Abstract 319: Structural Reorganization of Cardiac Transcription Factories Mediates Transcriptional Changes in Response to Stress

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Elaheh Karbassi ◽  
Manuel Rosa Garrido ◽  
Douglas J Chapski ◽  
Yong Wu ◽  
Emma Monte ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Three Dimensional ◽  
Pressure Overload ◽  
Structural Features ◽  
Cardiac Cells ◽  
Structural Reorganization ◽  
Transcription Factories ◽  
Response To Stress

The heart’s response to stress entails precise gene expression changes to affect the metabolic and structural features of the cardiomyocyte. The changes in gene expression are mediated by structural alterations in the packaging of the genome. However, the manner in which the three-dimensional architecture of the genome is established is unknown. In non-cardiac cells, genes that are actively transcribed are thought to reside in transcriptionally permissive compartments called transcription factories. The structural principles for achieving cardiac-specific transcription are not understood. We sought to understand the functional nature of cardiac transcription factories: whether they are stable structures (to which genes move in and out of) or are transiently formed around genes in response to cardiac stimuli. Using 5-fluorouridine incorporation into nascent RNA, we quantified changes in RNA polymerase II-mediated transcription in cardiomyocytes upon hypertrophic stress. Furthermore, we characterized the spatial distribution of transcription factories, marked by RNA polymerase II, from adult mice subjected to pressure overload. Using super-resolution microscopy, our analyses revealed reorganization of RNA polymerase II, evidenced by a significant increase in the distance between clusters (130nm in sham to 132.5nm in failing hearts, p=0.02) and a 38% increase in cluster intensity in failing hearts. To understand regulation of cardiac gene expression, we used DNA fluorescence in situ hybridization to map the nuclear position of the gene for SERCA2a (atp2a2), which is down regulated in disease. In failing hearts, we measured increased association of atp2a2 with the nuclear envelope (0/159 loci in sham to 11/278 loci in failure) and increased colocalization with heterochromatin (53/160 loci in sham versus 139/290 loci in failure), providing a structural mechanism for the decrease in SERCA2a expression. In contrast, atp2a2 positioning in the liver remained unaffected, with the majority of loci colocalizing with heterochromatin. These findings show that RNA polymerase II is redistributed to affect transcriptional programming and characterize for the first time the structural rearrangements in chromatin that underpin cardiac pathology.

scholarly journals The Role of RNA Polymerase II Contiguity and Long-Range Interactions in the Regulation of Gene Expression in Human Pluripotent Stem Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Livia Eiselleova ◽  
Viktor Lukjanov ◽  
Simon Farkas ◽  
David Svoboda ◽  
Karel Stepka ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Long Range ◽  
Pluripotent Stem Cells ◽  
Human Pluripotent Stem Cells ◽  
Transcription Factories ◽  
Long Range Interactions ◽  
Rnap Ii

The eukaryotic nucleus is a highly complex structure that carries out multiple functions primarily needed for gene expression, and among them, transcription seems to be the most fundamental. Diverse approaches have demonstrated that transcription takes place at discrete sites known as transcription factories, wherein RNA polymerase II (RNAP II) is attached to the factory and immobilized while transcribing DNA. It has been proposed that transcription factories promote chromatin loop formation, creating long-range interactions in which relatively distant genes can be transcribed simultaneously. In this study, we examined long-range interactions between the POU5F1 gene and genes previously identified as being POU5F1 enhancer-interacting, namely, CDYL, TLE2, RARG, and MSX1 (all involved in transcriptional regulation), in human pluripotent stem cells (hPSCs) and their early differentiated counterparts. As a control gene, RUNX1 was used, which is expressed during hematopoietic differentiation and not associated with pluripotency. To reveal how these long-range interactions between POU5F1 and the selected genes change with the onset of differentiation and upon RNAP II inhibition, we performed three-dimensional fluorescence in situ hybridization (3D-FISH) followed by computational simulation analysis. Our analysis showed that the numbers of long-range interactions between specific genes decrease during differentiation, suggesting that the transcription of monitored genes is associated with pluripotency. In addition, we showed that upon inhibition of RNAP II, long-range associations do not disintegrate and remain constant. We also analyzed the distance distributions of these genes in the context of their positions in the nucleus and revealed that they tend to have similar patterns resembling normal distribution. Furthermore, we compared data created in vitro and in silico to assess the biological relevance of our results.

Nutrient-regulated gene expression in eukaryotes

2006 ◽  
Vol 73 ◽  
pp. 85-96 ◽  
Author(s):  
Richard J. Reece ◽  
Laila Beynon ◽  
Stacey Holden ◽  
Amanda D. Hughes ◽  
Karine Rébora ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcriptional Control ◽  
Direct Interaction ◽  
Signalling Pathways ◽  
A Cell ◽  
One Step ◽  
Higher Eukaryotes ◽  
Regulated Gene Expression

The recognition of changes in environmental conditions, and the ability to adapt to these changes, is essential for the viability of cells. There are numerous well characterized systems by which the presence or absence of an individual metabolite may be recognized by a cell. However, the recognition of a metabolite is just one step in a process that often results in changes in the expression of whole sets of genes required to respond to that metabolite. In higher eukaryotes, the signalling pathway between metabolite recognition and transcriptional control can be complex. Recent evidence from the relatively simple eukaryote yeast suggests that complex signalling pathways may be circumvented through the direct interaction between individual metabolites and regulators of RNA polymerase II-mediated transcription. Biochemical and structural analyses are beginning to unravel these elegant genetic control elements.

scholarly journals Acute perturbation strategies in interrogating RNA polymerase II elongation factor function in gene expression

2021 ◽  
Vol 35 (3-4) ◽  
pp. 273-285
Author(s):  
Bin Zheng ◽  
Yuki Aoi ◽  
Avani P. Shah ◽  
Marta Iwanaszko ◽  
Siddhartha Das ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Elongation Factor ◽  
Factor Function

scholarly journals In vivo live imaging of RNA polymerase II transcription factories in primary cells

2013 ◽  
Vol 27 (7) ◽  
pp. 767-777 ◽  
Author(s):  
A. Ghamari ◽  
M. P. C. van de Corput ◽  
S. Thongjuea ◽  
W. A. van Cappellen ◽  
W. van IJcken ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Live Imaging ◽  
Primary Cells ◽  
Transcription Factories ◽  
Rna Polymerase Ii Transcription

The largest subunit of RNA polymerase II in Dictyostelium: conservation of the unique tail domain and gene expression

1992 ◽  
Vol 70 (9) ◽  
pp. 792-799 ◽  
Author(s):  
Tak Yee Lam ◽  
Lawrence Chan ◽  
Patrick Yip ◽  
Chi-Hung Siu
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Developmental Process ◽  
Developmental Regulation ◽  
Consensus Sequence ◽  
Protein Band ◽  
Tail Domain ◽  
Mrna Accumulation ◽  
Carboxyl Terminal

cDNAs encoding the largest subunit of RNA polymerase II were isolated from a Dictyostelium cDNA library. A total of 2.9 kilobases (kb) of cDNA was sequenced and the amino acid sequence of the carboxyl-terminal half of the protein was deduced. Similar to other eukaryotic RNA polymerases II, the largest subunit of Dictyostelium RNA polymerase II contains a unique repetitive tail domain at its carboxyl-terminal region. It consists of 24 highly conserved heptapeptide repeats, with a consensus sequence of Tyr-Ser-Pro-Thr-Ser-Pro-Ser. In addition to the tail domain, five segments of the deduced primary structure show > 50% sequence identity with either yeast or mouse protein. RNA blots show that cDNA probes hybridized with a single mRNA species of ~ 6 kb and immunoblots using a monoclonal antibody raised against the tail domain lighted up a single protein band of 200 kilodaltons. Interestingly, expression of the largest subunit of RNA polymerase II appears to be under developmental regulation. The accumulation of its mRNA showed a 60% increase during the first 3 h of development, followed by a steady decrease during the next 6 h. Cells began to accumulate a higher level of the RNA polymerase II mRNA after 9 h of development. When cells were treated with low concentrations of cAMP pulses to stimulate the developmental process, the pattern of mRNA accumulation moved 3 h ahead, but otherwise remained similar to that of control cells.Key words: RNA polymerase, cDNA, sequence homology, gene expression, Dictyostelium.

scholarly journals Heat Shock Protein Genes Undergo Dynamic Alteration in Their Three-Dimensional Structure and Genome Organization in Response to Thermal Stress

2017 ◽  
Vol 37 (24) ◽  
Author(s):  
Surabhi Chowdhary ◽  
Amoldeep S. Kainth ◽  
David S. Gross
Keyword(s):  
Thermal Stress ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Rna Polymerase Ii ◽  
De Novo ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Chromosome Conformation ◽  
Coding Regions ◽  
Response To Stress

ABSTRACT Three-dimensional (3D) chromatin organization is important for proper gene regulation, yet how the genome is remodeled in response to stress is largely unknown. Here, we use a highly sensitive version of chromosome conformation capture in combination with fluorescence microscopy to investigate Heat Shock Protein (HSP) gene conformation and 3D nuclear organization in budding yeast. In response to acute thermal stress, HSP genes undergo intense intragenic folding interactions that go well beyond 5′-3′ gene looping previously described for RNA polymerase II genes. These interactions include looping between upstream activation sequence (UAS) and promoter elements, promoter and terminator regions, and regulatory and coding regions (gene “crumpling”). They are also dynamic, being prominent within 60 s, peaking within 2.5 min, and attenuating within 30 min, and correlate with HSP gene transcriptional activity. With similarly striking kinetics, activated HSP genes, both chromosomally linked and unlinked, coalesce into discrete intranuclear foci. Constitutively transcribed genes also loop and crumple yet fail to coalesce. Notably, a missense mutation in transcription factor TFIIB suppresses gene looping, yet neither crumpling nor HSP gene coalescence is affected. An inactivating promoter mutation, in contrast, obviates all three. Our results provide evidence for widespread, transcription-associated gene crumpling and demonstrate the de novo assembly and disassembly of HSP gene foci.

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