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1.
Plants (Basel) ; 13(17)2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-39273927

RESUMEN

The chickpea plays a significant role in global agriculture and occupies an increasing share in the human diet. The main aim of the research was to develop a model for the prediction of two chickpea productivity traits in the available dataset. Genomic data for accessions were encoded in Artificial Image Objects, and a model for the thousand-seed weight (TSW) and number of seeds per plant (SNpP) prediction was constructed using a Convolutional Neural Network, dictionary learning and sparse coding for feature extraction, and extreme gradient boosting for regression. The model was capable of predicting both traits with an acceptable accuracy of 84-85%. The most important factors for model solution were identified using the dense regression attention maps method. The SNPs important for the SNpP and TSW traits were found in 34 and 49 genes, respectively. Genomic prediction with a constructed model can help breeding programs harness genotypic and phenotypic diversity to more effectively produce varieties with a desired phenotype.

2.
World J Clin Cases ; 11(10): 2226-2236, 2023 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-37122523

RESUMEN

BACKGROUND: An important area of effective control of the coronavirus disease 19 (COVID-19) pandemic is the study of the pathogenic features of severe acute respiratory syndrome coronavirus 2 infection, including those based on assessing the state of the intestinal microbiota and permeability. AIM: To study the clinical features of the new COVID-19 in patients with mild and moderate severity at the stage of hospitalization, to determine the role of hepatobiliary injury, intestinal permeability disorders, and changes in the qualitative and quantitative composition of the microbiota in the development of systemic inflammation in patients with COVID-19. METHODS: The study was performed in 80 patients with COVID-19, with an average age of 45 years, 19 of whom had mild disease, and 61 had moderate disease severity. The scope of the examination included traditional clinical, laboratory, biochemical, instrumental, and radiation studies, as well as original methods for studying microbiota and intestinal permeability. RESULTS: The clinical course of COVID-19 was studied, and the clinical and biochemical features, manifestations of systemic inflammation, and intestinal microbiome changes in patients with mild and moderate severity were identified. Intestinal permeability characteristics against the background of COVID-19 were evaluated by measuring levels of proinflammatory cytokines, insulin, faecal calprotectin, and zonulin. CONCLUSION: This study highlights the role of intestinal permeability and microbiota as the main drivers of gastroenterological manifestations and increased COVID-19 severity.

3.
Int J Mol Sci ; 24(5)2023 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-36902235

RESUMEN

Earlier studies aimed at investigating the metabolism of endogenous nucleoside triphosphates in synchronous cultures of E. coli cells revealed an auto-oscillatory mode of functioning of the pyrimidine and purine nucleotide biosynthesis system, which the authors associated with the dynamics of cell division. Theoretically, this system has an intrinsic oscillatory potential, since the dynamics of its functioning are controlled through feedback mechanisms. The question of whether the nucleotide biosynthesis system has its own oscillatory circuit is still open. To address this issue, an integral mathematical model of pyrimidine biosynthesis was developed, taking into account all experimentally verified negative feedback in the regulation of enzymatic reactions, the data of which were obtained under in vitro conditions. Analysis of the dynamic modes of the model functioning has shown that in the pyrimidine biosynthesis system, both the steady-state and oscillatory functioning modes can be realized under certain sets of kinetic parameters that fit in the physiological boundaries of the investigated metabolic system. It has been demonstrated that the occurrence of the oscillatory nature of metabolite synthesis depended on the ratio of two parameters: the Hill coefficient, hUMP1-the nonlinearity of the UMP effect on the activity of carbamoyl-phosphate synthetase, and the parameter r characterizing the contribution of the noncompetitive mechanism of UTP inhibition to the regulation of the enzymatic reaction of UMP phosphorylation. Thus, it has been theoretically shown that the E. coli pyrimidine biosynthesis system possesses its own oscillatory circuit whose oscillatory potential depends to a significant degree on the mechanism of regulation of UMP kinase activity.


Asunto(s)
Escherichia coli , Pirimidinas , Escherichia coli/metabolismo , Retroalimentación , Nucleótidos , Pirimidinas/metabolismo , Uridina Monofosfato/metabolismo
4.
Plants (Basel) ; 11(23)2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-36501364

RESUMEN

Flowering time is an important target for breeders in developing new varieties adapted to changing conditions. In this work, a new approach is proposed in which the SNP markers influencing time to flowering in mung bean are selected as important features in a random forest model. The genotypic and weather data are encoded in artificial image objects, and a model for flowering time prediction is constructed as a convolutional neural network. The model uses weather data for only a limited time period of 5 days before and 20 days after planting and is capable of predicting the time to flowering with high accuracy. The most important factors for model solution were identified using saliency maps and a Score-CAM method. Our approach can help breeding programs harness genotypic and phenotypic diversity to more effectively produce varieties with a desired flowering time.

5.
J Am Chem Soc ; 144(32): 14590-14606, 2022 08 17.
Artículo en Inglés | MEDLINE | ID: mdl-35939718

RESUMEN

Mass spectrometry (MS) is a convenient, highly sensitive, and reliable method for the analysis of complex mixtures, which is vital for materials science, life sciences fields such as metabolomics and proteomics, and mechanistic research in chemistry. Although it is one of the most powerful methods for individual compound detection, complete signal assignment in complex mixtures is still a great challenge. The unconstrained formula-generating algorithm, covering the entire spectra and revealing components, is a "dream tool" for researchers. We present the framework for efficient MS data interpretation, describing a novel approach for detailed analysis based on deisotoping performed by gradient-boosted decision trees and a neural network that generates molecular formulas from the fine isotopic structure, approaching the long-standing inverse spectral problem. The methods were successfully tested on three examples: fragment ion analysis in protein sequencing for proteomics, analysis of the natural samples for life sciences, and study of the cross-coupling catalytic system for chemistry.


Asunto(s)
Metabolómica , Proteómica , Algoritmos , Mezclas Complejas , Aprendizaje Automático , Espectrometría de Masas/métodos , Metabolómica/métodos
6.
Int J Mol Sci ; 24(1)2022 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-36613583

RESUMEN

Human pluripotent stem cells are promising for a wide range of research and therapeutic purposes. Their maintenance in culture requires the deep control of their pluripotent and clonal status. A non-invasive method for such control involves day-to-day observation of the morphological changes, along with imaging colonies, with the subsequent automatic assessment of colony phenotype using image analysis by machine learning methods. We developed a classifier using a convolutional neural network and applied it to discriminate between images of human embryonic stem cell (hESC) colonies with "good" and "bad" morphological phenotypes associated with a high and low potential for pluripotency and clonality maintenance, respectively. The training dataset included the phase-contrast images of hESC line H9, in which the morphological phenotype of each colony was assessed through visual analysis. The classifier showed a high level of accuracy (89%) in phenotype prediction. By training the classifier on cropped images of various sizes, we showed that the spatial scale of ~144 µm was the most informative in terms of classification quality, which was an intermediate size between the characteristic diameters of a single cell (~15 µm) and the entire colony (~540 µm). We additionally performed a proteomic analysis of several H9 cell samples used in the computational analysis and showed that cells of different phenotypes differentiated at the molecular level. Our results indicated that the proposed approach could be used as an effective method of non-invasive automated analysis to identify undesirable developmental anomalies during the propagation of pluripotent stem cells.


Asunto(s)
Células Madre Pluripotentes , Proteómica , Humanos , Células Madre Pluripotentes/metabolismo , Redes Neurales de la Computación , Células Madre Embrionarias , Control de Calidad
7.
Mol Biol Cell ; 32(21): ar26, 2021 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-34432496

RESUMEN

This work investigates the role of DNA binding by Runt in regulating the sloppy paired 1 (slp1) gene and in particular two distinct cis-regulatory elements that mediate regulation by Runt and other pair-rule transcription factors during Drosophila segmentation. We find that a DNA-binding-defective form of Runt is ineffective at repressing both the distal (DESE) and proximal (PESE) early stripe elements of slp1 and is also compromised for DESE-dependent activation. The function of Runt-binding sites in DESE is further investigated using site-specific transgenesis and quantitative imaging techniques. When DESE is tested as an autonomous enhancer, mutagenesis of the Runt sites results in a clear loss of Runt-dependent repression but has little to no effect on Runt-dependent activation. Notably, mutagenesis of these same sites in the context of a reporter gene construct that also contains the PESE enhancer results in a significant reduction of DESE-dependent activation as well as the loss of repression observed for the autonomous mutant DESE enhancer. These results provide strong evidence that DNA binding by Runt directly contributes to the regulatory interplay of interactions between these two enhancers in the early embryo.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Factores de Transcripción/metabolismo , Animales , Tipificación del Cuerpo/genética , ADN/metabolismo , Proteínas de Unión al ADN/fisiología , Proteínas de Drosophila/fisiología , Drosophila melanogaster/metabolismo , Embrión no Mamífero/metabolismo , Expresión Génica/genética , Regulación del Desarrollo de la Expresión Génica/genética , Genes de Insecto , Proteínas de Homeodominio/metabolismo , Proteínas Nucleares/metabolismo , Secuencias Reguladoras de Ácidos Nucleicos , Factores de Transcripción/fisiología
8.
BMC Plant Biol ; 20(Suppl 1): 202, 2020 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-33050872

RESUMEN

BACKGROUND: Phenology data collected recently for about 300 accessions of Vigna radiata (mungbean) is an invaluable resource for investigation of impacts of climatic factors on plant development. RESULTS: We developed a new mathematical model that describes the dynamic control of time to flowering by daily values of maximal and minimal temperature, precipitation, day length and solar radiation. We obtained model parameters by adaptation to the available experimental data. The models were validated by cross-validation and used to demonstrate that the phenology of adaptive traits, like flowering time, is strongly predicted not only by local environmental factors but also by plant geographic origin and genotype. CONCLUSIONS: Of local environmental factors maximal temperature appeared to be the most critical factor determining how faithfully the model describes the data. The models were applied to forecast time to flowering of accessions grown in Taiwan in future years 2020-2030.


Asunto(s)
Clima , Flores/crecimiento & desarrollo , Modelos Biológicos , Vigna/crecimiento & desarrollo , Adaptación Fisiológica , Genotipo , Factores de Tiempo , Vigna/genética
9.
BMC Plant Biol ; 19(Suppl 2): 94, 2019 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-30890147

RESUMEN

BACKGROUND: Accurate prediction of crop flowering time is required for reaching maximal farm efficiency. Several models developed to accomplish this goal are based on deep knowledge of plant phenology, requiring large investment for every individual crop or new variety. Mathematical modeling can be used to make better use of more shallow data and to extract information from it with higher efficiency. Cultivars of chickpea, Cicer arietanum, are currently being improved by introgressing wild C. reticulatum biodiversity with very different flowering time requirements. More understanding is required for how flowering time will depend on environmental conditions in these cultivars developed by introgression of wild alleles. RESULTS: We built a novel model for flowering time of wild chickpeas collected at 21 different sites in Turkey and grown in 4 distinct environmental conditions over several different years and seasons. We propose a general approach, in which the analytic forms of dependence of flowering time on climatic parameters, their regression coefficients, and a set of predictors are inferred automatically by stochastic minimization of the deviation of the model output from data. By using a combination of Grammatical Evolution and Differential Evolution Entirely Parallel method, we have identified a model that reflects the influence of effects of day length, temperature, humidity and precipitation and has a coefficient of determination of R2=0.97. CONCLUSIONS: We used our model to test two important hypotheses. We propose that chickpea phenology may be strongly predicted by accession geographic origin, as well as local environmental conditions at the site of growth. Indeed, the site of origin-by-growth environment interaction accounts for about 14.7% of variation in time period from sowing to flowering. Secondly, as the adaptation to specific environments is blueprinted in genomes, the effects of genes on flowering time may be conditioned on environmental factors. Genotype-by-environment interaction accounts for about 17.2% of overall variation in flowering time. We also identified several genomic markers associated with different reactions to climatic factor changes. Our methodology is general and can be further applied to extend existing crop models, especially when phenological information is limited.


Asunto(s)
Cicer/fisiología , Cambio Climático , Flores/fisiología , Interacción Gen-Ambiente , Modelos Biológicos , Adaptación Biológica , Genotipo , Geografía , Modelos Estadísticos , Fenotipo , Análisis de Regresión , Turquía
10.
Evol Dev ; 21(3): 157-171, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30756455

RESUMEN

Robustness in development allows for the accumulation of genetically based variation in expression. However, this variation is usually examined in response to large perturbations, and examination of this variation has been limited to being spatial, or quantitative, but because of technical restrictions not both. Here we bridge these gaps by investigating replicated quantitative spatial gene expression using rigorous statistical models, in different genotypes, sexes, and species (Drosophila melanogaster and D. simulans). Using this type of quantitative approach with molecular developmental data allows for comparison among conditions, such as different genetic backgrounds. We apply this approach to the morphogenetic furrow, a wave of differentiation that patterns the developing eye disc. Within the morphogenetic furrow, we focus on four genes, hairy, atonal, hedgehog, and Delta. Hybridization chain reaction quantitatively measures spatial gene expression, co-staining for all four genes simultaneously. We find considerable variation in the spatial expression pattern of these genes in the eye between species, genotypes, and sexes. We also find that there has been evolution of the regulatory relationship between these genes, and that their spatial interrelationships have evolved between species. This variation has no phenotypic effect, and could be buffered by network thresholds or compensation from other genes. Both of these mechanisms could potentially be contributing to long term developmental systems drift.


Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/embriología , Drosophila melanogaster/metabolismo , Drosophila simulans/embriología , Ojo/embriología , Regulación del Desarrollo de la Expresión Génica , Animales , Tipificación del Cuerpo , Drosophila melanogaster/genética , Drosophila simulans/genética , Drosophila simulans/metabolismo , Ojo/metabolismo , Femenino , Genotipo , Larva , Masculino , Modelos Biológicos , Transcriptoma
11.
Dev Biol ; 448(1): 48-58, 2019 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-30629954

RESUMEN

In many biological systems gene expression at mRNA and protein levels is not identical. Rigorous comparison of such differences on a spatio-temporal scale is still not feasible by high-throughput transcriptomic and proteomic analyses of early embryo development. Here, we characterize differences between mRNA and protein expression of Drosophila segmentation genes at the level of individual gene expression domains. We obtained quantitative imaging data on expression of gap genes gt and hb and pair-rule gene eve for Drosophila wild type embryos, Kr null mutants and Kr+/Kr- heterozygotes. To compare mRNA and protein expression we use several criteria including difference in amplitude and positions of expression domains, pattern shape and positional variability. For a number of gene expression domains we show examples where protein expression does not repeat mRNA expression even after a temporal delay. We calculated time delays between eve pattern formation at the level of mRNA and protein for wild type embryos, Kr mutants and Kr+/Kr- heterozygotes. We detect that in wild type embryos, the amplitudes of eve stripes 3 and 7 do not differ significantly at the level of mRNA, however, stripe 3 is higher than stripe 7 at the protein level. We further show that hb mRNA and protein expression in both anterior and posterior domains significantly differs at specific time points. The formation of hb PS4 stripe at the mRNA level proceeds five times faster than at the level of protein. With regard to spatial expression, we show that the offset between posterior gt mRNA and protein domains is much larger in Kr mutants than in wild type embryos and heterozygotes. Finally, we analyze differences in positional variability of eve stripe 7 expression in Kr mutants and Kr+/Kr- heterozygotes at the level of mRNA and protein. These results enable further perspectives to uncover mechanisms underlying discrepancies between mRNA and protein expression in early embryo.


Asunto(s)
Tipificación del Cuerpo/fisiología , Embrión no Mamífero/embriología , Regulación del Desarrollo de la Expresión Génica/fisiología , Genotipo , ARN Mensajero , Animales , Proteínas de Drosophila/biosíntesis , Proteínas de Drosophila/genética , Drosophila melanogaster , Proteínas de Homeodominio/biosíntesis , Proteínas de Homeodominio/genética , Factores de Transcripción de Tipo Kruppel/biosíntesis , Factores de Transcripción de Tipo Kruppel/genética , Microscopía Confocal , ARN Mensajero/genética , ARN Mensajero/metabolismo , Factores de Transcripción/biosíntesis , Factores de Transcripción/genética
12.
Front Genet ; 9: 547, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30524469

RESUMEN

Initiation of flowering moves plants from vegetative to reproductive development. The time when this transition happens (flowering time), an important indicator of productivity, depends on both endogenous and environmental factors. The core genetic regulatory network canalizing the flowering signals to the decision to flower has been studied extensively in the model plant Arabidopsis thaliana and has been shown to preserve its main regulatory blocks in other species. It integrates activation from the FLOWERING LOCUS T (FT) gene or its homologs to the flowering decision expressed as high expression of the meristem identity genes, including AP1. We elaborated a dynamical model of this flowering gene regulatory network and applied it to the previously published expression data from two cultivars of domesticated chickpea (Cicer arietinum), obtained for two photoperiod durations. Due to a large number of free parameters in the model, we used an ensemble approach analyzing the model solutions at many parameter sets that provide equally good fit to data. Testing several alternative hypotheses about regulatory roles of the five FT homologs present in chickpea revealed no preference in segregating individual FT copies as singled-out activators with their own regulatory parameters, thus favoring the hypothesis that the five genes possess similar regulatory properties and provide cumulative activation in the network. The analysis reveals that different levels of activation from AP1 can explain a small difference observed in the expression of the two homologs of the repressor gene TFL1. Finally, the model predicts highly reduced activation between LFY and AP1, thus suggesting that this regulatory block is not conserved in chickpea and needs other mechanisms. Overall, this study provides the first attempt to quantitatively test the flowering time gene network in chickpea based on data-driven modeling.

13.
PLoS One ; 12(9): e0184657, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28898266

RESUMEN

Annotating the genotype-phenotype relationship, and developing a proper quantitative description of the relationship, requires understanding the impact of natural genomic variation on gene expression. We apply a sequence-level model of gap gene expression in the early development of Drosophila to analyze single nucleotide polymorphisms (SNPs) in a panel of natural sequenced D. melanogaster lines. Using a thermodynamic modeling framework, we provide both analytical and computational descriptions of how single-nucleotide variants affect gene expression. The analysis reveals that the sequence variants increase (decrease) gene expression if located within binding sites of repressors (activators). We show that the sign of SNP influence (activation or repression) may change in time and space and elucidate the origin of this change in specific examples. The thermodynamic modeling approach predicts non-local and non-linear effects arising from SNPs, and combinations of SNPs, in individual fly genotypes. Simulation of individual fly genotypes using our model reveals that this non-linearity reduces to almost additive inputs from multiple SNPs. Further, we see signatures of the action of purifying selection in the gap gene regulatory regions. To infer the specific targets of purifying selection, we analyze the patterns of polymorphism in the data at two phenotypic levels: the strengths of binding and expression. We find that combinations of SNPs show evidence of being under selective pressure, while individual SNPs do not. The model predicts that SNPs appear to accumulate in the genotypes of the natural population in a way biased towards small increases in activating action on the expression pattern. Taken together, these results provide a systems-level view of how genetic variation translates to the level of gene regulatory networks via combinatorial SNP effects.


Asunto(s)
Drosophila melanogaster/genética , Redes Reguladoras de Genes , Modelos Genéticos , Polimorfismo de Nucleótido Simple , Animales , Genotipo , Secuencias Reguladoras de Ácidos Nucleicos , Selección Genética
14.
J Bioinform Comput Biol ; 15(2): 1750008, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28351215

RESUMEN

The quantitative characterization of endocytic vesicles in images acquired with microscope is critically important for deciphering of endocytosis mechanisms. Image segmentation is the most important step of quantitative image analysis. In spite of availability of many segmentation methods, the accurate segmentation is challenging when the images are heterogeneous with respect to object shapes and signal intensities what is typical for images of endocytic vesicles. We present a Morphological reconstruction and Contrast mapping segmentation method (MrComas) for the segmentation of the endocytic vesicle population that copes with the heterogeneity in their shape and intensity. The method uses morphological opening and closing by reconstruction in the vicinity of local minima and maxima respectively thus creating the strong contrast between their basins of attraction. As a consequence, the intensity is flattened within the objects and their edges are enhanced. The method accurately recovered quantitative characteristics of synthetic images that preserve characteristic features of the endocytic vesicle population. In benchmarks and quantitative comparisons with two other popular segmentation methods, namely manual thresholding and Squash plugin, MrComas shows the best segmentation results on real biological images of EGFR (Epidermal Growth Factor Receptor) endocytosis. As a proof of feasibility, the method was applied to quantify the dynamical behavior of Early Endosomal Autoantigen 1 (EEA1)-positive endosome subpopulations during EGF-stimulated endocytosis.


Asunto(s)
Algoritmos , Biología Computacional/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Vesículas Transportadoras , Endocitosis/fisiología , Endosomas/metabolismo , Receptores ErbB/metabolismo , Células HeLa , Humanos , Proteínas de Transporte Vesicular/metabolismo
15.
BMC Evol Biol ; 17(Suppl 1): 4, 2017 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-28251865

RESUMEN

BACKGROUND: Cis-regulatory sequences are often composed of many low-affinity transcription factor binding sites (TFBSs). Determining the evolutionary and functional importance of regulatory sequence composition is impeded without a detailed knowledge of the genotype-phenotype map. RESULTS: We simulate the evolution of regulatory sequences involved in Drosophila melanogaster embryo segmentation during early development. Natural selection evaluates gene expression dynamics produced by a computational model of the developmental network. We observe a dramatic decrease in the total number of transcription factor binding sites through the course of evolution. Despite a decrease in average sequence binding energies through time, the regulatory sequences tend towards organisations containing increased high affinity transcription factor binding sites. Additionally, the binding energies of separate sequence segments demonstrate ubiquitous mutual correlations through time. Fewer than 10% of initial TFBSs are maintained throughout the entire simulation, deemed 'core' sites. These sites have increased functional importance as assessed under wild-type conditions and their binding energy distributions are highly conserved. Furthermore, TFBSs within close proximity of core sites exhibit increased longevity, reflecting functional regulatory interactions with core sites. CONCLUSION: In response to elevated mutational pressure, evolution tends to sample regulatory sequence organisations with fewer, albeit on average, stronger functional transcription factor binding sites. These organisations are also shaped by the regulatory interactions among core binding sites with sites in their local vicinity.


Asunto(s)
Simulación por Computador , Drosophila melanogaster/embriología , Drosophila melanogaster/genética , Evolución Molecular , Mutación , Secuencias Reguladoras de Ácidos Nucleicos , Animales , Sitios de Unión , Proteínas de Drosophila/genética , Unión Proteica , Selección Genética , Factores de Transcripción/metabolismo
16.
BMC Genomics ; 16 Suppl 13: S7, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26694511

RESUMEN

BACKGROUND: The statistical thermodynamics based approach provides a promising framework for construction of the genotype-phenotype map in many biological systems. Among important aspects of a good model connecting the DNA sequence information with that of a molecular phenotype (gene expression) is the selection of regulatory interactions and relevant transcription factor bindings sites. As the model may predict different levels of the functional importance of specific binding sites in different genomic and regulatory contexts, it is essential to formulate and study such models under different modeling assumptions. RESULTS: We elaborate a two-layer model for the Drosophila gap gene network and include in the model a combined set of transcription factor binding sites and concentration dependent regulatory interaction between gap genes hunchback and Kruppel. We show that the new variants of the model are more consistent in terms of gene expression predictions for various genetic constructs in comparison to previous work. We quantify the functional importance of binding sites by calculating their impact on gene expression in the model and calculate how these impacts correlate across all sites under different modeling assumptions. CONCLUSIONS: The assumption about the dual interaction between hb and Kr leads to the most consistent modeling results, but, on the other hand, may obscure existence of indirect interactions between binding sites in regulatory regions of distinct genes. The analysis confirms the previously formulated regulation concept of many weak binding sites working in concert. The model predicts a more or less uniform distribution of functionally important binding sites over the sets of experimentally characterized regulatory modules and other open chromatin domains.


Asunto(s)
Drosophila/genética , Drosophila/metabolismo , Redes Reguladoras de Genes , Animales , Sitios de Unión/genética , Biología Computacional , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Regulación del Desarrollo de la Expresión Génica , Modelos Genéticos , Factores de Transcripción/metabolismo
17.
BMC Genomics ; 16 Suppl 8: S9, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26111206

RESUMEN

The genetic structure of human populations is extraordinarily complex and of fundamental importance to studies of anthropology, evolution, and medicine. As increasingly many individuals are of mixed origin, there is an unmet need for tools that can infer multiple origins. Misclassification of such individuals can lead to incorrect and costly misinterpretations of genomic data, primarily in disease studies and drug trials. We present an advanced tool to infer ancestry that can identify the biogeographic origins of highly mixed individuals. reAdmix can incorporate individual's knowledge of ancestors (e.g. having some ancestors from Turkey or a Scottish grandmother). reAdmix is an online tool available at http://chcb.saban-chla.usc.edu/reAdmix/.


Asunto(s)
Evolución Biológica , Biología Computacional , Etnicidad/genética , Genética Médica/métodos , Animales , Humanos , Programas Informáticos
18.
J Bioinform Comput Biol ; 12(2): 1441002, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24712529

RESUMEN

In this paper, a specific aspect of the prediction problem is considered: high predictive power is understood as a possibility to reproduce correct behavior of model solutions at predefined values of a subset of parameters. The problem is discussed in the context of a specific mathematical model, the gene circuit model for segmentation gap gene system in early Drosophila development. A shortcoming of the model is that it cannot be used for predicting the system behavior in mutants when fitted to wild type (WT) data. In order to answer a question whether experimental data contain enough information for the correct prediction we introduce two measures of predictive power. The first measure reveals the biologically substantiated low sensitivity of the model to parameters that are responsible for correct reconstruction of expression patterns in mutants, while the second one takes into account their correlation with the other parameters. It is demonstrated that the model solution, obtained by fitting to gene expression data in WT and Kr⁻ mutants simultaneously, and exhibiting the high predictive power, is characterized by much higher values of both measures than those fitted to WT data alone. This result leads us to the conclusion that information contained in WT data is insufficient to reliably estimate the large number of model parameters and provide predictions of mutants.


Asunto(s)
Proteínas de Drosophila/genética , Drosophila/crecimiento & desarrollo , Drosophila/genética , Regulación del Desarrollo de la Expresión Génica/genética , Redes Reguladoras de Genes/genética , Modelos Genéticos , Modelos Estadísticos , Algoritmos , Animales , Simulación por Computador , Interpretación Estadística de Datos
19.
PLoS One ; 9(3): e91502, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24643004

RESUMEN

As an RNA virus, hepatitis C virus (HCV) is able to rapidly acquire drug resistance, and for this reason the design of effective anti-HCV drugs is a real challenge. The HCV subgenomic replicon-containing cells are widely used for experimental studies of the HCV genome replication mechanisms, for drug testing in vitro and in studies of HCV drug resistance. The NS3/4A protease is essential for virus replication and, therefore, it is one of the most attractive targets for developing specific antiviral agents against HCV. We have developed a stochastic model of subgenomic HCV replicon replication, in which the emergence and selection of drug resistant mutant viral RNAs in replicon cells is taken into account. Incorporation into the model of key NS3 protease mutations leading to resistance to BILN-2061 (A156T, D168V, R155Q), VX-950 (A156S, A156T, T54A) and SCH 503034 (A156T, A156S, T54A) inhibitors allows us to describe the long term dynamics of the viral RNA suppression for various inhibitor concentrations. We theoretically showed that the observable difference between the viral RNA kinetics for different inhibitor concentrations can be explained by differences in the replication rate and inhibitor sensitivity of the mutant RNAs. The pre-existing mutants of the NS3 protease contribute more significantly to appearance of new resistant mutants during treatment with inhibitors than wild-type replicon. The model can be used to interpret the results of anti-HCV drug testing on replicon systems, as well as to estimate the efficacy of potential drugs and predict optimal schemes of their usage.


Asunto(s)
Farmacorresistencia Viral/genética , Hepacivirus/genética , Modelos Estadísticos , ARN Viral/genética , Replicón , Proteínas no Estructurales Virales/genética , Replicación Viral/genética , Antivirales/farmacología , Carbamatos/farmacología , Farmacorresistencia Viral/efectos de los fármacos , Hepacivirus/efectos de los fármacos , Compuestos Macrocíclicos/farmacología , Oligopéptidos/farmacología , Polimorfismo de Nucleótido Simple , Prolina/análogos & derivados , Prolina/farmacología , Inhibidores de Proteasas/farmacología , Quinolinas/farmacología , Procesos Estocásticos , Tiazoles/farmacología
20.
BMC Genomics ; 15 Suppl 12: S6, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25564104

RESUMEN

BACKGROUND: The detailed analysis of transcriptional regulation is crucially important for understanding biological processes. The gap gene network in Drosophila attracts large interest among researches studying mechanisms of transcriptional regulation. It implements the most upstream regulatory layer of the segmentation gene network. The knowledge of molecular mechanisms involved in gap gene regulation is far less complete than that of genetics of the system. Mathematical modeling goes beyond insights gained by genetics and molecular approaches. It allows us to reconstruct wild-type gene expression patterns in silico, infer underlying regulatory mechanism and prove its sufficiency. RESULTS: We developed a new model that provides a dynamical description of gap gene regulatory systems, using detailed DNA-based information, as well as spatial transcription factor concentration data at varying time points. We showed that this model correctly reproduces gap gene expression patterns in wild type embryos and is able to predict gap expression patterns in Kr mutants and four reporter constructs. We used four-fold cross validation test and fitting to random dataset to validate the model and proof its sufficiency in data description. The identifiability analysis showed that most model parameters are well identifiable. We reconstructed the gap gene network topology and studied the impact of individual transcription factor binding sites on the model output. We measured this impact by calculating the site regulatory weight as a normalized difference between the residual sum of squares error for the set of all annotated sites and for the set with the site of interest excluded. CONCLUSIONS: The reconstructed topology of the gap gene network is in agreement with previous modeling results and data from literature. We showed that 1) the regulatory weights of transcription factor binding sites show very weak correlation with their PWM score; 2) sites with low regulatory weight are important for the model output; 3) functional important sites are not exclusively located in cis-regulatory elements, but are rather dispersed through regulatory region. It is of importance that some of the sites with high functional impact in hb, Kr and kni regulatory regions coincide with strong sites annotated and verified in Dnase I footprint assays.


Asunto(s)
Redes Reguladoras de Genes , Modelos Genéticos , Animales , Sitios de Unión , Drosophila/embriología , Drosophila/genética , Drosophila/metabolismo , Mutación , Análisis de Secuencia de ADN , Factores de Transcripción/metabolismo
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