scholarly journals Acute condensin depletion causes genome decompaction without altering the level of global gene expression in Saccharomyces cerevisiae

2017 ◽  
Author(s):  
Matthew Robert Paul ◽  
Tovah Elise Markowitz ◽  
Andreas Hochwagen ◽  
Sevinç Ercan

AbstractCondensins are broadly conserved chromosome organizers that function in chromatin compaction and transcriptional regulation, but to what extent these two functions are linked has remained unclear. Here, we analyzed the effect of condensin inactivation on genome compaction and global gene expression in the yeast Saccharomyces cerevisiae. Spike-in-controlled 3C-seq analysis revealed that acute condensin inactivation leads to a global decrease in close-range chromosomal interactions as well as more specific losses of homotypic tRNA gene clustering. In addition, a condensin-rich topologically associated domain between the ribosomal DNA and the centromere on chromosome XII is lost upon condensin inactivation. Unexpectedly, these large-scale changes in chromosome architecture are not associated with global changes in transcript levels as determined by spike-in-controlled mRNA-seq analysis. Our data suggest that the global transcriptional program of S. cerevisiae is resistant to condensin inactivation and the associated profound changes in genome organization.Significance StatementGene expression occurs in the context of higher-order chromatin organization, which helps compact the genome within the spatial constraints of the nucleus. To what extent higher-order chromatin compaction affects gene expression remains unknown. Here, we show that gene expression and genome compaction can be uncoupled in the single-celled model eukaryote Saccharomyces cerevisiae. Inactivation of the conserved condensin complex, which also organizes the human genome, leads to broad genome decompaction in this organism. Unexpectedly, this reorganization has no immediate effect on the transcriptome. These findings indicate that the global gene expression program is robust to large-scale changes in genome architecture in yeast, shedding important new light on the evolution and function of genome organization in gene regulation.

2019 ◽  
Author(s):  
Muhammad Shuaib ◽  
Krishna Mohan Parsi ◽  
Hideya Kawaji ◽  
Manjula Thimma ◽  
Sabir Abdu Adroub ◽  
...  

AbstractAside from their roles in the cytoplasm, RNA-interference components have been reported to localize also in the nucleus of human cells. In particular, AGO1 associates with active chromatin and appears to influence global gene expression. However, the mechanistic aspects remain elusive. Here, we identify AGO1 as a paraspeckle component that in combination with the NEAT1 lncRNA maintains 3D genome architecture. We demonstrate that AGO1 interacts with NEAT1 lncRNA and its depletion affects NEAT1 expression and the formation of paraspeckles. By Hi-C analysis in AGO1 knockdown cells, we observed global changes in chromatin organization, including TADs configuration, and A/B compartment mixing. Consistently, distinct groups of genes located within the differential interacting loci showed altered expression upon AGO1 depletion. NEAT1 knockout cells displayed similar changes in TADs and higher-order A/B compartmentalization. We propose that AGO1 in association with NEAT1 lncRNA can act as a scaffold that bridges chromatin and nuclear bodies to regulate genome organization and gene expression in human cells.


2002 ◽  
Vol 9 (3) ◽  
pp. 145-155 ◽  
Author(s):  
Chang-Fu Peng ◽  
Yi Wei ◽  
Jeffrey M. Levsky ◽  
Thomas V. McDonald ◽  
Geoffrey Childs ◽  
...  

Significant progress has been made in defining pathways that mediate the formation of the mammalian heart. Little is known, however, about the genetic program that directs the differentiation of cardiac myocytes from their precursor cells. A major hindrance to this kind of investigation has been the absence of an appropriate cell culture model of cardiac myocyte differentiation. Recently, a subline of P19 cells (P19CL6) was derived that, following dimethyl sulfoxide (DMSO) treatment, differentiate efficiently over 10 days into spontaneously beating cardiac myocytes. We demonstrate that these cells are indeed cardiac myocytes as they express cell type-specific markers and exhibit electrophysiological properties indicative of cardiac myocytes. The requirement for DMSO stimulation in this paradigm was shown to be limited to the first 4 days, suggesting that critical events in the differentiation process occur over this interval. To uncover relationships among known genes and identify novel genes that mediate cardiac myocyte differentiation, a detailed time course of changes in global gene expression was carried out using cDNA microarrays. In addition to the activation of genes encoding cardiac transcription factors and structural proteins, increases were noted in the expression of multiple known genes and expressed sequence tags (ESTs). Analysis of the former suggested the involvement of a variety of signaling pathways in cardiac myocyte differentiation. The 16 ESTs whose expression was increased during the early, stimulus-dependent phase of cardiac myocyte differentiation may be novel regulators of this process. Thus this first report of large-scale changes in gene expression during cardiac myocyte differentiation has delineated relationships among the expression patterns of known genes and identified a number of novel genes that merit further study.


2004 ◽  
Vol 18 (2) ◽  
pp. 167-183 ◽  
Author(s):  
Jianhua Zhang ◽  
Amy Moseley ◽  
Anil G. Jegga ◽  
Ashima Gupta ◽  
David P. Witte ◽  
...  

To understand the commitment of the genome to nervous system differentiation and function, we sought to compare nervous system gene expression to that of a wide variety of other tissues by gene expression database construction and mining. Gene expression profiles of 10 different adult nervous tissues were compared with that of 72 other tissues. Using ANOVA, we identified 1,361 genes whose expression was higher in the nervous system than other organs and, separately, 600 genes whose expression was at least threefold higher in one or more regions of the nervous system compared with their median expression across all organs. Of the 600 genes, 381 overlapped with the 1,361-gene list. Limited in situ gene expression analysis confirmed that identified genes did represent nervous system-enriched gene expression, and we therefore sought to evaluate the validity and significance of these top-ranked nervous system genes using known gene literature and gene ontology categorization criteria. Diverse functional categories were present in the 381 genes, including genes involved in intracellular signaling, cytoskeleton structure and function, enzymes, RNA metabolism and transcription, membrane proteins, as well as cell differentiation, death, proliferation, and division. We searched existing public sites and identified 110 known genes related to mental retardation, neurological disease, and neurodegeneration. Twenty-one of the 381 genes were within the 110-gene list, compared with a random expectation of 5. This suggests that the 381 genes provide a candidate set for further analyses in neurological and psychiatric disease studies and that as a field, we are as yet, far from a large-scale understanding of the genes that are critical for nervous system structure and function. Together, our data indicate the power of profiling an individual biologic system in a multisystem context to gain insight into the genomic basis of its structure and function.


Author(s):  
Gustavo Deco ◽  
Kevin Aquino ◽  
Aurina Arnatkevičiūtė ◽  
Stuart Oldham ◽  
Kristina Sabaroedin ◽  
...  

AbstractBrain regions vary in their molecular and cellular composition, but how this heterogeneity shapes neuronal dynamics is unclear. Here, we investigate the dynamical consequences of regional heterogeneity using a biophysical model of whole-brain functional magnetic resonance imaging (MRI) dynamics in humans. We show that models in which transcriptional variations in excitatory and inhibitory receptor (E:I) gene expression constrain regional heterogeneity more accurately reproduce the spatiotemporal structure of empirical functional connectivity estimates than do models constrained by global gene expression profiles and MRI-derived estimates of myeloarchitecture. We further show that regional heterogeneity is essential for yielding both ignition-like dynamics, which are thought to support conscious processing, and a wide variance of regional activity timescales, which supports a broad dynamical range. We thus identify a key role for E:I heterogeneity in generating complex neuronal dynamics and demonstrate the viability of using transcriptional data to constrain models of large-scale brain function.


2004 ◽  
Vol 70 (4) ◽  
pp. 2307-2317 ◽  
Author(s):  
Marco Sonderegger ◽  
Marie Jeppsson ◽  
Bärbel Hahn-Hägerdal ◽  
Uwe Sauer

ABSTRACT Yeast xylose metabolism is generally considered to be restricted to respirative conditions because the two-step oxidoreductase reactions from xylose to xylulose impose an anaerobic redox imbalance. We have recently developed, however, a Saccharomyces cerevisiae strain that is at present the only known yeast capable of anaerobic growth on xylose alone. Using transcriptome analysis of aerobic chemostat cultures grown on xylose-glucose mixtures and xylose alone, as well as a combination of global gene expression and metabolic flux analysis of anaerobic chemostat cultures grown on xylose-glucose mixtures, we identified the distinguishing characteristics of this unique phenotype. First, the transcript levels and metabolic fluxes throughout central carbon metabolism were significantly higher than those in the parent strain, and they were most pronounced in the xylose-specific, pentose phosphate, and glycerol pathways. Second, differential expression of many genes involved in redox metabolism indicates that increased cytosolic NADPH formation and NADH consumption enable a higher flux through the two-step oxidoreductase reaction of xylose to xylulose in the mutant. Redox balancing is apparently still a problem in this strain, since anaerobic growth on xylose could be improved further by providing acetoin as an external NADH sink. This improved growth was accompanied by an increased ATP production rate and was not accompanied by higher rates of xylose uptake or cytosolic NADPH production. We concluded that anaerobic growth of the yeast on xylose is ultimately limited by the rate of ATP production and not by the redox balance per se, although the redox imbalance, in turn, limits ATP production.


2008 ◽  
Vol 68 (2) ◽  
pp. 447-452 ◽  
Author(s):  
CA. Sommer ◽  
F. Henrique-Silva

Even though the molecular mechanisms underlying the Down syndrome (DS) phenotypes remain obscure, the characterization of the genes and conserved non-genic sequences of HSA21 together with large-scale gene expression studies in DS tissues are enhancing our understanding of this complex disorder. Also, mouse models of DS provide invaluable tools to correlate genes or chromosome segments to specific phenotypes. Here we discuss the possible contribution of HSA21 genes to DS and data from global gene expression studies of trisomic samples.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Chengcheng Wang ◽  
Zhouyan Guo ◽  
Xiechao Zhan ◽  
Fenghua Yang ◽  
Mingxuan Wu ◽  
...  

Abstract SWI/SNF remodelers play a key role in regulating chromatin architecture and gene expression. Here, we report the cryo-EM structure of the Saccharomyces cerevisiae Swi/Snf complex in a nucleosome-free state. The structure consists of a stable triangular base module and a flexible Arp module. The conserved subunits Swi1 and Swi3 form the backbone of the complex and closely interact with other components. Snf6, which is specific for yeast Swi/Snf complex, stabilizes the binding of the ATPase-containing subunit Snf2 to the base module. Comparison of the yeast Swi/Snf and RSC complexes reveals conserved structural features that govern the assembly and function of these two subfamilies of chromatin remodelers. Our findings complement those from recent structures of the yeast and human chromatin remodelers and provide further insights into the assembly and function of the SWI/SNF remodelers.


2012 ◽  
Vol 33 (7) ◽  
pp. 550-560 ◽  
Author(s):  
Guangdi Chen ◽  
Deqiang Lu ◽  
Huai Chiang ◽  
Dariusz Leszczynski ◽  
Zhengping Xu

1999 ◽  
Vol 19 (10) ◽  
pp. 6710-6719 ◽  
Author(s):  
Michael J. Lelivelt ◽  
Michael R. Culbertson

ABSTRACT mRNAs are monitored for errors in gene expression by RNA surveillance, in which mRNAs that cannot be fully translated are degraded by the nonsense-mediated mRNA decay pathway (NMD). RNA surveillance ensures that potentially deleterious truncated proteins are seldom made. NMD pathways that promote surveillance have been found in a wide range of eukaryotes. In Saccharomyces cerevisiae, the proteins encoded by the UPF1, UPF2, andUPF3 genes catalyze steps in NMD and are required for RNA surveillance. In this report, we show that the Upf proteins are also required to control the total accumulation of a large number of mRNAs in addition to their role in RNA surveillance. High-density oligonucleotide arrays were used to monitor global changes in the yeast transcriptome caused by loss of UPF gene function. Null mutations in the UPF genes caused altered accumulation of hundreds of mRNAs. The majority were increased in abundance, but some were decreased. The same mRNAs were affected regardless of which of the three UPF gene was inactivated. The proteins encoded byUPF-dependent mRNAs were broadly distributed by function but were underrepresented in two MIPS (Munich Information Center for Protein Sequences) categories: protein synthesis and protein destination. In a UPF + strain, the average level of expression of UPF-dependent mRNAs was threefold lower than the average level of expression of all mRNAs in the transcriptome, suggesting that highly abundant mRNAs were underrepresented. We suggest a model for how the abundance of hundreds of mRNAs might be controlled by the Upf proteins.


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