scholarly journals Mammalian gene expression variability is explained by underlying cell state

2019 ◽  
Author(s):  
Robert Foreman ◽  
Roy Wollman
Keyword(s):  
Gene Expression ◽  
Mammalian Cells ◽  
Qualitative Difference ◽  
Live Cells ◽  
Expression Variability ◽  
Cell State ◽  
Relative Contribution ◽  
Allele Specific ◽  
Poisson Limit ◽  
Transcriptional Bursting

AbstractGene expression variability in mammalian systems plays an important role in physiological and pathophysiological conditions. This variability can come from differential regulation related to cell state (extrinsic) and allele-specific transcriptional bursting (intrinsic). Yet, the relative contribution of these two distinct sources is unknown. Here we exploit the qualitative difference in the patterns of covariance between these two sources to quantify their relative contributions to expression variance in mammalian cells. Using multiplexed error robust RNA fluorescent in situ hybridization (MERFISH) we measured the multivariate gene expression distribution of 150 genes related to Ca2+ signaling coupled with the dynamic Ca2+ response of live cells to ATP. We show that after controlling for cellular phenotypic states such as size, cell cycle stage, and Ca2+ response to ATP, the remaining variability is effectively at the Poisson limit for most genes. These findings demonstrate that the majority of expression variability results from cell state differences and that the contribution of transcriptional bursting is relatively minimal.

scholarly journals On-microscope staging of live cells reveals changes in the dynamics of transcriptional bursting during differentiation

2021 ◽  
Author(s):  
Danuta M Jeziorska ◽  
Edward A J Tunnacliffe ◽  
Jill M Brown ◽  
Helena Ayyub ◽  
Jacqueline A Sloane-Stanley ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mammalian Cells ◽  
Transcriptional Activity ◽  
Dynamic Behaviour ◽  
Live Cells ◽  
Development And Differentiation ◽  
The Stability ◽  
Transcriptional Bursting ◽  
Behaviour Changes ◽  
Transcriptional State

Determining the mechanisms by which genes are switched on and off during development and differentiation is a key aim of current biomedical research. Gene transcription has been widely observed to occur in a discontinuous fashion, with short bursts of activity interspersed with longer periods of inactivity. It is currently not known if or how this dynamic behaviour changes as mammalian cells differentiate. To investigate this, using a newly developed on-microscope analysis, we monitored mouse α-globin transcription in live cells throughout sequential stages of erythropoiesis. We find that changes in the overall levels of α-globin transcription are most closely associated with changes in the fraction of time a gene spends in the active transcriptional state. We identify differences in the patterns of transcriptional bursting throughout differentiation, with maximal transcriptional activity occurring in the mid-phase of differentiation. Early in differentiation, we observe increased fluctuation in the patterns of transcriptional activity whereas at the peak of gene expression, in early and intermediate erythroblasts, transcription appears to be relatively stable and efficient. Later during differentiation as α-globin expression declines, we again observed more variability in transcription within individual cells. We propose that the observed changes in transcriptional behaviour may reflect changes in the stability of enhancer-promoter interactions and the formation of active transcriptional compartments as gene expression is turned on and subsequently declines at sequential stages of differentiation.

scholarly journals Chromosome-wide co-fluctuation of stochastic gene expression in mammalian cells

2019 ◽  
Author(s):  
Mengyi Sun ◽  
Jianzhi Zhang
Keyword(s):  
Gene Expression ◽  
Mammalian Cells ◽  
Three Dimensional ◽  
Sequencing Data ◽  
Chromatin Dynamics ◽  
Gene Expression Noise ◽  
Genes Encoding ◽  
The Face ◽  
Allele Specific ◽  
Genomic Scale

ABSTRACTGene expression is subject to stochastic noise, but to what extent and by which means such stochastic variations are coordinated among different genes are unclear. We hypothesize that neighboring genes on the same chromosome co-fluctuate in expression because of their common chromatin dynamics, and verify it at the genomic scale using allele-specific single-cell RNA-sequencing data of mouse cells. Unexpectedly, the co-fluctuation extends to genes that are over 60 million bases apart. We provide evidence that this long-range effect arises in part from chromatin co-accessibilities of linked loci attributable to three-dimensional proximity, which is much closer intra-chromosomally than inter-chromosomally. We further show that genes encoding components of the same protein complex tend to be chromosomally linked, likely resulting from natural selection for intracellular among-component dosage balance. These findings have implications for both the evolution of genome organization and optimal design of synthetic genomes in the face of gene expression noise.

scholarly journals Optoribogenetic control of regulatory RNA molecules

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Sebastian Pilsl ◽  
Charles Morgan ◽  
Moujab Choukeife ◽  
Andreas Möglich ◽  
Günter Mayer
Keyword(s):  
Gene Expression ◽  
Protein Function ◽  
Mammalian Cells ◽  
Regulatory Rna ◽  
Rna Molecules ◽  
Cell State ◽  
Non Invasive ◽  
Micro Rnas ◽  
Short Hairpin ◽  
Regulatory Rnas

Abstract Short regulatory RNA molecules underpin gene expression and govern cellular state and physiology. To establish an alternative layer of control over these processes, we generated chimeric regulatory RNAs that interact reversibly and light-dependently with the light-oxygen-voltage photoreceptor PAL. By harnessing this interaction, the function of micro RNAs (miRs) and short hairpin (sh) RNAs in mammalian cells can be regulated in a spatiotemporally precise manner. The underlying strategy is generic and can be adapted to near-arbitrary target sequences. Owing to full genetic encodability, it establishes optoribogenetic control of cell state and physiology. The method stands to facilitate the non-invasive, reversible and spatiotemporally resolved study of regulatory RNAs and protein function in cellular and organismal environments.

scholarly journals Allele-specific single-cell RNA sequencing reveals different architectures of intrinsic and extrinsic gene expression noises

2019 ◽  
Author(s):  
Mengyi Sun ◽  
Jianzhi Zhang
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Rna Sequencing ◽  
Intrinsic Noise ◽  
Mouse Fibroblast ◽  
Extrinsic Noise ◽  
Gene Expression Noise ◽  
Cell State ◽  
Single Cell Rna Sequencing ◽  
Allele Specific

ABSTRACTGene expression noise refers to the variation of the expression level of a gene among isogenic cells in the same environment, and has two sources: extrinsic noise arising from the disparity of the cell state and intrinsic noise arising from the stochastic process of gene expression in the same cell state. Due to the low throughput of the existing method for measuring the two noise components, the architectures of intrinsic and extrinsic expression noises remain elusive. Using allele-specific single-cell RNA sequencing, we here estimate the two noise components of 3975 genes in mouse fibroblast cells. Our analyses verify predicted influences of several factors such as the TATA-box and microRNA targeting on intrinsic and extrinsic noises and reveal gene function-associated noise trends implicating the action of natural selection. These findings unravel differential regulations, optimizations, and biological consequences of intrinsic and extrinsic noises and can aid the construction of desired synthetic circuits.

scholarly journals Simultaneous quantification of protein-DNA contacts and transcriptomes in single cells

2019 ◽  
Author(s):  
Koos Rooijers ◽  
Corina M. Markodimitraki ◽  
Franka J. Rang ◽  
Sandra S. de Vries ◽  
Alex Chialastri ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mammalian Cells ◽  
Single Cells ◽  
Critical Role ◽  
Nuclear Lamina ◽  
Cell Types ◽  
Chromatin Accessibility ◽  
Expression Variability ◽  
The Impact

AbstractThe epigenome plays a critical role in regulating gene expression in mammalian cells. However, understanding how cell-to-cell heterogeneity in the epigenome influences gene expression variability remains a major challenge. Here we report a novel method for simultaneous single-cell quantification of protein-DNA contacts with DamID and transcriptomics (scDamID&T). This method enables quantifying the impact of protein-DNA contacts on gene expression from the same cell. By profiling lamina-associated domains (LADs) in human cells, we reveal different dependencies between genome-nuclear lamina (NL) association and gene expression in single cells. In addition, we introduce the E. coli methyltransferase, Dam, as an in vivo marker of chromatin accessibility in single cells and show that scDamID&T can be utilized as a general technology to identify cell types in silico while simultaneously determining the underlying gene-regulatory landscape. With this strategy the effect of chromatin states, transcription factor binding, and genome organization on the acquisition of cell-type specific transcriptional programs can be quantified.

scholarly journals Genome-wide kinetic properties of transcriptional bursting in mouse embryonic stem cells

2020 ◽  
Vol 6 (25) ◽  
pp. eaaz6699 ◽  
Author(s):  
Hiroshi Ochiai ◽  
Tetsutaro Hayashi ◽  
Mana Umeda ◽  
Mika Yoshimura ◽  
Akihito Harada ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Mammalian Cells ◽  
Transcription Elongation ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cells ◽  
Kinetic Properties ◽  
Mrna Levels ◽  
Transcriptional Bursting

Transcriptional bursting is the stochastic activation and inactivation of promoters, contributing to cell-to-cell heterogeneity in gene expression. However, the mechanism underlying the regulation of transcriptional bursting kinetics (burst size and frequency) in mammalian cells remains elusive. In this study, we performed single-cell RNA sequencing to analyze the intrinsic noise and mRNA levels for elucidating the transcriptional bursting kinetics in mouse embryonic stem cells. Informatics analyses and functional assays revealed that transcriptional bursting kinetics was regulated by a combination of promoter- and gene body–binding proteins, including the polycomb repressive complex 2 and transcription elongation factors. Furthermore, large-scale CRISPR-Cas9–based screening identified that the Akt/MAPK signaling pathway regulated bursting kinetics by modulating transcription elongation efficiency. These results uncovered the key molecular mechanisms underlying transcriptional bursting and cell-to-cell gene expression noise in mammalian cells.

scholarly journals Genome-wide analysis of transcriptional bursting-induced noise in mammalian cells

2019 ◽  
Author(s):  
Hiroshi Ochiai ◽  
Tetsutaro Hayashi ◽  
Mana Umeda ◽  
Mika Yoshimura ◽  
Akihito Harada ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Transcription Elongation ◽  
Mapk Signaling ◽  
Kinetic Properties ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
A Genome ◽  
Transcriptional Bursting

AbstractTranscriptional bursting is stochastic activation and inactivation of promoters, leading to discontinuous production of mRNA, and is considered to be a contributing factor to cell-to-cell heterogeneity in gene expression. However, it remains elusive how the kinetic properties of transcriptional bursting (e.g., burst size, burst frequency, and noise induced by transcriptional bursting) are regulated in mammalian cells. In this study, we performed a genome-wide analysis of transcriptional bursting in mouse embryonic stem cells (mESCs) using single-cell RNA-sequencing. We found that the kinetics of transcriptional bursting was determined by a combination of promoter and gene body binding proteins, including polycomb repressive complex 2 and transcription elongation-related factors. Furthermore, large-scale CRISPR-Cas9-based screening and functional analysis revealed that the Akt/MAPK signaling pathway regulated bursting kinetics by modulating transcription elongation efficiency. These results uncover key molecular mechanisms underlying transcriptional bursting and cell-to-cell gene expression noise in mammalian cells.

scholarly journals Allelic correlation is a marker of tradeoffs between barriers to transmission of expression variability and signal responsiveness in genetic networks

2021 ◽  
Author(s):  
Ryan H Boe ◽  
Vinay Ayyappan ◽  
Lea Schuh ◽  
Arjun Raj
Keyword(s):  
Response Time ◽  
Mammalian Cells ◽  
Genetic Networks ◽  
Model Parameters ◽  
Mathematical Framework ◽  
Odds Ratios ◽  
Trade Off ◽  
Expression Variability ◽  
Noise Transmission ◽  
Allele Specific

Accurately functioning genetic networks should be responsive to signals but prevent transmission of stochastic bursts of expression. Existing data in mammalian cells suggests that such transcriptional "noise" is transmitted by some genes and not others, suggesting that noise transmission is tunable, perhaps at the expense of other signal processing capabilities. However, systematic claims about noise transmission in genetic networks have been limited by the inability to directly measure noise transmission. Here we build a mathematical framework capable of modeling allelic correlation and noise transmission. We find that allelic correlation and noise transmission correspond across a broad range of model parameters and network architectures. We further find that limiting noise transmission comes with the trade-off of being unresponsive to signals, and that within the parameter regimes that are responsive to signals, there is a further trade-off between response time and basal noise transmission. Using a published allele specific single cell RNA-sequencing dataset, we found that genes with high allelic odds ratios are enriched for cell-type specific functions, and that within multiple signaling pathways, factors which are upstream in the pathway have higher allelic odds ratios than downstream factors. Overall, our findings suggest that some degree of noise transmission is required to be responsive to signals, but that minimization of noise transmission can be accomplished by trading-off for a slower response time.

scholarly journals Allele-specific single-cell RNA sequencing reveals different architectures of intrinsic and extrinsic gene expression noises

2019 ◽  
Vol 48 (2) ◽  
pp. 533-547 ◽  
Author(s):  
Mengyi Sun ◽  
Jianzhi Zhang
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Rna Sequencing ◽  
Intrinsic Noise ◽  
Mouse Fibroblast ◽  
Extrinsic Noise ◽  
Gene Expression Noise ◽  
Cell State ◽  
Single Cell Rna Sequencing ◽  
Allele Specific

Abstract Gene expression noise refers to the variation of the expression level of a gene among isogenic cells in the same environment, and has two sources: extrinsic noise arising from the disparity of the cell state and intrinsic noise arising from the stochastic process of gene expression in the same cell state. Due to the low throughput of the existing method for measuring the two noise components, the architectures of intrinsic and extrinsic expression noises remain elusive. Using allele-specific single-cell RNA sequencing, we here estimate the two noise components of 3975 genes in mouse fibroblast cells. Our analyses verify predicted influences of several factors such as the TATA-box and microRNA targeting on intrinsic or extrinsic noises and reveal gene function-associated noise trends implicating the action of natural selection. These findings unravel differential regulations, optimizations, and biological consequences of intrinsic and extrinsic noises and can aid the construction of desired synthetic circuits.

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