scholarly journals Incorporation of a nucleoside analog maps genome repair sites in postmitotic human neurons

Science ◽  
2021 ◽  
Vol 372 (6537) ◽  
pp. 91-94
Author(s):  
Dylan A. Reid ◽  
Patrick J. Reed ◽  
Johannes C. M. Schlachetzki ◽  
Ioana I. Nitulescu ◽  
Grace Chou ◽  
...  

Neurons are the longest-lived cells in our bodies and lack DNA replication, which makes them reliant on a limited repertoire of DNA repair mechanisms to maintain genome fidelity. These repair mechanisms decline with age, but we have limited knowledge of how genome instability emerges and what strategies neurons and other long-lived cells may have evolved to protect their genomes over the human life span. A targeted sequencing approach in human embryonic stem cell–induced neurons shows that, in neurons, DNA repair is enriched at well-defined hotspots that protect essential genes. These hotspots are enriched with histone H2A isoforms and RNA binding proteins and are associated with evolutionarily conserved elements of the human genome. These findings provide a basis for understanding genome integrity as it relates to aging and disease in the nervous system.

2020 ◽  
Author(s):  
Dylan A. Reid ◽  
Patrick J. Reed ◽  
Johannes C.M. Schlachetzki ◽  
Grace Chou ◽  
Sahaana Chandran ◽  
...  

AbstractNeurons are the longest-living cells in our bodies, becoming post-mitotic in early development upon terminal differentiation. Their lack of DNA replication makes them reliant on DNA repair mechanisms to maintain genome fidelity. These repair mechanisms decline with age, potentially giving rise to genomic dysfunction that may influence cognitive decline and neurodegenerative diseases. Despite this challenge, our knowledge of how genome instability emerges and what mechanisms neurons and other long-lived cells may have evolved to protect their genome integrity over the human life span is limited. Using a targeted sequencing approach, we demonstrate that neurons consolidate much of their DNA repair efforts into well-defined hotspots that protect genes that are essential for their identity and function. Our findings provide a basis to understand genome integrity as it relates to aging and disease in the nervous system.One Sentence SummaryRecurrent DNA repair hotspots in neurons are linked to genes essential for identity and function.


2020 ◽  
Vol 122 (5) ◽  
pp. 613-623 ◽  
Author(s):  
Aldo S. Bader ◽  
Ben R. Hawley ◽  
Ania Wilczynska ◽  
Martin Bushell

AbstractEffective DNA repair is essential for cell survival: a failure to correctly repair damage leads to the accumulation of mutations and is the driving force for carcinogenesis. Multiple pathways have evolved to protect against both intrinsic and extrinsic genotoxic events, and recent developments have highlighted an unforeseen critical role for RNA in ensuring genome stability. It is currently unclear exactly how RNA molecules participate in the repair pathways, although many models have been proposed and it is possible that RNA acts in diverse ways to facilitate DNA repair. A number of well-documented DNA repair factors have been described to have RNA-binding capacities and, moreover, screens investigating DNA-damage repair mechanisms have identified RNA-binding proteins as a major group of novel factors involved in DNA repair. In this review, we integrate some of these datasets to identify commonalities that might highlight novel and interesting factors for future investigations. This emerging role for RNA opens up a new dimension in the field of DNA repair; we discuss its impact on our current understanding of DNA repair processes and consider how it might influence cancer progression.


Author(s):  
Teresa Chioccarelli ◽  
Geppino Falco ◽  
Donato Cappetta ◽  
Antonella De Angelis ◽  
Luca Roberto ◽  
...  

AbstractCircular RNA (circRNA) biogenesis requires a backsplicing reaction, promoted by inverted repeats in cis-flanking sequences and trans factors, such as RNA-binding proteins (RBPs). Among these, FUS plays a key role. During spermatogenesis and sperm maturation along the epididymis such a molecular mechanism has been poorly explored. With this in mind, we chose circCNOT6L as a study case and wild-type (WT) as well as cannabinoid receptor type-1 knock-out (Cb1−/−) male mice as animal models to analyze backsplicing mechanisms. Our results suggest that spermatozoa (SPZ) have an endogenous skill to circularize mRNAs, choosing FUS as modulator of backsplicing and under CB1 stimulation. A physical interaction between FUS and CNOT6L as well as a cooperation among FUS, RNA Polymerase II (RNApol2) and Quaking (QKI) take place in SPZ. Finally, to gain insight into FUS involvement in circCNOT6L biogenesis, FUS expression was reduced through RNA interference approach. Paternal transmission of FUS and CNOT6L to oocytes during fertilization was then assessed by using murine unfertilized oocytes (NF), one-cell zygotes (F) and murine oocytes undergoing parthenogenetic activation (PA) to exclude a maternal contribution. The role of circCNOT6L as an active regulator of zygote transition toward the 2-cell-like state was suggested using the Embryonic Stem Cell (ESC) system. Intriguingly, human SPZ exactly mirror murine SPZ.


2018 ◽  
Author(s):  
Anna L. Mallam ◽  
Wisath Sae-Lee ◽  
Jeffrey M. Schaub ◽  
Fan Tu ◽  
Anna Battenhouse ◽  
...  

AbstractRNA-binding proteins (RBPs) play essential roles in biology and are frequently associated with human disease. While recent studies have systematically identified individual RBPs, their higher order assembly intoRibonucleoprotein (RNP) complexes has not been systematically investigated. Here, we describe a proteomics method for systematic identification of RNP complexes in human cells. We identify 1,428 protein complexes that associate with RNA, indicating that over 20% of known human protein complexes contain RNA. To explore the role of RNA in the assembly of each complex, we identify complexes that dissociate, change composition, or form stable protein-only complexes in the absence of RNA. Importantly, these data also provide specific novel insights into the function of well-studied protein complexes not previously known to associate with RNA, including replication factor C (RFC) and cytokinetic centralspindlin complex. Finally, we use our method to systematically identify cell-type specific RNA-associated proteins in mouse embryonic stem cells. We distribute these data as a resource, rna.MAP (rna.proteincomplexes.org) which provides a comprehensive dataset for the study of RNA-associated protein complexes. Our system thus provides a novel methodology for further explorations across human tissues and disease states, as well as throughout all domains of life.SummaryAn exploration of human protein complexes in the presence and absence of RNA reveals endogenous ribonucleoprotein complexes


2019 ◽  
Author(s):  
Isabelle Leticia Zaboroski Silva ◽  
Anny Waloski Robert ◽  
Guillermo Cabrera Cabo ◽  
Lucia Spangenberg ◽  
Marco Augusto Stimamiglio ◽  
...  

AbstractPosttranscriptional regulation plays a fundamental role in the biology of embryonic stem cells (ESCs). Many studies have demonstrated that multiple mRNAs are coregulated by one or more RNA binding proteins (RBPs) that orchestrate the expression of these molecules. A family of RBPs, known as PUF (Pumilio-FBF), is highly conserved among species and has been associated with the undifferentiated and differentiated states of different cell lines. In humans, two homologs of the PUF family have been found: Pumilio 1 (PUM1) and Pumilio 2 (PUM2). To understand the role of these proteins in human ESCs (hESCs), we first demonstrated the influence of the silencing of PUM1 and PUM2 on pluripotency genes. OCT4 and NANOG mRNA levels decreased significantly with the knockdown of Pumilio, suggesting that PUMILIO proteins play a role in the maintenance of pluripotency in hESCs. Furthermore, we observed that the hESCs silenced for PUM1 and 2 exhibited an improvement in efficiency of in vitro cardiomyogenic differentiation. Using in silico analysis, we identified mRNA targets of PUM1 and PUM2 expressed during cardiomyogenesis. With the reduction of PUM1 and 2, these target mRNAs would be active and could be involved in the progression of cardiomyogenesis.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sundararaghavan Pattabiraman ◽  
Gajendra Kumar Azad ◽  
Triana Amen ◽  
Shlomi Brielle ◽  
Jung Eun Park ◽  
...  

Abstract Vimentin is one of the first cytoplasmic intermediate filaments to be expressed in mammalian cells during embryogenesis, but its role in cellular fitness has long been a mystery. Vimentin is acknowledged to play a role in cell stiffness, cell motility, and cytoplasmic organization, yet it is widely considered to be dispensable for cellular function and organismal development. Here, we show that Vimentin plays a role in cellular stress response in differentiating cells, by recruiting aggregates, stress granules, and RNA-binding proteins, directing their elimination and asymmetric partitioning. In the absence of Vimentin, pluripotent embryonic stem cells fail to differentiate properly, with a pronounced deficiency in neuronal differentiation. Our results uncover a novel function for Vimentin, with important implications for development, tissue homeostasis, and in particular, stress response.


2017 ◽  
Vol 372 (1733) ◽  
pp. 20170021 ◽  
Author(s):  
Neil Brockdorff

Identifying the critical RNA binding proteins (RBPs) that elicit Xist mediated silencing has been a key goal in X inactivation research. Early studies implicated the Polycomb proteins, a family of factors linked to one of two major multiprotein complexes, PRC1 and PRC2 (Wang 2001 Nat. Genet. 28 , 371–375 ( doi:10.1038/ng574 ); Silva 2003 Dev. Cell 4 , 481–495 ( doi:10.1016/S1534-5807(03)00068-6 ); de Napoles 2004 Dev. Cell 7 , 663–676 ( doi:10.1016/j.devcel.2004.10.005 ); Plath 2003 Science 300 , 131–135 ( doi:10.1126/science.1084274 )). PRC1 and PRC2 complexes catalyse specific histone post-translational modifications (PTMs), ubiquitylation of histone H2A at position lysine 119 (H2AK119u1) and methylation of histone H3 at position lysine 27 (H3K27me3), respectively, and accordingly, these modifications are highly enriched over the length of the inactive X chromosome (Xi). A key study proposed that PRC2 subunits bind directly to Xist RNA A-repeat element, a region located at the 5′ end of the transcript known to be required for Xist mediated silencing (Zhao 2008 Science 322 , 750–756 ( doi:10.1126/science.1163045 )). Subsequent recruitment of PRC1 was assumed to occur via recognition of PRC2 mediated H3K27me3 by the CBX subunit of PRC1, as has been shown to be the case at other Polycomb target loci (Cao 2002 Science 298 , 1039–1043 ( doi:10.1126/science.1076997 )). More recently, several reports have questioned aspects of the prevailing view, both in relation to the mechanism for Polycomb recruitment by Xist RNA and the contribution of the Polycomb pathway to Xist mediated silencing. In this article I provide an overview of our recent progress towards resolving these discrepancies. This article is part of the themed issue ‘X-chromosome inactivation: a tribute to Mary Lyon’.


2019 ◽  
Author(s):  
Samudyata ◽  
Paulo P. Amaral ◽  
Pär G. Engström ◽  
Samuel C. Robson ◽  
Michael L. Nielsen ◽  
...  

AbstractSox2 is a master transcriptional regulator of embryonic development. In this study, we determined the protein interactome of Sox2 in the chromatin and nucleoplasm of mouse embryonic stem (mES) cells. Apart from canonical interactions with pluripotency-regulating transcription factors, we identified interactions with several chromatin modulators, including members of the heterochromatin protein 1 (HP1) family, suggesting a role of Sox2 in chromatin-mediated transcriptional repression. Sox2 was also found to interact with RNA binding proteins (RBPs), including proteins involved in RNA processing. RNA immunoprecipitation followed by sequencing revealed that Sox2 associates with different messenger RNAs, as well as small nucleolar RNA Snord34 and the non-coding RNA 7SK. 7SK has been shown to regulate transcription at regulatory regions, which could suggest a functional interaction with Sox2 for chromatin recruitment. Nevertheless, we found no evidence of Sox2 modulating recruitment of 7SK to chromatin when examining 7SK chromatin occupancy by Chromatin Isolation by RNA Purification (ChIRP) in Sox2 depleted mES cells. In addition, knockdown of 7SK in mES cells did not lead to any change in Sox2 occupancy at 7SK-regulated genes. Thus, our results show that Sox2 extensively interact with RBPs, and suggest that Sox2 and 7SK co-exist in a ribonucleoprotein complex whose function is not to regulate chromatin recruitment, but might rather regulate other processes in the nucleoplasm.Summary blurbSox2 interacts with RNA-binding proteins and diverse RNAs


2021 ◽  
Author(s):  
Bhaswatee Das ◽  
Bipasha Choudhury ◽  
Aditya Kumar ◽  
Vishwa Jyoti Baruah

Mutations in genome are essential for evolution but if the frequency of mutation increases it can evince to be detrimental, for a steady maintenance there exist a detailed complex system of surveillance and repair of DNA defects. Therefore, fault in DNA repair processes raises the probability of genomic instability and cancer in organisms. Genome instability encompasses various aspects of mutations from indels to various somatic variants. The chapter tries to present an overview of how cancer puts up several ways to ensure suppression of the fidelity in our DNA repair system. Cancer cells assure failure of efficient DNA repair mechanisms by innumerous ways, by mutation and epigenetic modifications in repair genes themselves or genes controlling their expression and functions, other by some catastrophic events like kataegis, chromothripsis and chromoplexy. These are clustered mutations taking place at a particular genomic locus which deluge the repair process. Cancer generation and evolution is dependent largely on genome instability, so it applies many strategies to overcome one of its basic obstacles that is DNA repair, targeting these DNA repair genes has also demonstrated to be helpful in cancer therapy; but an intricate understanding of recalcitrant process and mechanisms of drug resistant in cancer will further enhance the potential in them.


2021 ◽  
Vol 8 ◽  
Author(s):  
Julie A. Klaric ◽  
Stas Wüst ◽  
Stephanie Panier

DNA double-strand breaks (DSBs) are highly cytotoxic DNA lesions. To protect genomic stability and ensure cell homeostasis, cells mount a complex signaling-based response that not only coordinates the repair of the broken DNA strand but also activates cell cycle checkpoints and, if necessary, induces cell death. The last decade has seen a flurry of studies that have identified RNA-binding proteins (RBPs) as novel regulators of the DSB response. While many of these RBPs have well-characterized roles in gene expression, it is becoming increasingly clear that they also have non-canonical functions in the DSB response that go well beyond transcription, splicing and mRNA processing. Here, we review the current understanding of how RBPs are integrated into the cellular response to DSBs and describe how these proteins directly participate in signal transduction, amplification and repair at damaged chromatin. In addition, we discuss the implications of an RBP-mediated DSB response for genome instability and age-associated diseases such as cancer and neurodegeneration.


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