis techniques for the two detectors. We fit the spectrum to a model consisting of galactic and extragalactic sources.
RESUMO
The gene for one of the activating members of the paired Ig-like receptor family, Pira6, was isolated from a genomic library and sequenced. The first of 9 exons in the approximately 8.2 kb Pira6 gene encodes the 5' untranslated region, the translation initiation site, and approximately half of the signal sequence. The second exon encodes the rest of the signal sequence, exons 3-8 each encode a single Ig-like extracellular domain, and exon 9 encodes the transmembrane region, cytoplasmic tail and 3' UTR with four polyadenylation signals and six mRNA instability sequences. A soluble form of PIR-A6 may be generated by alternative splicing. The exonic sequences account for approximately 42% of the Pira6 gene and approximately 34% for the single inhibitory Pirb gene, thus defining Pira and Pirb as genes with relatively short intronic sequences. Extensive sequence homology was found between Pira6 and Pirb from approximately 2 kb upstream of the ATG initiation site to the beginning of intron 8. The Pir genes appear to be distributed in three regions of the proximal end of chromosome 7 based on the present data and an analysis of currently available mouse genomic sequence databases. One region contains a single Pir gene which is almost identical to Pira6, and the other two contain multiple Pir genes in opposite transcriptional orientations. Potential binding sites for hemopoiesis-specific and ubiquitous transcription factors were identified upstream of the Pira6 transcription start sites that reside within the initiator consensus sequence motif. These results provide important clues to the coordinate regulation observed for PIR-A and PIR-B expression during hematopoiesis.
Assuntos
Receptores Imunológicos/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Camundongos , Dados de Sequência Molecular , Receptores Imunológicos/imunologia , Análise de Sequência de DNA , Sítio de Iniciação de TranscriçãoRESUMO
Neisseria gonorrhoeae has a repertoire of up to 11 opacity-associated (Opa) proteins that are adhesins. Most Opa proteins adhere to CEACAM antigens and when CEACAM molecules are present on the surface of transfected epithelial cells their binding by Opa is thought to induce invasion of these cells by gonococci. In this study, we investigated whether several malignant epithelial cell lines, normal cervical and fallopian tube epithelial cell cultures, as well as normal fallopian tube tissue express several of the CEACAM molecules, and whether gonococci use these molecules for adherence and invasion of these female genital epithelial cells. A primary cervical cell culture and metastatic cervical cell line ME180 both expressed CEACAM as shown by whole cell ELISA and flow cytometry, and increased the surface expression of total CEACAM during incubation with Opa+ gonococci. Opa+ gonococci both adhered to and invaded these cells; CEACAM-specific monoclonal antibody (MAb) partially abolished this interaction. Two primary fallopian epithelial tube cell cultures, a primary cervical cell culture and two malignant cell lines, HEC-1-B and HeLa, did not express CEACAM nor was CEACAM mRNA present. No evidence of either intracellular or secreted extracellular CEACAM was found with HEC-1-B and HeLa cells. Opa+ gonococci both adhered to and invaded CEACAM non-expressing cells; however, Opa+ gonococcal association with these non-expressing cell lines could not be inhibited with CEACAM-specific MAb. These data show that CEACAM is not always expressed on female genital epithelial cells and is not essential for gonococcal adherence and invasion. However, when CEACAM is expressed, Opa+ gonococci exploit it for the adherence to and invasion of these cells.
Assuntos
Antígenos CD/metabolismo , Antígenos de Diferenciação/metabolismo , Aderência Bacteriana , Colo do Útero/microbiologia , Células Epiteliais/microbiologia , Tubas Uterinas/microbiologia , Neisseria gonorrhoeae/fisiologia , Antígenos de Bactérias/metabolismo , Antígenos CD/genética , Antígenos de Diferenciação/genética , Moléculas de Adesão Celular , Linhagem Celular , Células Cultivadas , Colo do Útero/citologia , Colo do Útero/metabolismo , Ensaio de Imunoadsorção Enzimática , Células Epiteliais/metabolismo , Tubas Uterinas/citologia , Tubas Uterinas/metabolismo , Feminino , Citometria de Fluxo , Humanos , Células Tumorais CultivadasRESUMO
The potential of the paired Ig-like receptors of activating (PIR-A) and inhibitory (PIR-B) types for modifying an IgE antibody-mediated allergic response was evaluated in mouse bone marrow-derived mast cells. Although mast cells produced both PIR-A and PIR-B, PIR-B was found to be preferentially expressed on the cell surface, where it was constitutively tyrosine phosphorylated and associated with intracellular SHP-1 protein tyrosine phosphatase. PIR-B coligation with the IgE receptor (FcepsilonRI) inhibited IgE-mediated mast cell activation and release of serotonin. Surprisingly, the inhibitory activity of PIR-B was unimpaired in SHP-1-deficient mast cells. A third functional tyrosine-based inhibitory motif, one that fails to bind the SHP-1, SHP-2, and SHIP phosphatases, was identified in parallel studies of FcepsilonRI-bearing rat basophilic leukemia (RBL) cells transfected with constructs having mutations in the PIR-B cytoplasmic region. These results define the preferential expression of the PIR-B molecules on mast cells and an inhibitory potential that can be mediated via a SHP-1-independent pathway.
Assuntos
Imunoglobulina E/imunologia , Mastócitos/imunologia , Receptores Imunológicos/imunologia , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/imunologia , Cálcio/metabolismo , Células Cultivadas , Citoplasma/metabolismo , Expressão Gênica , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/imunologia , Mastócitos/citologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Fosforilação , Receptores de IgE/imunologia , Receptores Imunológicos/genética , Serotonina/metabolismo , Baço/citologia , Tirosina/metabolismoRESUMO
The VpreB/lambda5 surrogate L chain complex is an essential component of the pre-B cell receptor, the expression of which serves as an important checkpoint in B cell development. Surrogate L chains also may serve as components of murine pro-B cell receptors whose function is unknown. We have produced two new mAbs, R3 and R5, that recognize a different VpreB epitope than the one recognized by the previously described VP245 anti-mouse VpreB Ab. These Abs were used to confirm the expression of surrogate L chains on wild-type pro-B and pre-B cell lines. Although undetectable on the cell surface, VpreB was found to be normally expressed within B lineage cells of lambda5-deficient mice. Nevertheless, VpreB expression was extinguished at the B cell stage of differentiation in these mice. The normal pattern of VpreB expression in lambda5-deficient mice excludes an essential role for pro-B and pre-B cell receptors in VpreB regulation.
Assuntos
Linfócitos B/imunologia , Cadeias lambda de Imunoglobulina/genética , Glicoproteínas de Membrana/metabolismo , Animais , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , Diferenciação Celular , Linhagem da Célula , Epitopos/imunologia , Cadeias Leves de Imunoglobulina , Cadeias Leves Substitutas da Imunoglobulina , Glicoproteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Ratos , Ratos Sprague-Dawley , Células-Tronco/imunologiaRESUMO
Investigation of human genome sequences with a consensus sequence derived from receptors for the Fc region of Igs (FcR) led to the identification of a subfamily of five Ig superfamily members that we term the Fc receptor homologs (FcRHs). The closely linked FcRH genes are located in a chromosome 1q21 region in the midst of previously recognized FcR genes. This report focuses on the FcRH1, FcRH2, and FcRH3 members of this gene family. Their cDNAs encode type I transmembrane glycoproteins with 3-6 Ig-like extracellular domains and cytoplasmic domains containing consensus immunoreceptor tyrosine-based activating and/or inhibitory signaling motifs. The five FcRH genes are structurally related, and their protein products share 28-60% extracellular identity with each other. They also share 15-31% identity with their closest FcR relatives. The FcRH genes are expressed primarily, although not exclusively, by mature B lineage cells. Their conserved structural features, patterns of cellular expression, and the inhibitory and activating signaling potential of their transmembrane protein products suggest that the members of this FcRH multigene family may serve important regulatory roles in normal and neoplastic B cell development.
Assuntos
Linfócitos B/metabolismo , Fragmentos Fc das Imunoglobulinas/metabolismo , Família Multigênica , Isoformas de Proteínas/genética , Receptores Fc/genética , Sequência de Aminoácidos , Northern Blotting , Mapeamento Cromossômico , Cromossomos Humanos Par 1/genética , Cromossomos Humanos Par 19/genética , Sequência Consenso , DNA Complementar/genética , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/metabolismo , Humanos , Dados de Sequência Molecular , Proteínas de Neoplasias/genética , Especificidade de Órgãos , Filogenia , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/química , Receptores Fc/biossíntese , Receptores Fc/química , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
The biological functions of immunoglobulin (Ig)A antibodies depend primarily on their interaction with cell surface receptors. Four IgA receptors are presently characterized. The FcalphaRI (CD89) expressed by myeloid cells selectively binds IgA1 and IgA2 antibodies, whereas the poly-IgR, Fcalpha/muR, and asialoglycoprotein receptors bind other ligands in addition to IgA. IgA binding by mesangial cells, epithelial cells, and proliferating lymphocytes is also well documented, but the nature of the IgA receptors on these cells remains elusive. A monoclonal antibody (A24) is described here that specifically blocks IgA binding to epithelial and B lymphocyte cell lines. Both the A24 antibody and IgA1 myelomas bind a cell surface protein that is identified as the transferrin receptor (CD71). The transferrin receptor selectively binds IgA1 antibodies, monomeric better than polymeric forms, and the IgA1 binding is inhibitable by transferrin. Transferrin receptor expression is upregulated on cultured mesangial cells as well as on glomerular mesangial cells in patients with IgA nephropathy. The characterization of transferrin receptor as a novel IgA1 receptor on renal mesangial cells suggests its potential involvement in the pathogenesis of IgA nephropathy.
Assuntos
Mesângio Glomerular/metabolismo , Glomerulonefrite por IGA/metabolismo , Receptores Fc/metabolismo , Receptores da Transferrina/metabolismo , Animais , Anticorpos Monoclonais/metabolismo , Imunofluorescência , Humanos , Imuno-Histoquímica , Masculino , Ratos , Regulação para CimaRESUMO
The avian B cell differentiation Ag chB1 is a membrane glycoprotein relative of the mammalian B cell differentiation Ag CD72. Unlike CD72, this C-type lectin is expressed in relatively high levels on immature B cells in the bursa of Fabricius and is down-regulated on mature B cells in the periphery. An immunoreceptor tyrosine-based inhibitory motif in the chB1 cytoplasmic tail suggests a potential regulatory role in intrabursal B cell development. To gain further insight into the selective expression and function of chB1, we determined the genomic organization of chB1 and examined the mechanism of its transcriptional regulation. The 8-exon chB1 gene proved to have very similar organization to that of mouse CD72, further supporting the idea that chB1 is a CD72 relative. As for mouse CD72, the chB1 promoter region lacks a TATA box but contains a conserved initiator element. The 131-bp region (-161 to -30) proximal to the transcriptional start site, which contains a potential early B cell factor binding site, is essential for the B lineage stage-specific transcription of chB1, whereas PU.1 and B cell-specific activator protein/Pax5 have been shown to play important roles in CD72 promoter activity and cell-type specificity. This analysis suggests that differences in transcriptional regulation of these phylogenetically related genes may determine the differences in expression pattern and, therefore, the function of avian chB1 and mammalian CD72 during B cell development.
Assuntos
Antígenos de Diferenciação de Linfócitos B/química , Antígenos de Diferenciação de Linfócitos B/genética , Linfócitos B/citologia , Linfócitos B/imunologia , Éxons , Íntrons , Transcrição Gênica/imunologia , Regiões 5' não Traduzidas/metabolismo , Sequência de Aminoácidos , Animais , Antígenos CD/química , Antígenos CD/genética , Antígenos de Diferenciação de Linfócitos B/biossíntese , Sequência de Bases , Sítios de Ligação/genética , Sítios de Ligação/imunologia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Linhagem Celular , Linhagem Celular Transformada , Galinhas , Regulação da Expressão Gênica/imunologia , Lectinas/química , Lectinas/genética , Lectinas Tipo C , Dados de Sequência Molecular , Regiões Promotoras Genéticas/imunologia , Análise de Sequência de DNA , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Interferon-alpha and -beta inhibit the interleukin-7-mediated growth and survival of T and B lymphoid progenitors via an unknown, STAT1-independent pathway. Gene expression profile analysis of interferon-beta-treated progenitor B cells revealed enhanced Daxx expression, with concomitant Daxx protein increase and nuclear body translocation. The interferon effects included downregulation of cell cycle regulating genes and cell cycle arrest, followed by Bcl-2 downregulation and apoptosis. Daxx antisense oligonucleotides rescued the interferon-treated pro-B cells from growth arrest and apoptosis in parallel with the reduction of nuclear Daxx. These findings implicate the gene repressor function of Daxx in interferon-induced apoptosis of lymphoid progenitors.