International conference on bioinformatics of genome regulation
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Key words: DNA electrostatics, transcription regulation, genome evolution Motivation and Aim: Genome DNA electrostatics (E.) properties influence its interac- tions with proteins, esp. for transcription regulation (TR). DEPPDB was developed to provide all information on genome DNA physical properties, sequence, and annotation of biological properties of genome elements and whole genomes, organized on taxo- nomical basis. Methods and Algorithms: DEPPDB and its tools [1, 2] were used to carry out the analysis. Results: E. potential (EP) is distributed non-uniformly along DNA and correlates with GC content, strongly depending on the sequence arrangement and its context (flanking regions). Observed RNA polymerase binding frequency to DNA correlates to calculated EP. TR areas have EP peculiarities. Binding sites of transcription factors (TF) of differ- ent protein families in different taxa are located in long areas of high EP. EP distribution on TF protein surface reflects that of binding sites. Promoters in average have high val- ue and heterogeneity of EP profile. Transcription starting sites of prokaryotic genomes are characterized by hundreds of bp of high EP and some peculiarities directly around TSS. This is aimed to protein binding and physical properties formation for transcrip- tion machinery. TSS EP architecture is similar in related taxa. Promoters up-element demonstrates electrostatic nature. E. interact in formation and TR with other physical properties: bending, thermal stability, supercoiling. Curved DNA in promoter regions is preserved and determined by habitat temperature. Mesophiles have different intensity in curvature; (hyper)thermophiles lack it due to life in temperatures above the curvature- relaxing point, rendering it useless in TR. Strongly curved DNA fragments must possess high A+T content (reverse is not true). There is no decrease in size and prominence of electrostatic deep in extremophyles, proving importance of E. and its differential role vs curvature. EP properties of intracellular parasite M. leprae reflect pseudogenization with reduced TR. Conclusion: E. plays universal role in prokaryotic TR, affecting proteins binding. It may influence horizontal gene transfer, TR systems evolution and contribute to genome regu- latory areas high AT content in such diverse domains as Bacteria and Archea. Physical properties affect such fundamental problems as Chargaff’s II rule, genetic code redun- dancy, nonsynonymy of synonymous substitutions etc., approving biophysical bioinfor- matics. Availability: DEPPDB is available at http://deppdb.psn.ru or http://electrodna.psn.ru Acknowledgements: RFBR grants 14-44-03683 and 16-04-01865. References: 1. A.A. Osypov et al (2010) DEPPDB – DNA Electrostatic Potential Properties Database. Electrostatic Properties of Genome DNA, JBCB, 8(3): 413-25 2. A.A. Osypov et al (2012) DEPPDB – DNA Electrostatic Potential Properties Database. Electrostatic Properties of Genome DNA elements, JBCB, 10(2) 1241004. 222 THE TENTH INTERNATIONAL CONFERENCE ON BIOINFORMATICS OF GENOME REGULATION AND STRUCTURE\SYSTEMS BIOLOGY DIFFERENTIAL EXPRESSION IN HELIX LUCORUM STATOCYSTS UNDER MICROGRAVITY CONDITIONS A.A. Osypov 1, 2 *, P. Kolosov 1 , N. Aceyev 1 , E. Chesnokova 1 , M. Roshchin 1 , N. Bal 1 , P. Balaban 1 1 Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia, 2 Institute of Cell Biophysics of RAS, Pushchino, Russia * Corresponding author: aosypov@gmail.com Key words: Helix lucorum, statocysts, gravity reception, transcriptomics, differential expression Motivation and Aim: Helix lucorum snail is a classical model object for studies of the nervous system functions. In order to understand the genome mechanisms of the gravity reception in the snail nervous system we performed a near single-cell transcriptomics analysis of space flight induced differential expression in Helix statocysts. Methods and Algorithms: There were 8 animals in two equal groups of snails - that flied into space (n = 4) and remained on Earth (n = 4), some 13 cells were used per every sample. We performed a full novel transcriptome assembly based on the total mRNA sequenced by means of Ion Proton System. Results: Near 60% of reads per sample were mapped to the assembly, yielding more than 40 significantly differentially expressed (i.e. downregulated by space flight) genes of high accuracy. Most of them relate to the cell reception and different stages of intracellu- lar signaling pathways, including gene expression regulation. Interestingly they were no significantly differently expressed genes if transcripts were mapped to the whole nervous system transcriptome assembly provided by our colleagues, and the overall portion of the mapped reads was less by nearly 20%. Conclusion: The data obtained indicates that genes that are differently expressed are specific to the statocysts themselves and are probably related to gravity reception. Acknowledgements: The work was supported by RSF grant 14-25 00072 223 THE TENTH INTERNATIONAL CONFERENCE ON BIOINFORMATICS OF GENOME REGULATION AND STRUCTURE\SYSTEMS BIOLOGY TOWARDS A NEUROBIOLOGICALLY REASONABLE C. ELEGANS NERVOUS SYSTEM SIMULATION: NEURON, MUSCLE AND SIGNAL PROPAGATION MODELLING A.Yu. Palyanov 1, 2 *, Kh.V. Samoilova 2 1 A.P. Ershov Institute of Informatics Systems, Novosibirsk, Russia 2 Novosibirsk State University, Novosibirsk, Russia * Corresponding author palyanov@iis.nsk.su Key words: C. elegans, nervous system, simulation, ion channels, computational modeling Motivation and Aim: C. elegans with its small 302 neurons nervous system and nearly determined connectome is considered as a first multicellular organism to be reverse- engineered and reproduced in the form of a computer simulation. C. elegans has a spe- cific mechanism of neural signal transmission based on passive propagation since it lacks voltage-gated Na + channels required for typical action potentials. Morphology and electrophysiology of C. elegans neurons allows such signals to travel up to 1 mm or lon- ger distances, although with noticeable delay and fading [1]. Body wall and pharyngeal muscle cells are capable of generating specific calcium-dependent action potentials that are driven by the L- and T-type voltage-gated Ca 2+ and voltage-gated K + channels [2, 3]. Reproduction of at least these mechanisms, including ion channels, neurophysiologic parameters and morphology, is required for a basic neurobiologically reasonable simula- tion which can be further extended with more sophisticated mechanisms. Methods and Algorithms: In this work we used the NEURON simulation environment, which is particularly well-suited to problems that are closely linked to experimental data, especially those that involve cells with complex anatomical and biophysical properties [4]. It provides an ability for construction of custom models of ion channels and other cellular mechanisms via Neuron Model Description Language (NMODL) expanding the standard repertoire, which we employed as well. Results: Using the NEURON programming language HOC and NMODL we have de- veloped a model of a typical C. elegans neuron with parameters known from experi- mental study, which works in good accordance with our calculations [1]. The model of C. elegans pharyngeal muscle with the models of key ion channels was also created and reproduces its time dependence of membrane potential quite well. Conclusion: Proposed models of C. elegans neuron and muscle provide the basis for further development and construction of neural circuits. Acknowledgements: The work was supported by Russian Federation President grant MK- 5714.2015.9 References: 1. A.Yu. Palyanov, A.S. Ratushnyak (2015) Some Details of Signal Propagation in the Nervous System of C. elegans. Russian Journal of Genetics: Applied Research, 5(6): 642-649. 2. S. Gao and M. Zhen. (2011) Action potentials drive body wall muscle contractions in C. elegans. Proc. Natl. Acad. Sci. USA. 108 (6): 2557–2562. 3. B. Shtonda, L. Avery. (2005) CCA-1, EGL-19 and EXP-2 currents shape action potentials in the C. elegans pharynx. J. Exp. Biol. 208: 2177–2190. 4. N.T. Carnevale and M.L. Hines (2006) The NEURON Book, Cambridge, UK: Cambridge University Press. 224 THE TENTH INTERNATIONAL CONFERENCE ON BIOINFORMATICS OF GENOME REGULATION AND STRUCTURE\SYSTEMS BIOLOGY SEARCH FOR FUNCTIONAL NF-KB BINDING SITES VIA META-ANALYSIS OF NGS EXPERIMENTS IN HUMAN CELL LINES N. Panyushev 1, 2 , E. Lomert 1 *, D. Tentler 1 , A. Predeus 2 1 Institute of Cytology RAS, St. Petersburg, Russia 2 Bioinformatics institute, St. Petersburg, Russia * Corresponding author: predeus@gmail.com Key words: transcription factors, ChIP-seq The NF-kB family of transcription factors plays the critical role in inflammation, im- munity, cell proliferation, differentiation and metastasis. NF-kB dimers recognize 9-11 nucleotide sequences called kB sites. There are about 13600 human genes with kB sites in promoter region; however not all of them are transcriptionally active. Thus search for functional kB sites could assist in understanding the basic principles that underlie NF-kB regulation. The combination of chromatin immunoprecipitation (ChIP) and next-generation se- quencing (NGS), namely ChIP-seq, has become a powerful technique to capture poten- tial genomic binding sites of transcription factors, histone modifications and chromatin accessible regions. Using ChIP-seq datasets deposited in the public databases, such as GEO and ENCODE we revealed physical binding sites of p65 (RelA) NF-kB subunit in various human cell lines: MCF-7, HUVEC, HeLa, SGBS and A549. For this purpose, we compared datasets for untreated cells and TNF-alpha-stimulated cells which contain activated p65 (RelA) protein. The effect of binding of NF-kB with predicted kB-sites on gene transcription in cell lines listed above was confirmed by RNA-seq data. The analysis of accessibility of genomic regions to NF-kB binding was carried out using epigenetic ChIP-seq data. Regulatory elements of the genes were distinguished by the histone modifications (H3K4me1, H3K- 4me3, H3K27ac and H3K36me3). The analysis revealed a consistent pattern of the regulation of NF-kB-dependent tran- scription, the correlations of histone modifications and localization and consensus sequence of kB-sites. Regulatory elements (promoters and enhancers) were identi- fied genes via the chromatin context information. Obtained data can be used for experi- mental validation of NF-kb -dependent regulation mechanisms by the binding kB-sites in the regulatory regions. This work is supported by the Russian Science Fund grant (14-50- 00068). 225 THE TENTH INTERNATIONAL CONFERENCE ON BIOINFORMATICS OF GENOME REGULATION AND STRUCTURE\SYSTEMS BIOLOGY NEW INSIGHTS INTO THE REGULATION OF REACTIVE OXYGEN SPECIES BY AUXIN THROUGH GENE EXPRESSION ANALYSIS I.A. Paponov 1, 2 *, V. Budnyk 1 , T. Khodus 1 , M. Paponov 1 , K. Palme 1 1 Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Germany 2 Norwegian Institute of Bioeconomy Research, Norway * Corresponding author: ivan.paponov@bioforsk.no Key works: auxin, reactive oxygen species, ROS, plant growth, environmental stress Motivation and Aim: Plants, unlike animals, cannot move away from environmental stresses. Instead, they capitalise on a wide-ranging potential for growth adjustment in response to stresses. One mechanism believed to underlie this wide-range adjustment is cross-talk between reactive oxygen species (ROS) and the plant hormone auxin. ROS are well known and extensively investigated regulators of auxin activity, acting via oxi- dation, signalling and distribution. However, the manner by which auxin affects ROS is less well understood. Methods: We addressed this question by a combination of microscopy staining data analysis and transcriptomic analysis of gene expression data obtained from publically available experiments that used auxin and ROS treatments. Results: Microscopy staining showed that auxin differentially regulates the level of re- active oxygen species in the roots: it increases hydrogen peroxide levels, as reflected by the fluorescence ratio of ratiometric redox-sensitive GFP (roGFP) and it decreases the cell wall levels of hydroxyl radicals (OH . ). Gene expression analysis of the auxin regulation of all ROS-related genes showed that peroxidases are the best candidates for differential regulation of ROS. General oxidative response genes, which are induced by several ROS, were highly over-representative among the auxin responsive genes. This finding might reflect a combination of ROS induction by auxin and the presence of general oxidative response cis-elements in the promoters of auxin-responsive genes. Thirteen (13) auxin-repressed genes were up-regulated by superoxide, as indicated their up-regulation in a chloroplast superoxide mutant that displays enhanced chloroplastic superoxide levels. Interestingly, 11 of these 13 genes were expressed in chloroplasts, suggesting a novel regulation of chloroplast genes by auxin through specific reduction of the chloroplast superoxide level. Conclusions: Differential induction of ROS by auxin and regulation of auxin activity by ROS results in a positive feedback loop that is pivotal in plant growth adjustment to environmental stress conditions. 226 THE TENTH INTERNATIONAL CONFERENCE ON BIOINFORMATICS OF GENOME REGULATION AND STRUCTURE\SYSTEMS BIOLOGY IDENTIFICATION OF RECOMBINATION SITES IN THE GENOMES OF THE EUROPEAN SUBTYPE OF TICK BORNE ENCEPHALITIS VIRUS A.I. Paramonov 1 *, Yu.P. Dzhioev 1, 2 , I.V. Kozlova 1 1 FGBNU Scientific Center of family health and human reproduction problems, Irkutsk, Russia 2 Irkutsk State Medical University, Institute of Biomedical Technology, Irkutsk, Russia * Corresponding author: paramonov_a.i@mail.ru Key words: recombination, tick borne encephalitis virus, TBEV Motivation and Aim: Tick borne encephalitis virus (TBEV) of the Flaviviridae family is the causative agent in human neuroinfections which often cause disability and death. There are three main subtypes - Far Eastern, Siberian and European (Western). Each subtype has its own habitat; European subtype TBEV has extensive undivided area in Western Europe and mosaic in Asia. Representatives of this serotype circulate in eco- systems significantly different by composition of biocenoses, vectors and hosts. Special attention should be paid to the genetic variation of this subtype, and genetic recombina- tion is one of its leading factors [1, 2, 3]. The aim of this study was to detect potential recombination sites in the genomic sequences of the isolates of European subtype TBEV. Methods and Algorithms: Genomes of 26 strains of European subtype TBEV available in the GenBank data base, as well as 8 strains we sequenced, were used in this work. The phylogenetic test for the presence of recombination was obtained using Splits Tree v4.1, by Neighbor-net method. Statistical test was carried out using the Phi Test for Re- combinations method of Splits Tree software system [4]. Positioning of recombination sites was performed using software methods implemented in the programs package RDP v.4.46 [5]. Results: Phylogenetic network constructed by Neighbor-net has multiple splits indicat- ing the possibility of reticulated evolution and accordingly recombination events at least in some strains. Phi Test for Recombinations showed the presence of recombination in this sequence set with p = 0,008. RDP v4.46 software package found recombination points in strains Joutseno and Absettarov. Interestingly, Joutseno strain contained two independent recombination points. Acknowledgements: The work was supported by Russian Science Foundation grant №14-15-00615. References: 1. Gritsun TS, Nuttall PA, Gould EA. Tick-borne flaviviruses //Adv Virus Res. 2003;61:317 2. I.V. Kozlova et al. Genetic and Biological Properties of Original TBEV Strains Group Circulating in Eastern Siberia //Monograph.«Encephalitis» Edited by S.Tkachev, 283 pages, Publisher: InTech, Pub- lished: January 09, 2013. P. 95-112. 3. Růžek D, Dobler G, Donoso Mantke O. Tick-borne encephalitis: pathogenesis and clinical implica- tions // Travel Med Infect Dis. 2010 Jul;8(4):223-32. 4. Huson DH, Bryant D: Application of phylogenetic networks in evolutionary studies // Mol BiolEvol. 2006, 23.-P. 254-267. 5. Martin DP, Murrell B, Golden M, Khoosal A, & Muhire B (2015) RDP4: Detection and analysis of recombination patterns in virus genomes. Virus Evolution 1: vev003 doi: 10.1093/ve/vev003 227 THE TENTH INTERNATIONAL CONFERENCE ON BIOINFORMATICS OF GENOME REGULATION AND STRUCTURE\SYSTEMS BIOLOGY DARWINIAN GENETIC DRIFT D.V. Parkhomchuk*, A.C. McHardy Department for Computational Biology of Infection Research, Helmholtz Center for Infection Research, Braunschweig, Germany * Corresponding author: parkhomc@googlemail.com Key words: genetic drift, neutral evolution, population variability, Shannon’s entropy Multicellular organisms (including humans) have mutations rates of order of at least few functional mutations per genome per generation. We claim that neither neutral (“non- Darwinian”) drift nor Darwinian selection, via chain of fixations of positive variants are directly applicable to describe genetic variability in a population. The aim is to build a general formalism, which can account for drifting of arbitrarily functional variants explic- itly, including high mutation rates of functional sites. Neutral drift is then a limiting case of such drift. If we let a “perfect” genome, with the best possible variants in all positions, evolve under the high functional mutation rate, it will “degrade” to some average equi- librium fitness, which is less than the fitness of the perfect genome. Then we can study the general properties of a population drifting around the average fitness in equilibrium. The resulting drift is “Darwinian”, because we do not consider neutral variants at all. Instead of neutral evolution, we effectively consider the evolution by compensatory muta- tions (because the average fitness does not change in time). We can calculate the number of unique genomes, which have the equilibrium fitness. This (very large) fundamental number describes the population variability, defining population boundaries in a sequence space. In statistical mechanics the equivalent is a “number of microstates” and in Shan- non’s Information Theory this is a “typical set” size. Correspondingly, if we calculate per- site variability from this number, it turns out to be Shannon’s entropy. The drift displays unusual characteristics, in comparison with models, which are not accounting for high mutation rates in functional sites: population fitness and evolvability is independent from population size; the fraction of positive mutations among random mutations can be high, in general (a trivial consequence of “compensatory” view on mutations accumulation); variants fixations in an equilibrium population play no role for fitness evolution, and can be averaged out. The differences from traditional views stem from the different and incom- patible starting assumptions: we posit that neutrality is an unnecessary oversimplification and it is crucial to consider realistic mutation rates, where the selection force is properly balanced with an equal and opposite stochastic force (for example, but not exclusively, high mutagenesis). When this fundamental balance is not explicitly introduced in a model, such models are critically incomplete and can produce artifactual dependencies. The drift concept is at the core of many bioinformatic models: molecular clock, phylogenetics, coalescent theory and others. Our results suggest that considering the drift as being non- neutral and including compensatory mutations is more realistic and functionally informa- tive in comparison with the neutral drift assumption. It opens a number of bioinformatic challenges, such as to decipher the underlying functionalities of variances in a population, to build consistent models of common polygenic diseases and predispositions, and to im- prove our understanding of genomic complexity evolution, in general. References: 1. A.A. Shadrin, D.V. Parkhomchuk. (2014). Drake’s rule as a consequence of approaching channel ca- pacity. Naturwissenschaften 101, 939–954. 228 THE TENTH INTERNATIONAL CONFERENCE ON BIOINFORMATICS OF GENOME REGULATION AND STRUCTURE\SYSTEMS BIOLOGY IMPACT OF 105-DAY ISOLATION CONDITIONS ON PROTEINS EXPRESSED IN ENDOTHELIAL CELLS, IN THE FRAMEWORK OF THE “MARS-500” PROJECT L.Kh. Pastushkova 1 , D.N. Kashirina 1 , A.S. Kononikhin 1, 3 , A.G. Brzhozovsky 1 , I.V. Dobrokhotov 1 , E.S. Tiys 2 , V.A. Ivanisenko 2 , E.N. Nikolaev 3 , I.M. Larina 1 1 State scientific center of Russian Federation – Institute for biomedicalproblems RAS, Moscow, Russia 2 Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia 3 Emanuel Institute of Biochemical Physics RAS, Moscow, Russia Download 3.91 Kb. Do'stlaringiz bilan baham: |
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