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Gene noise

Qiuhong Xue, Caihong Li, Jia Chen, Hongmei Guo, Dongqing Li, Xianglei Wu
CONTEXT: The audiological features and cochlear morphology of individuals with noise-induced hearing loss (NIHL) are well characterized. However, the molecular processes in the cochlea are not well understood. AIMS: To explore the role of the endoplasmic reticulum stress (ERS) response in the guinea pig model of cochlear damage induced by exposure to intense noise. SETTINGS AND DESIGN: A pilot case-control study. SUBJECTS AND METHODS: Forty-eight guinea pigs were divided into four equal groups...
September 2016: Noise & Health
Jeffrey A Walker
BACKGROUND: Self-contained tests estimate and test the association between a phenotype and mean expression level in a gene set defined a priori. Many self-contained gene set analysis methods have been developed but the performance of these methods for phenotypes that are continuous rather than discrete and with multiple nuisance covariates has not been well studied. Here, I use Monte Carlo simulation to evaluate the performance of both novel and previously published (and readily available via R) methods for inferring effects of a continuous predictor on mean expression in the presence of nuisance covariates...
2016: PeerJ
Jakub Jędrak, Anna Ochab-Marcinek
We study a stochastic model of gene expression, in which protein production has a form of random bursts whose size distribution is arbitrary, whereas protein decay is a first-order reaction. We find exact analytical expressions for the time evolution of the cumulant-generating function for the most general case when both the burst size probability distribution and the model parameters depend on time in an arbitrary (e.g., oscillatory) manner, and for arbitrary initial conditions. We show that in the case of periodic external activation and constant protein degradation rate, the response of the gene is analogous to the resistor-capacitor low-pass filter, where slow oscillations of the external driving have a greater effect on gene expression than the fast ones...
September 2016: Physical Review. E
Anatoly Yambartsev, Michael A Perlin, Yevgeniy Kovchegov, Natalia Shulzhenko, Karina L Mine, Xiaoxi Dong, Andrey Morgun
BACKGROUND: Gene covariation networks are commonly used to study biological processes. The inference of gene covariation networks from observational data can be challenging, especially considering the large number of players involved and the small number of biological replicates available for analysis. RESULTS: We propose a new statistical method for estimating the number of erroneous edges in reconstructed networks that strongly enhances commonly used inference approaches...
October 13, 2016: Biology Direct
Ji-Yong An, Zhu-Hong You, Xing Chen, De-Shuang Huang, Zheng-Wei Li, Gang Liu, Yin Wang
Self-interacting Proteins (SIPs) play an essential role in a wide range of biological processes, such as gene expression regulation, signal transduction, enzyme activation and immune response. Because of the limitations for experimental self-interaction proteins identification, developing an effective computational method based on protein sequence to detect SIPs is much important. In the study, we proposed a novel computational approach called RVMBIGP that combines the Relevance Vector Machine (RVM) model and Bi-gram probability (BIGP) to predict SIPs based on protein sequence...
October 8, 2016: Oncotarget
Laurent Potvin-Trottier, Nathan D Lord, Glenn Vinnicombe, Johan Paulsson
Synthetically engineered genetic circuits can perform a wide variety of tasks but are generally less accurate than natural systems. Here we revisit the first synthetic genetic oscillator, the repressilator, and modify it using principles from stochastic chemistry in single cells. Specifically, we sought to reduce error propagation and information losses, not by adding control loops, but by simply removing existing features. We show that this modification created highly regular and robust oscillations. Furthermore, some streamlined circuits kept 14 generation periods over a range of growth conditions and kept phase for hundreds of generations in single cells, allowing cells in flasks and colonies to oscillate synchronously without any coupling between them...
October 12, 2016: Nature
Pablo Villegas, José Ruiz-Franco, Jorge Hidalgo, Miguel A Muñoz
Gene regulatory networks can be successfully modeled as Boolean networks. A much discussed hypothesis says that such model networks reproduce empirical findings the best if they are tuned to operate at criticality, i.e. at the borderline between their ordered and disordered phases. Critical networks have been argued to lead to a number of functional advantages such as maximal dynamical range, maximal sensitivity to environmental changes, as well as to an excellent tradeoff between stability and flexibility...
October 7, 2016: Scientific Reports
Rongfei Han, Guanqun Huang, Yejun Wang, Yafei Xu, Yueming Hu, Wenqi Jiang, Tianfu Wang, Tian Xiao, Duo Zheng
Gene expression in metazoans is delicately organized. As genetic information transmits from DNA to RNA and protein, expression noise is inevitably generated. Recent studies begin to unveil the mechanisms of gene expression noise control, but the changes of gene expression precision in pathologic conditions like cancers are unknown. Here we analyzed the transcriptomic data of human breast, liver, lung and colon cancers, and found that the expression noise of more than 74.9% genes was increased in cancer tissues as compared to adjacent normal tissues...
October 4, 2016: Oncotarget
L Sun, J-C Xu, W Wang, Y Yin
Cancer subtype recognition and feature selection are important problems in the diagnosis and treatment of tumors. Here, we propose a novel gene selection approach applied to gene expression data classification. First, two classical feature reduction methods including locally linear embedding (LLE) and rough set (RS) are summarized. The advantages and disadvantages of these algorithms were analyzed and an optimized model for tumor gene selection was developed based on LLE and neighborhood RS (NRS). Bhattacharyya distance was introduced to delete irrelevant genes, pair-wise redundant analysis was performed to remove strongly correlated genes, and the wavelet soft threshold was determined to eliminate noise in the gene datasets...
August 30, 2016: Genetics and Molecular Research: GMR
Weilin Peng, Ruijie Song, Murat Acar
Genetic noise together with genome duplication and volume changes during cell cycle are significant contributors to cell-to-cell heterogeneity. How can cells buffer the effects of these unavoidable epigenetic and genetic variations on phenotypes that are sensitive to such variations? Here we show that a simple network motif that is essential for network-dosage compensation can reduce the effects of extrinsic noise on the network output. Using natural and synthetic gene networks with and without the network motif, we measure gene network activity in single yeast cells and find that the activity of the compensated network is significantly lower in noise compared with the non-compensated network...
October 3, 2016: Nature Communications
Yanushi D Wijeyeratne, Elijah R Behr
Approximately 4% of sudden cardiac deaths are unexplained [the sudden arrhythmic death syndrome (SADS)], and up to 6-10% of survivors of cardiac arrest do not have an identifiable cardiac abnormality after comprehensive clinical evaluation [idiopathic ventricular fibrillation (IVF)]. Genetic testing may be able to play a role in diagnostics and can be targeted to an underlying phenotype present in family members following clinical evaluation. Alternatively, post-mortem genetic testing (the "molecular autopsy") may diagnose the underlying cause if a clearly pathogenic rare variant is found...
August 31, 2016: Trends in Cardiovascular Medicine
Xu Tang, Yin-Yin Xia, Jing-Yuan Tang, Hua Dai, Xing-Can Liu, Shu-Qun Cheng, Pan Meng, Rui-Yuan Zhang
OBJECTIVE: To explore the effect of exposure to vehicle exhaust in pregnant mice on the reproductive function and DNA methylation in male offspring mice. METHODS: Twenty pregnant mice were randomized into control group and vehicle exhaust exposure group (n=10) and exposed to routine laboratory condition and to vehicle exhaust for 10 consecutive days (8 h per day) in a tunnel with a heavy traffic, where the concentrations of TSP, PM10, PM2.5, SO2 and NOX and the decibel of noise were measured...
August 20, 2016: Nan Fang Yi Ke da Xue Xue Bao, Journal of Southern Medical University
Patrick Hillenbrand, Ulrich Gerland, Gašper Tkačik
A crucial step in the early development of multicellular organisms involves the establishment of spatial patterns of gene expression which later direct proliferating cells to take on different cell fates. These patterns enable the cells to infer their global position within a tissue or an organism by reading out local gene expression levels. The patterning system is thus said to encode positional information, a concept that was formalized recently in the framework of information theory. Here we introduce a toy model of patterning in one spatial dimension, which can be seen as an extension of Wolpert's paradigmatic "French Flag" model, to patterning by several interacting, spatially coupled genes subject to intrinsic and extrinsic noise...
2016: PloS One
Chang Lu, Jun Wang, Zili Zhang, Pengyi Yang, Guoxian Yu
Gene Ontology (GO) provides GO annotations (GOA) that associate gene products with GO terms that summarize their cellular, molecular and functional aspects in the context of biological pathways. GO Consortium (GOC) resorts to various quality assurances to ensure the correctness of annotations. Due to resources limitations, only a small portion of annotations are manually added/checked by GO curators, and a large portion of available annotations are computationally inferred. While computationally inferred annotations provide greater coverage of known genes, they may also introduce annotation errors (noise) that could mislead the interpretation of the gene functions and their roles in cellular and biological processes...
September 13, 2016: Computational Biology and Chemistry
Pavol Bokes, Abhyudai Singh
Inside individual cells, expression of genes is stochastic across organisms ranging from bacterial to human cells. A ubiquitous feature of stochastic expression is burst-like synthesis of gene products, which drives considerable intercellular variability in protein levels across an isogenic cell population. One common mechanism by which cells control such stochasticity is negative feedback regulation, where a protein inhibits its own synthesis. For a single gene that is expressed in bursts, negative feedback can affect the burst frequency or the burst size...
September 24, 2016: Journal of Mathematical Biology
Chunxuan Shao, Thomas Höfer
MOTIVATION: Single-cell transcriptome data provide unprecedented resolution to study heterogeneity in cell populations and present a challenge for unsupervised classification. Popular methods, like principal component analysis (PCA), often suffer from the high level of noise in the data. RESULTS: Here we adapt Nonnegative Matrix Factorization (NMF) to study the problem of identifying subpopulations in single-cell transcriptome data. In contrast to the conventional gene-centered view of NMF, identifying metagenes, we used NMF in a cell-centered direction, identifying cell subtypes ('metacells')...
September 23, 2016: Bioinformatics
Patrick Conlon, Rita Gelin-Licht, Ambhighainath Ganesan, Jin Zhang, Andre Levchenko
In response to pheromones, yeast cells activate a MAPK pathway to direct processes important for mating, including gene induction, cell-cycle arrest, and polarized cell growth. Although a variety of assays have been able to elucidate signaling activities at multiple steps in the pathway, measurements of MAPK activity during the pheromone response have remained elusive, and our understanding of single-cell signaling behavior is incomplete. Using a yeast-optimized FRET-based mammalian Erk-activity reporter to monitor Fus3 and Kss1 activity in live yeast cells, we demonstrate that overall mating MAPK activity exhibits distinct temporal dynamics, rapid reversibility, and a graded dose dependence around the KD of the receptor, where phenotypic transitions occur...
October 4, 2016: Proceedings of the National Academy of Sciences of the United States of America
Nicolas Perrin
Sex-determining factors are usually assumed to be either genetic or environmental. The present paper aims at drawing attention to the potential contribution of developmental noise, an important but often-neglected component of phenotypic variance. Mutual inhibitions between male and female pathways make sex a bistable equilibrium, such that random fluctuations in the expression of genes at the top of the cascade are sufficient to drive individual development toward one or the other stable state. Evolutionary modeling shows that stochastic sex determinants should resist elimination by genetic or environmental sex determinants under ecologically meaningful settings...
September 19, 2016: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
Sayuri K Hahl, Andreas Kremling
In the mathematical modeling of biochemical reactions, a convenient standard approach is to use ordinary differential equations (ODEs) that follow the law of mass action. However, this deterministic ansatz is based on simplifications; in particular, it neglects noise, which is inherent to biological processes. In contrast, the stochasticity of reactions is captured in detail by the discrete chemical master equation (CME). Therefore, the CME is frequently applied to mesoscopic systems, where copy numbers of involved components are small and random fluctuations are thus significant...
2016: Frontiers in Genetics
J Chris Pires, Gavin C Conant
The complex manner in which organisms respond to changes in their gene dosage has long fascinated geneticists. Oddly, although the existence of dominance implies that dosage reductions often have mild phenotypes, extra copies of whole chromosomes (aneuploidy) are generally strongly deleterious. Even more paradoxically, an extra copy of the genome is better tolerated than is aneuploidy. We review the resolution of this paradox, highlighting the roles of biochemistry, protein aggregation, and disruption of cellular microstructure in that explanation...
September 12, 2016: Annual Review of Genetics
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