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5,000
Human housekeeping genes are compact
q-bio.GN
We identify a set of 575 human genes that are expressed in all conditions tested in a publicly available database of microarray results. Based on this common occurrence, the set is expected to be rich in "housekeeping" genes, showing constitutive expression in all tissues. We compare selected aspects of their genomic s...
biology
5,001
A covariance kernel for proteins
q-bio.GN
We propose a new kernel for biological sequences which borrows ideas and techniques from information theory and data compression. This kernel can be used in combination with any kernel method, in particular Support Vector Machines for protein classification. By incorporating prior biological assumptions on the properti...
biology
5,002
Random model for RNA interference yields scale free network
q-bio.GN
We introduce a random bit-string model of post-transcriptional genetic regulation based on sequence matching. The model spontaneously yields a scale free network with power law scaling with $ \gamma=-1$ and also exhibits log-periodic behaviour. The in-degree distribution is much narrower, and exhibits a pronounced peak...
biology
5,003
Computational identification of transcription factor binding sites by functional analysis of sets of genes sharing overrepresented upstream motifs
q-bio.GN
BACKGROUND: Transcriptional regulation is a key mechanism in the functioning of the cell, and is mostly effected through transcription factors binding to specific recognition motifs located upstream of the coding region of the regulated gene. The computational identification of such motifs is made easier by the fact th...
biology
5,004
MAVID: Constrained ancestral alignment of multiple sequences
q-bio.GN
We describe a new global multiple alignment program capable of aligning a large number of genomic regions. Our progressive alignment approach incorporates the following ideas: maximum-likelihood inference of ancestral sequences, automatic guide-tree construction, protein based anchoring of ab-initio gene predictions, a...
biology
5,005
Relevance Vector Machines for classifying points and regions in biological sequences
q-bio.GN
The Relevance Vector Machine (RVM) is a recently developed machine learning framework capable of building simple models from large sets of candidate features. Here, we describe a protocol for using the RVM to explore very large numbers of candidate features, and a family of models which apply the power of the RVM to cl...
biology
5,006
What can we learn from noncoding regions of similarity between genomes?
q-bio.GN
Background: In addition to known protein-coding genes, large amount of apparently non-coding sequence are conserved between the human and mouse genomes. It seems reasonable to assume that these conserved regions are more likely to contain functional elements than less-conserved portions of the genome. Here we used a mo...
biology
5,007
Clone-array pooled shotgun mapping and sequencing: design and analysis of experiments
q-bio.GN
This paper studies sequencing and mapping methods that rely solely on pooling and shotgun sequencing of clones. First, we scrutinize and improve the recently proposed Clone-Array Pooled Shotgun Sequencing (CAPSS) method, which delivers a BAC-linked assembly of a whole genome sequence. Secondly, we introduce a novel phy...
biology
5,008
Genetic Paralog Analysis and Simulations
q-bio.GN
Using Monte Carlo methods, we simulated the effects of bias in generation and elimination of paralogs on the size distribution of paralog groups. It was found that the function describing the decay of the number of paralog groups with their size depends on the ratio between the probability of duplications of genes and ...
biology
5,009
RNA Binding Density on X-chromosome Differing from that on 22 Autosomes in Human
q-bio.GN
To test whether X-chromosome has unique genomic characteristics, X-chromosome and 22 autosomes were compared for RNA binding density. Nucleotide sequences on the chromosomes were divided into 50kb per segment that was recoded as a set of frequency values of 7-nucleotide (7nt) strings using all possible 7nt strings (47=...
biology
5,010
Solution of the Quasispecies Model for an Arbitrary Gene Network
q-bio.GN
In this paper, we study the equilibrium behavior of Eigen's quasispecies equations for an arbitrary gene network. We consider a genome consisting of $ N $ genes, so that each gene sequence $ \sigma $ may be written as $ \sigma = \sigma_1 \sigma_2 ... \sigma_N $. We assume a single fitness peak (SFP) model for each gene...
biology
5,011
A Machine Learning Strategy to Identity Exonic Splice Enhancers in Human Protein-coding Sequence
q-bio.GN
Background: Exonic splice enhancers are sequences embedded within exons which promote and regulate the splicing of the transcript in which they are located. A class of exonic splice enhancers are the SR proteins, which are thought to mediate interactions between splicing factors bound to the 5' and 3' splice sites. Met...
biology
5,012
Statistical analysis of the distribution of amino acids in Borrelia burgdorferi genome under different genetic codes
q-bio.GN
The genetic code is considered to be universal. In order to test if some statistical properties of the coding bacterial genome were due to inherent properties of the genetic code, we compared the autocorrelation function, the scaling properties and the maximum entropy of the distribution of distances of amino acids in ...
biology
5,013
Statistical analysis of Gene and Intergenic DNA Sequences
q-bio.GN
Much of the on-going statistical analysis of DNA sequences is focused on the estimation of characteristics of coding and non-coding regions that would possibly allow discrimination of these regions. In the current approach, we concentrate specifically on genes and intergenic regions. To estimate the level and type of c...
biology
5,014
Statistical properties of DNA sequences revisited: the role of inverse bilateral symmetry in bacterial chromosomes
q-bio.GN
Herein it is shown that in order to study the statistical properties of DNA sequences in bacterial chromosomes it suffices to consider only one half of the chromosome because they are similar to its corresponding complementary sequence in the other half. This is due to the inverse bilateral symmetry of bacterial chromo...
biology
5,015
Monte Carlo Simulation and Statistical Analysis of Genetic Information Coding
q-bio.GN
The rules that specify how the information contained in DNA codes amino acids, is called "the genetic code". Using a simplified version of the Penna nodel, we are using computer simulations to investigate the importance of the genetic code and the number of amino acids in Nature on population dynamics. We find that the...
biology
5,016
SUMO Substrates and Sites Prediction Combining Pattern Recognition and Phylogenetic Conservation
q-bio.GN
Small Ubiquitin-related modifier (SUMO) proteins are widely expressed in eukaryotic cells, which are reversibly coupled to their substrates by motif recognition, called sumoylation. Two interesting questions are 1) how many potential SUMO substrates may be included in mammalian proteomes, such as human and mouse, 2) an...
biology
5,017
Needed for completion of the human genome: hypothesis driven experiments and biologically realistic mathematical models
q-bio.GN
With the sponsorship of ``Fundacio La Caixa'' we met in Barcelona, November 21st and 22nd, to analyze the reasons why, after the completion of the human genome sequence, the identification all protein coding genes and their variants remains a distant goal. Here we report on our discussions and summarize some of the maj...
biology
5,018
Gene splice sites correlate with nucleosome positions
q-bio.GN
Gene sequences in the vicinity of splice sites are found to possess dinucleotide periodicities, especially RR and YY, with the period close to the pitch of nucleosome DNA. This confirms previously reported finding about preferential positioning of splice junctions within the nucleosomes. The RR and YY dinucleotides osc...
biology
5,019
Systematic identification of abundant A-to-I editing sites in the human transcriptome
q-bio.GN
RNA editing by members of the double-stranded RNA-specific ADAR family leads to site-specific conversion of adenosine to inosine (A-to-I) in precursor messenger RNAs. Editing by ADARs is believed to occur in all metazoa, and is essential for mammalian development. Currently, only a limited number of human ADAR substrat...
biology
5,020
Divergence and Shannon information in genomes
q-bio.GN
Shannon information (SI) and its special case, divergence, are defined for a DNA sequence in terms of probabilities of chemical words in the sequence and are computed for a set of complete genomes highly diverse in length and composition. We find the following: SI (but not divergence) is inversely proportional to seque...
biology
5,021
Is abundant A-to-I RNA editing primate-specific?
q-bio.GN
A-To-I RNA editing is common to all eukaryotes, associated with various neurological functions. Recently, A-to-I editing was found to occur abundantly in the human transcriptome. Here we show that the frequency of A-to-I editing in humans is at least an order of magnitude higher as that of mouse, rat, chicken or fly. T...
biology
5,022
A New Simulated Annealing Algorithm for the Multiple Sequence Alignment Problem: The approach of Polymers in a Random Media
q-bio.GN
We proposed a probabilistic algorithm to solve the Multiple Sequence Alignment problem. The algorithm is a Simulated Annealing (SA) that exploits the representation of the Multiple Alignment between $D$ sequences as a directed polymer in $D$ dimensions. Within this representation we can easily track the evolution in th...
biology
5,023
Identification and Measurement of Neighbor Dependent Nucleotide Substitution Processes
q-bio.GN
The presence of neighbor dependencies generated a specific pattern of dinucleotide frequencies in all organisms. Especially, the CpG-methylation-deamination process is the predominant substitution process in vertebrates and needs to be incorporated into a more realistic model for nucleotide substitutions. Based on a ge...
biology
5,024
Substantial regional variation in substitution rates in the human genome: importance of GC content, gene density and telomere-specific effects
q-bio.GN
This study presents the first global, 1 Mbp level analysis of patterns of nucleotide substitutions along the human lineage. The study is based on the analysis of a large amount of repetitive elements deposited into the human genome since the mammalian radiation, yielding a number of results that would have been difficu...
biology
5,025
Molecular Phylogenetic Analyses and Real Life Data
q-bio.GN
In molecular phylogeny, relationships among organisms are reconstructed using DNA or protein sequences and are displayed as trees. A linear increase in the number of sequences results in an exponential increase of possible trees. Thus, inferring trees from molecular data was shown to be NP-hard. This causes problems, i...
biology
5,026
Global divergence of microbial genome sequences mediated by propagating fronts
q-bio.GN
We model the competition between recombination and point mutation in microbial genomes, and present evidence for two distinct phases, one uniform, the other genetically diverse. Depending on the specifics of homologous recombination, we find that global sequence divergence can be mediated by fronts propagating along th...
biology
5,027
Statistical analysis of simple repeats in the human genome
q-bio.GN
The human genome contains repetitive DNA at different level of sequence length, number and dispersion. Highly repetitive DNA is particularly rich in homo-- and di--nucleotide repeats, while middle repetitive DNA is rich of families of interspersed, mobile elements hundreds of base pairs (bp) long, among which the Alu f...
biology
5,028
Evolutionarily conserved human targets of adenosine to inosine RNA editing
q-bio.GN
A-to-I RNA editing by ADARs is a post-transcriptional mechanism for expanding the proteomic repertoire. Genetic recoding by editing was so far observed for only a few mammalian RNAs that are predominantly expressed in nervous tissues. However, as these editing targets fail to explain the broad and severe phenotypes of ...
biology
5,029
Mimivirus Gene Promoters Exhibit an Unprecedented Conservation among all Eukaryotes
q-bio.GN
The initial analysis of the recently sequenced genome of Acanthamoeba polyphaga Mimivirus, the largest known double-stranded DNA virus, predicted a proteome of size and complexity more akin to small parasitic bacteria than to other nucleo-cytoplasmic large DNA viruses, and identified numerous functions never before des...
biology
5,030
Ab initio identification of putative human transcription factor binding sites by comparative genomics
q-bio.GN
We discuss a simple and powerful approach for the ab initio identification of cis-regulatory motifs involved in transcriptional regulation. The method we present integrates several elements: human-mouse comparison, statistical analysis of genomic sequences and the concept of coregulation. We apply it to a complete scan...
biology
5,031
On the Complexity of Several Haplotyping Problems
q-bio.GN
In this paper we present a collection of results pertaining to haplotyping. The first set of results concerns the combinatorial problem of reconstructing haplotypes from incomplete and/or imperfectly sequenced haplotype data. More specifically, we show that an interesting, restricted case of Minimum Error Correction (M...
biology
5,032
Gene & Genome Duplication in Acanthamoeba Polyphaga Mimivirus
q-bio.GN
Gene duplication is key to molecular evolution in all three domains of life and may be the first step in the emergence of new gene function. It is a well recognized feature in large DNA viruses, but has not been studied extensively in the largest known virus to date, the recently discovered Acanthamoeba Polyphaga Mimiv...
biology
5,033
Identity Elements of Archaeal tRNA
q-bio.GN
Features unique to a transfer-RNA are recognized by the corresponding tRNA-synthetase. Keeping this in view we isolate the discriminating features of all archaeal tRNA. These are our identity elements. Further, we investigate tRNA-characteristics that delineate the different orders of archaea.
biology
5,034
Evidence for abundant transcription of non-coding regions in the Saccharomyces cerevisiae genome
q-bio.GN
Background: Recent studies in a growing number of organisms have yielded accumulating evidence that a significant portion of the non-coding region in the genome is transcribed. We address this issue in the yeast Saccharomyces cerevisiae. Results: Taking into account the absence of a significantly large yeast EST data...
biology
5,035
Is there any sense in antisense editing?
q-bio.GN
A number of recent studies have hypothesized that sense-antisense RNA transcript pairs create dsRNA duplexes that undergo extensive A-to-I RNA editing. Here we studied human and mouse genomic antisense regions, and found that the editing level in these areas is negligible. This observation puts in question the scope of...
biology
5,036
Introns Restructure tRNA Genes of Archaea
q-bio.GN
This paper has been withdrawn by the author.
biology
5,037
Conspiracy in bacterial genomes
q-bio.GN
The rank ordered distribution of the codon usage frequencies for 123 bacteriae is best fitted by a three parameters function that is the sum of a constant, an exponential and a linear term in the rank n. The parameters depend (two parabolically) from the total GC content. The rank ordered distribution of the amino acid...
biology
5,038
Positioning Crenarchaeal tRNA-Introns
q-bio.GN
We precisely position a noncanonical intron in the odd second copy of tRNAAsp(GTC) gene in the newly sequenced crenarchaea S.acidocaldarius. The uniform assortment of some features from normal aspartate tDNA and some from those corresponding to non-standard amino acids conduce us to conjecture it to be a novel tRNA gen...
biology
5,039
Universality of Long-Range Correlations in Expansion-Randomization Systems
q-bio.GN
We study the stochastic dynamics of sequences evolving by single site mutations, segmental duplications, deletions, and random insertions. These processes are relevant for the evolution of genomic DNA. They define a universality class of non-equilibrium 1D expansion-randomization systems with generic stationary long-ra...
biology
5,040
Domesticated P elements in the Drosophila montium species subgroup have a new function related to a DNA binding property
q-bio.GN
Molecular domestication of a transposable element is defined as its functional recruitment by the host genome. To date, two independent events of molecular domestication of the P transposable element have been described: in the Drosophila obscura species group and in the Drosophila montium species subgroup. These P neo...
biology
5,041
Statistical Indicators of Collective Behavior and Functional Clusters in Gene Networks of Yeast
q-bio.GN
We analyze gene expression time-series data of yeast S. cerevisiae measured along two full cell-cycles. We quantify these data by using q-exponentials, gene expression ranking and a temporal mean-variance analysis. We construct gene interaction networks based on correlation coefficients and study the formation of the c...
biology
5,042
The protein map of Synechococcus sp. PCC 7942 - the first overlook
q-bio.GN
The unicellular cyanobacterium Synechococcus PCC 7942 has been used as a model organism for studies of prokaryotic circadian rhythms, carbon-concentrating mechanisms, response to a variety of nutrient and environmental stresses, and cell division. This paper presents the results of the first proteomic exploratory study...
biology
5,043
Non-extensive Trends in the Size Distribution of Coding and Non-coding DNA Sequences in the Human Genome
q-bio.GN
We study the primary DNA structure of four of the most completely sequenced human chromosomes (including chromosome 19 which is the most dense in coding), using Non-extensive Statistics. We show that the exponents governing the decay of the coding size distributions vary between $5.2 \le r \le 5.7$ for the short scales...
biology
5,044
tRNA-isoleucine-tryptophan Composite Gene
q-bio.GN
Transfer-RNA genes in archaea often have introns intervening between exon sequences. The structural motif at the boundary between exon and intron is the bulge-helix-bulge. Computational investigations of these boundary structures in H. marismortui lead us to propose that tRNA-isoleucine and tRNA-tryptophan genes are co...
biology
5,045
Quantitative modeling and data analysis of SELEX experiments
q-bio.GN
SELEX (Systematic Evolution of Ligands by Exponential Enrichment) is an experimental procedure that allows extracting, from an initially random pool of DNA, those oligomers with high affinity for a given DNA-binding protein. We address what is a suitable experimental and computational procedure to infer parameters of t...
biology
5,046
Cloning, expression and purification of the general stress protein Yhbo from Escherichia coli
q-bio.GN
We cloned, expressed and purified the Escherichia coli yhbO gene product, which is homolog to the Bacillus subtilis general stress protein 18 (the yfkM gene product), the Pyrococcus furiosus intracellular protease PfpI, and the human Parkinson disease protein DJ-1. The gene coding for YhbO was generated by amplifying t...
biology
5,047
Regularization Strategies for Hyperplane Classifiers: Application to Cancer Classification with Gene Expression Data
q-bio.GN
Linear discrimination, from the point of view of numerical linear algebra, can be treated as solving an ill-posed system of linear equations. In order to generate a solution that is robust in the presence of noise, these problems require regularization. Here, we examine the ill-posedness involved in the linear discrimi...
biology
5,048
Qualitative Assessment of Gene Expression in Affymetrix Genechip Arrays
q-bio.GN
Affymetrix Genechip microarrays are used widely to determine the simultaneous expression of genes in a given biological paradigm. Probes on the Genechip array are atomic entities which by definition are randomly distributed across the array and in turn govern the gene expression. In the present study, we make several i...
biology
5,049
Effects of Growth on Dinitrogen on the Transcriptome and Predicted Proteome of Nostoc PCC 7120
q-bio.GN
Upon growth on dinitrogen, the filamentous cyanobacterium Nostoc PCC 7120 initiates metabolic and morphological changes. We analyzed the expression of 1249 genes from major metabolic categories under nitrogen fixing and non-nitrogen fixing growth. The expression data were correlated with potential target secondary stru...
biology
5,050
Microarray Data Management. An Enterprise Information Approach: Implementations and Challenges
q-bio.GN
The extraction of information form high-throughput experiments is a key aspect of modern biology. Early in the development of microarray technology, researchers recognized that the size of the datasets and the limitations of both computational and visualization techniques restricted their ability to find the biological...
biology
5,051
Gene Function Classification Using Bayesian Models with Hierarchy-Based Priors
q-bio.GN
We investigate the application of hierarchical classification schemes to the annotation of gene function based on several characteristics of protein sequences including phylogenic descriptors, sequence based attributes, and predicted secondary structure. We discuss three Bayesian models and compare their performance in...
biology
5,052
Large-scale Oscillation of Structure-Related DNA Sequence Features in Human Chromosome 21
q-bio.GN
Human chromosome 21 is the only chromosome in human genome that exhibits oscillation of (G+C)-content of cycle length of hundreds kilobases (500 kb near the right telomere). We aim at establishing the existence of similar periodicity in structure-related sequence features in order to relate this (G+C)% oscillation to o...
biology
5,053
Modeling gene's length distribution in genomes
q-bio.GN
We show, that the specific distribution of gene's length, which is observed in natural genomes, might be a result of a growth process, in which a single length scale $L(t)$ develops that grows with time as $t^{1/3}$. This length scale could be associated with the length of the longest gene in an evolving genome. The gr...
biology
5,054
Mathematic principles underlying genetic structures
q-bio.GN
Many people are familiar with the physico-chemical properties of gene sequences. In this paper I present a mathematical perspective: how do mathematical principles such as information theory, coding theory, and combinatorics influence the beginnings of life and the formation of the genetic codes we observe today? What ...
biology
5,055
Invertibility of the TKF model of sequence evolution
q-bio.GN
We consider character sequences evolving on a phylogenetic tree under the TKF91 model. We show that as the sequence lengths tend to infinity the the topology of the phylogenetic tree and the edge lengths are determined by any one of (a) the alignment of sequences (b) the collection of sequence lengths. We also show tha...
biology
5,056
Maximum-frequency gene tree: a simplified genome-scale approach to overcoming incongruence in molecular phylogenies
q-bio.GN
Genomes and genes diversify during evolution; however, it is unclear to what extent genes still retain the relationship among species. Model species for molecular phylogenetic studies include yeasts and viruses whose genomes were sequenced as well as plants that have the fossil-supported true phylogenetic trees availab...
biology
5,057
Genome-wide EST data mining approaches to resolving incongruence of molecular phylogenies
q-bio.GN
36 single genes of six plants inferred 18 unique trees using maximum parsimony. Such incongruence is an important issue and how to reconstruct the congruent tree still is one of the most challenges in molecular phylogenetics. For resolving this problem, a genome-wide EST data mining approach was systematically investig...
biology
5,058
Expression of MHC II genes
q-bio.GN
Innate and adaptive immunity are connected via antigen processing and presentation (APP), which results in the presentation of antigenic peptides to T cells in the complex with the major histocompatibility (MHC) determinants. MHC class II (MHC II) determinants present antigens to CD4+ T cells, which are the main regula...
biology
5,059
Reconsidering the significance of genomic word frequency
q-bio.GN
We propose that the distribution of DNA words in genomic sequences can be primarily characterized by a double Pareto-lognormal distribution, which explains lognormal and power-law features found across all known genomes. Such a distribution may be the result of completely random sequence evolution by duplication proces...
biology
5,060
Cell wall proteins: a new insight through proteomics
q-bio.GN
Cell wall proteins are essential constituents of plant cell walls; they are involved in modifications of cell wall components, wall structure, signaling and interactions with plasma membrane proteins at the cell surface. The application of proteomic approaches to the cell wall compartment raises important questions: ar...
biology
5,061
Evaluation of cell wall preparations for proteomics: a new procedure for purifying cell walls from Arabidopsis hypocotyls
q-bio.GN
The ultimate goal of proteomic analysis of a cell compartment should be the exhaustive identification of resident proteins; excluding proteins from other cell compartments. Plant cell walls possess specific difficulties. Several reported procedures to isolate cell walls for proteomic analyses led to the isolation of a ...
biology
5,062
The riddle of the plant vacuolar sorting receptors
q-bio.GN
Proteins synthesized on membrane-bound ribosomes are sorted at the Golgi apparatus level for delivery to various cellular destinations: the plasma membrane or the extracellular space, and the lytic vacuole or lysosome. Sorting involves the assembly of vesicles, which preferentially package soluble proteins with a commo...
biology
5,063
Correlated fragile site expression allows the identification of candidate fragile genes involved in immunity and associated with carcinogenesis
q-bio.GN
Common fragile sites (cfs) are specific regions in the human genome that are particularly prone to genomic instability under conditions of replicative stress. Several investigations support the view that common fragile sites play a role in carcinogenesis. We discuss a genome-wide approach based on graph theory and Gene...
biology
5,064
Proteomic nonlinear waves in networks of transcriptional regulators
q-bio.GN
A chain of connected genes with activation-repression links is analysed. It is shown that for various promoter activity functions (parametrised by Hill coefficient) the equations describing the concentrations of transcription factors, are differential-difference KdV-type with perturbations. In the case of large Hill co...
biology
5,065
Networks from gene expression time series: characterization of correlation patterns
q-bio.GN
This paper describes characteristic features of networks reconstructed from gene expression time series data. Several null models are considered in order to discriminate between informations embedded in the network that are related to real data, and features that are due to the method used for network reconstruction (t...
biology
5,066
How much non-coding DNA do eukaryotes require?
q-bio.GN
Despite tremendous advances in the field of genomics, the amount and function of the large non-coding part of the genome in higher organisms remains poorly understood. Here we report an observation, made for 37 fully sequenced eukaryotic genomes, which indicates that eukaryotes require a certain minimum amount of non-c...
biology
5,067
Di-nucleotide Entropy as a Measure of Genomic Sequence Functionality
q-bio.GN
Considering vast amounts of genomic sequences of mostly unknown functionality, in-silico prediction of functional regions is an important enterprise. Many genomic browsers employ GC content, which was observed to be elevated in gene-rich functional regions. This report shows that the entropy of di- and tri-nucleotides ...
biology
5,068
Genetic Variability of Splicing Sites
q-bio.GN
Splicing sites provide unique statistics in human genome due to their large number and reasonably complete annotation. Analyses of the cumulative SNPs distribution in splicing sites reveal a few interesting observations. While a degree of the nucleotide conservation reflects on the SNPs density monotonically, no detect...
biology
5,069
Progress in the definition of a reference human mitochondrial proteome
q-bio.GN
Owing to the complexity of higher eukaryotic cells, a complete proteome is likely to be very difficult to achieve. However, advantage can be taken of the cell compartmentalization to build organelle proteomes, which can moreover be viewed as specialized tools to study specifically the biology and "physiology" of the ta...
biology
5,070
Evaluation of nonionic and zwitterionic detergents as membrane protein solubilizers in two-dimensional electrophoresis
q-bio.GN
The solubilizing power of various nonionic and zwitterionic detergents as membrane protein solubilizers for two-dimensional electrophoresis was investigated. Human red blood cell ghosts and Arabidopsis thaliana leaf membrane proteins were used as model systems. Efficient detergents could be found in each class, i.e. wi...
biology
5,071
Detergents and Chaotropes for Protein Solubilization before Two-Dimensional Electrophoresis
q-bio.GN
Because of the outstanding separating capabilities of two-dimensional electrophoresis for complete proteins, it would be advantageous to be able to apply it to all types of proteins. Unfortunately, severe solubility problems hamper the analysis of many classes of proteins, but especially membrane proteins. These proble...
biology
5,072
About thiol derivatization and resolution of basic proteins in two-dimensional electrophoresis
q-bio.GN
The influence of thiol blocking on the resolution of basic proteins by two-dimensional electrophoresis was investigated. Cysteine blocking greatly increased resolution and decreased streaking, especially in the basic region of the gels. Two strategies for cysteine blocking were found to be efficient: classical alkylati...
biology
5,073
Alterations of the mitochondrial proteome caused by the absence of mitochondrial DNA: A proteomic view
q-bio.GN
The proper functioning of mitochondria requires that both the mitochondrial and the nuclear genome are functional. To investigate the importance of the mitochondrial genome, which encodes only 13 subunits of the respiratory complexes, the mitochondrial rRNAs and a few tRNAs, we performed a comparative study on the 143B...
biology
5,074
High expression of antioxidant proteins in dendritic cells: possible implications in atherosclerosis
q-bio.GN
Dendritic cells (DCs) display the unique ability to activate naive T cells and to initiate primary T cell responses revealed in DC-T cell alloreactions. DCs frequently operate under stress conditions. Oxidative stress enhances the production of inflammatory cytokines by DCs. We performed a proteomic analysis to see whi...
biology
5,075
Improved mass spectrometry compatibility is afforded by ammoniacal silver staining
q-bio.GN
Sequence coverage in MS analysis of protein digestion-derived peptides is a key issue for detailed characterization of proteins or identification at low quantities. In gel-based proteomics studies, the sequence coverage greatly depends on the protein detection method. It is shown here that ammoniacal silver detection m...
biology
5,076
A versatile electrophoresis system for the analysis of high- and low-molecular-weight proteins
q-bio.GN
A new, versatile, multiphasic buffer system for high-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins in the relative molecular weight range of 300 000-3000 Da is described. The system, based on the theory of multiphasic zone electrophoresis, allows complete stacking and destacking of pr...
biology
5,077
Improvement of the solubilization of proteins in two-dimensional electrophoresis with immobilized pH gradients
q-bio.GN
Membrane and nuclear proteins of poor solubility have been separated by high resolution two-dimensional (2-D) gel electrophoresis. Isoelectric focusing with immobilized pH gradients leads to severe quantitative losses of proteins in the resulting 2-D map, although the resolution is usually high. Protein solubility coul...
biology
5,078
Gene induction during differentiation of human monocytes into dendritic cells: an integrated study at the RNA and protein levels
q-bio.GN
Changes in gene expression occurring during differentiation of human monocytes into dendritic cells were studied at the RNA and protein levels. These studies showed the induction of several gene classes corresponding to various biological functions. These functions encompass antigen processing and presentation, cytoske...
biology
5,079
Linguistic mechanism of the evolution of amino acid frequencies and genomic GC content
q-bio.GN
Much information is stored in amino acid composition of protein and base composition of DNA. We simulated the evolution of amino acid frequencies and genomic GC content by a linguistic model. It is showed that the evolution of genetic code determines the evolution of amino acid frequencies and genomic GC content. We ex...
biology
5,080
Motif Discovery through Predictive Modeling of Gene Regulation
q-bio.GN
We present MEDUSA, an integrative method for learning motif models of transcription factor binding sites by incorporating promoter sequence and gene expression data. We use a modern large-margin machine learning approach, based on boosting, to enable feature selection from the high-dimensional search space of candidate...
biology
5,081
Marker enzyme phenotype ratios in agamospermous sugarbeet progenies as a demonstration of multidimensional encoding of inherited information in plants
q-bio.GN
It has been demonstrated that the observed ratio of phenotypes of marker enzymes in some sugarbeet plants produced by mitotic agamospermy can be explained by different degrees of endoreduplication of chromosomes carrying different alleles of the enzyme loci. In these plants, different patterns of variability of the enz...
biology
5,082
Finding Sequence Features in Tissue-specific Sequences
q-bio.GN
The discovery of motifs underlying gene expression is a challenging one. Some of these motifs are known transcription factors, but sequence inspection often provides valuable clues, even discovery of novel motifs with uncharacterized function in gene expression. Coupled with the complexity underlying tissue-specific ge...
biology
5,083
Bacteria are not Lamarckian
q-bio.GN
Instructive influence of environment on heredity has been a debated topic for centuries. Darwin's identification of natural selection coupled to chance variation as the driving force for evolution, against a formal interpretation proposed by Lamarck, convinced most scientists that environment does not specifically inst...
biology
5,084
Nucleotide Distribution Patterns in Insect Genomes
q-bio.GN
This work analyzed genome-wide nucleotide distribution patterns in ten insect genomes. Two internal measures were applied: (i) GC variation and (ii) third codon nucleotide preference. Although the genome size and overall GC level did not show any correlation with insect order, the internal measures usually displayed hi...
biology
5,085
Ultraconserved Sequences in the Honeybee Genome - Are GC-rich Regions Preferred?
q-bio.GN
Among all insect genomes, honeybee displays one of the most unusual patterns with interspersed long AT and GC-rich segments. Nearly 75% of the protein-coding genes are located in the AT-rich segments of the genome, but the biological significance of the GC-rich regions is not well understood. Based on an observation th...
biology
5,086
Toward a better analysis of secreted proteins: the example of the myeloid cells secretome
q-bio.GN
The analysis of secreted proteins represents a challenge for current proteomics techniques. Proteins are usually secreted at low concentrations in the culture media, which makes their recovery difficult. In addition, culture media are rich in salts and other compounds interfering with most proteomics techniques, which ...
biology
5,087
Noise-filtering features of transcription regulation in the yeast S. cerevisiae
q-bio.GN
Transcription regulation is largely governed by the profile and the dynamics of transcription factors' binding to DNA. Stochastic effects are intrinsic to this dynamics and the binding to functional sites must be controled with a certain specificity for living organisms to be able to elicit specific cellular responses....
biology
5,088
Mismatch Repair Error Implies Chargaff's Second Parity Rule
q-bio.GN
Chargaff's second parity rule holds empirically for most types of DNA that along single strands of DNA the base contents are equal for complimentary bases, A = T, G = C. A Markov chain model is constructed to track the evolution of any single base position along single strands of genomes whose organisms are equipped wi...
biology
5,089
Chromatin Folding in Relation to Human Genome Function
q-bio.GN
Three-dimensional (3D) chromatin structure is closely related to genome function, in particular transcription. However, the folding path of the chromatin fiber in the interphase nucleus is unknown. Here, we systematically measured the 3D physical distance between pairwise labeled genomic positions in gene-dense, highly...
biology
5,090
Reciprocal best hits are not a logically sufficient condition for orthology
q-bio.GN
It is common to use reciprocal best hits, also known as a boomerang criterion, for determining orthology between sequences. The best hits may be found by blast, or by other more recently developed algorithms. Previous work seems to have assumed that reciprocal best hits is a sufficient but not necessary condition for o...
biology
5,091
Codon Usage Bias Measured Through Entropy Approach
q-bio.GN
Codon usage bias measure is defined through the mutual entropy calculation of real codon frequency distribution against the quasi-equilibrium one. This latter is defined in three manners: (1) the frequency of synonymous codons is supposed to be equal (i.e., the arithmetic mean of their frequencies); (2) it coincides to...
biology
5,092
OrfMapper: A Web-Based Application for Visualizing Gene Clusters on Metabolic Pathway Maps
q-bio.GN
Computational analyses of, e.g., genomic, proteomic, or metabolomic data, commonly result in one or more sets of candidate genes, proteins, or enzymes. These sets are often the outcome of clustering algorithms. Subsequently, it has to be tested if, e.g., the candidate gene-products are members of known metabolic proces...
biology
5,093
Silver staining of proteins in polyacrylamide gels
q-bio.GN
Silver staining is used to detect proteins after electrophoretic separation on polyacrylamide gels. It combines excellent sensitivity (in the low nanogram range) with the use of very simple and cheap equipment and chemicals. It is compatible with downstream processing, such as mass spectrometry analysis after protein d...
biology
5,094
Identification of candidate regulatory sequences in mammalian 3' UTRs by statistical analysis of oligonucleotide distributions
q-bio.GN
3' untranslated regions (3' UTRs) contain binding sites for many regulatory elements, and in particular for microRNAs (miRNAs). The importance of miRNA-mediated post-transcriptional regulation has become increasingly clear in the last few years. We propose two complementary approaches to the statistical analysis of o...
biology
5,095
Global regulation of genome duplication in eukaryotes: an overview from the epifluorescence microscope
q-bio.GN
In eukaryotes, DNA replication is initiated along each chromosome at multiple sites called replication origins. Locally, each replication origin is "licensed", or specified, at the end of the M and the beginning of G1 phases of the cell cycle. During S phase when DNA synthesis takes place, origins are activated in stag...
biology
5,096
Genomes: at the edge of chaos with maximum information capacity
q-bio.GN
We propose an order index, phi, which quantifies the notion of ``life at the edge of chaos'' when applied to genome sequences. It maps genomes to a number from 0 (random and of infinite length) to 1 (fully ordered) and applies regardless of sequence length. The 786 complete genomic sequences in GenBank were found to ha...
biology
5,097
Genome landscapes and bacteriophage codon usage
q-bio.GN
Across all kingdoms of biological life, protein-coding genes exhibit unequal usage of synonmous codons. Although alternative theories abound, translational selection has been accepted as an important mechanism that shapes the patterns of codon usage in prokaryotes and simple eukaryotes. Here we analyze patterns of codo...
biology
5,098
CompostBin: A DNA composition-based algorithm for binning environmental shotgun reads
q-bio.GN
A major hindrance to studies of microbial diversity has been that the vast majority of microbes cannot be cultured in the laboratory and thus are not amenable to traditional methods of characterization. Environmental shotgun sequencing (ESS) overcomes this hurdle by sequencing the DNA from the organisms present in a mi...
biology
5,099
Ultrafast coelectrophoretic fluorescent staining of proteins with carbocyanines
q-bio.GN
Protein detection on SDS gels or on 2-D gels must combine several features, such as sensitivity, homogeneity from one protein to another, speed, low cost, and user-friendliness. For some applications, it is also interesting to have a nonfixing stain, so that proteins can be mobilized from the gel for further use (elect...
biology