scholarly journals RNA surveillance controls 3D genome structure via stable cohesin-chromosome interaction

2021 ◽  
Author(s):  
Yujin Chun ◽  
Sungwook Han ◽  
Taemook Kim ◽  
Yoonjung Choi ◽  
Daeyoup Lee

The 3D architecture that the genome is folded into is regulated by CTCF, which determines domain borders, and cohesin, which generates interactions within domains. However, organisms lacking CTCF have been reported to still have cohesin-mediated 3D structures with strong borders. How this can be achieved and precisely regulated are yet unknown. Using in situ Hi-C, we found that 3'-end RNA processing factors coupled with proper transcription termination are a cis-acting determinant that regulates the localization and dynamics of cohesin on the chromosome arms. Loss of RNA processing factors, including nuclear exosome and Pfs2, destabilizes cohesin from the 3'-ends of convergent genes and results in decreased cohesin-mediated domain boundaries. We observed the co-localization between Rad21 and a wide range of 3'end RNA processing/termination factors. Further, deletion of Rrp6 leads to cohesin redistribution to facultative heterochromatin, resulting in improper domain boundaries. Importantly, we observed that knockdown of Rrp6/Exosc10 caused a defect in cohesin binding and loss of local topologically associating domains (TADs) interactions in mouse embryonic stem cells. Based on these findings, we propose a novel function of the RNA surveillance pathway in 3D genome organization via cohesin complex, which provides the molecular basis underlying the dynamics of cohesin function.

2019 ◽  
Vol 19 (2) ◽  
pp. 71-82 ◽  
Author(s):  
Anne van Schoonhoven ◽  
Danny Huylebroeck ◽  
Rudi W Hendriks ◽  
Ralph Stadhouders

Abstract Chromosomes have a complex three-dimensional (3D) architecture comprising A/B compartments, topologically associating domains and promoter–enhancer interactions. At all these levels, the 3D genome has functional consequences for gene transcription and therefore for cellular identity. The development and activation of lymphocytes involves strict control of gene expression by transcription factors (TFs) operating in a three-dimensionally organized chromatin landscape. As lymphocytes are indispensable for tissue homeostasis and pathogen defense, and aberrant lymphocyte activity is involved in a wide range of human morbidities, acquiring an in-depth understanding of the molecular mechanisms that control lymphocyte identity is highly relevant. Here we review current knowledge of the interplay between 3D genome organization and transcriptional control during B and T lymphocyte development and antigen-dependent activation, placing special emphasis on the role of TFs.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Tejaswi Iyyanki ◽  
Baozhen Zhang ◽  
Qixuan Wang ◽  
Ye Hou ◽  
Qiushi Jin ◽  
...  

Abstract Muscle-invasive bladder cancers are characterized by their distinct expression of luminal and basal genes, which could be used to predict key clinical features such as disease progression and overall survival. Transcriptionally, FOXA1, GATA3, and PPARG are shown to be essential for luminal subtype-specific gene regulation and subtype switching, while TP63, STAT3, and TFAP2 family members are critical for regulation of basal subtype-specific genes. Despite these advances, the underlying epigenetic mechanisms and 3D chromatin architecture responsible for subtype-specific regulation in bladder cancer remain unknown. Result We determine the genome-wide transcriptome, enhancer landscape, and transcription factor binding profiles of FOXA1 and GATA3 in luminal and basal subtypes of bladder cancer. Furthermore, we report the first-ever mapping of genome-wide chromatin interactions by Hi-C in both bladder cancer cell lines and primary patient tumors. We show that subtype-specific transcription is accompanied by specific open chromatin and epigenomic marks, at least partially driven by distinct transcription factor binding at distal enhancers of luminal and basal bladder cancers. Finally, we identify a novel clinically relevant transcription factor, Neuronal PAS Domain Protein 2 (NPAS2), in luminal bladder cancers that regulates other subtype-specific genes and influences cancer cell proliferation and migration. Conclusion In summary, our work identifies unique epigenomic signatures and 3D genome structures in luminal and basal urinary bladder cancers and suggests a novel link between the circadian transcription factor NPAS2 and a clinical bladder cancer subtype.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peng-Fei Xu ◽  
Ricardo Moraes Borges ◽  
Jonathan Fillatre ◽  
Maraysa de Oliveira-Melo ◽  
Tao Cheng ◽  
...  

AbstractGenerating properly differentiated embryonic structures in vitro from pluripotent stem cells remains a challenge. Here we show that instruction of aggregates of mouse embryonic stem cells with an experimentally engineered morphogen signalling centre, that functions as an organizer, results in the development of embryo-like entities (embryoids). In situ hybridization, immunolabelling, cell tracking and transcriptomic analyses show that these embryoids form the three germ layers through a gastrulation process and that they exhibit a wide range of developmental structures, highly similar to neurula-stage mouse embryos. Embryoids are organized around an axial chordamesoderm, with a dorsal neural plate that displays histological properties similar to the murine embryo neuroepithelium and that folds into a neural tube patterned antero-posteriorly from the posterior midbrain to the tip of the tail. Lateral to the chordamesoderm, embryoids display somitic and intermediate mesoderm, with beating cardiac tissue anteriorly and formation of a vasculature network. Ventrally, embryoids differentiate a primitive gut tube, which is patterned both antero-posteriorly and dorso-ventrally. Altogether, embryoids provide an in vitro model of mammalian embryo that displays extensive development of germ layer derivatives and that promises to be a powerful tool for in vitro studies and disease modelling.


Author(s):  
Sarah Schleicher ◽  
Stefan Binder

Abstract Key message RNA PROCESSING FACTORs 1 AND 8 (RPF1 and RPF8), both restorer of fertility like pentatricopeptide repeat proteins, are required for processing of dicistronic nad4L-atp4 and nad3-rps12 transcripts in Arabidopsis mitochondria. Abstract In mitochondria of Arabidopsis thaliana (Arabidopsis), the 5′ termini of many RNAs are generated on the post-transcriptional level. This process is still poorly understood in terms of both the underlying mechanism as well as proteins required. Our studies now link the generation of polymorphic 5′ extremities of the dicistronic nad3-rps12 and nad4L-atp4 transcripts to the function of the P-type pentatricopeptide repeat proteins RNA PROCESSING FACTORs 8 (RPF8) and 1 (RPF1). RPF8 is required to generate the nad3-rps12 -141 5′ end in ecotype Van-0 whereas the RPF8 allele in Col has no function in the generation of any 5′ terminus of this transcript. This observation strongly suggests the involvement of an additional factor in the generation of the -229 5′ end of nad3-rps12 transcripts in Col. RPF1, previously found to be necessary for the generation of the -228 5′ end of the major 1538 nucleotide-long nad4 mRNAs, is also important for the formation of nad4L-atp4 transcripts with a 5′ end at position -318 in Col. Many Arabidopsis ecotypes contain inactive RPF1 alleles resulting in the accumulation of various low abundant nad4L-atp4 RNAs which might represent precursor and/or degradation products. Some of these ecotypes accumulate major, but slightly smaller RNA species. The introduction of RPF1 into these lines not only establishes the formation of the major nad4L-atp4 dicistronic mRNA with the -318 5′ terminus, the presence of this gene also suppresses the accumulation of most alternative nad4L-atp4 RNAs. Beside RPF1, several other factors contribute to nad4L-atp4 transcript formation.


2021 ◽  
Author(s):  
Masae Ohno ◽  
Tadashi Ando ◽  
David G. Priest ◽  
Yuichi Taniguchi

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Diana Buitrago ◽  
Mireia Labrador ◽  
Juan Pablo Arcon ◽  
Rafael Lema ◽  
Oscar Flores ◽  
...  

AbstractDetermining the effect of DNA methylation on chromatin structure and function in higher organisms is challenging due to the extreme complexity of epigenetic regulation. We studied a simpler model system, budding yeast, that lacks DNA methylation machinery making it a perfect model system to study the intrinsic role of DNA methylation in chromatin structure and function. We expressed the murine DNA methyltransferases in Saccharomyces cerevisiae and analyzed the correlation between DNA methylation, nucleosome positioning, gene expression and 3D genome organization. Despite lacking the machinery for positioning and reading methylation marks, induced DNA methylation follows a conserved pattern with low methylation levels at the 5’ end of the gene increasing gradually toward the 3’ end, with concentration of methylated DNA in linkers and nucleosome free regions, and with actively expressed genes showing low and high levels of methylation at transcription start and terminating sites respectively, mimicking the patterns seen in mammals. We also see that DNA methylation increases chromatin condensation in peri-centromeric regions, decreases overall DNA flexibility, and favors the heterochromatin state. Taken together, these results demonstrate that methylation intrinsically modulates chromatin structure and function even in the absence of cellular machinery evolved to recognize and process the methylation signal.


1994 ◽  
Vol 267 (5) ◽  
pp. L489-L497 ◽  
Author(s):  
S. W. Glasser ◽  
T. R. Korfhagen ◽  
S. E. Wert ◽  
J. A. Whitsett

This review summarizes progress in the application of transgenic mouse technology to the study of lung development and disease. Since advances in molecular genetics have greatly facilitated the isolation of cDNA and genes, our ability to readily assess roles of both normal and mutated genes in transgenic mouse in vivo represents a major advance, bridging molecular biology and whole animal physiology. Strategies have been developed in which lung epithelial cell promoter elements are used to drive normal or mutated genes into specific subsets of respiratory epithelial cells in the lungs of developing and mature transgenic mice. These mice have been used to elucidate the cis-acting elements controlling lung epithelial cell gene expression, to discern the role of specific polypeptides in lung morphogenesis and tumorigenesis, and to create animal models of pulmonary disease. The ability to mutate genes at their precise chromosomal locations through gene targeting in embryonic stem cells has lead to the production of animal models of lung diseases such as cystic fibrosis. Both gene insertion and gene targeting create permanent mouse lines that pass the modified gene to their progeny, providing animals for the study of the pathogenesis and treatment of pulmonary disorders.


2000 ◽  
Vol 129 (2-3) ◽  
pp. 241-251 ◽  
Author(s):  
Paul J. Mintz ◽  
David L. Spector

2000 ◽  
Vol 150 (2) ◽  
pp. F37-F44 ◽  
Author(s):  
Stephen M. Mount ◽  
Helen K. Salz

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