scholarly journals CRISPR-induced Expression of N-Terminally Truncated Dicer in Mouse Cells

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 540
Author(s):  
Radek Malik ◽  
Petr Svoboda
Keyword(s):  
Small Rnas ◽  
Mammalian Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Rnase Iii ◽  
Double Stranded Rna ◽  
Mouse Cells ◽  
Rnai Response ◽  
Rnai Activity ◽  
Specific Mrna

RNA interference (RNAi) designates sequence-specific mRNA degradation mediated by small RNAs generated from long double-stranded RNA (dsRNA) by RNase III Dicer. RNAi appears inactive in mammalian cells except for mouse oocytes, where high RNAi activity exists because of an N-terminally truncated Dicer isoform, denoted DicerO. DicerO processes dsRNA into small RNAs more efficiently than the full-length Dicer expressed in somatic cells. DicerO is expressed from an oocyte-specific promoter of retrotransposon origin, which is silenced in other cell types. In this work, we evaluated CRISPR-based strategies for epigenetic targeting of the endogenous Dicer gene to restore DicerO expression and, consequently, RNAi. We show that reactivation of DicerO expression can be achieved in mouse embryonic stem cells, but it is not sufficient to establish a robust canonical RNAi response.

scholarly journals Specific Double-Stranded RNA Interference in Undifferentiated Mouse Embryonic Stem Cells

2001 ◽  
Vol 21 (22) ◽  
pp. 7807-7816 ◽  
Author(s):  
Shicheng Yang ◽  
Stephen Tutton ◽  
Eric Pierce ◽  
Kyonggeun Yoon
Keyword(s):  
Gene Expression ◽  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Es Cells ◽  
Embryonic Stem ◽  
Transient Transfection ◽  
Interferon Response ◽  
Green Fluorescent Protein Gene ◽  
Double Stranded Rna ◽  
Rnai Activity

ABSTRACT Specific mRNA degradation mediated by double-stranded RNA (dsRNA) interference (RNAi) is a powerful way of suppressing gene expression in plants, nematodes, and fungal, insect, and protozoan systems. However, only a few cases of RNAi have been reported in mammalian systems. Here, we investigated the feasibility of the RNAi strategy in several mammalian cells by using the enhanced green fluorescent protein gene as a target, either by in situ production of dsRNA from transient transfection of a plasmid harboring a 547-bp inverted repeat or by direct transfection of dsRNA made by in vitro transcription. Several mammalian cells including differentiated embryonic stem (ES) cells did not exhibit specific RNAi in transient transfection. This long dsRNA, however, was capable of inducing a sequence-specific RNAi for the episomal and chromosomal target gene in undifferentiated ES cells. dsRNA at 8.3 nM decreased the cognate gene expression up to 70%. However, RNAi activity was not permanent because it was more pronounced in early time points and diminished 5 days after transfection. Thus, undifferentiated ES cells may lack the interferon response, similar to mouse embryos and oocytes. Regardless of their apparent RNAi activity, however, cytoplasmic extracts from mammalian cells produced a small RNA of 21 to 22 nucleotides from the long dsRNA. Our results suggest that mammalian cells may possess RNAi activity but nonspecific activation of the interferon response by longer dsRNA may mask the specific RNAi. The findings offer an opportunity to use dsRNA for inhibition of gene expression in ES cells to study differentiation.

scholarly journals E. coli OxyS non-coding RNA does not trigger RNAi in C. elegans

2014 ◽  
Author(s):  
Alper Akay ◽  
Peter Sarkies ◽  
Eric Alexander Miska
Keyword(s):  
Small Rnas ◽  
Biological Function ◽  
Rapid Development ◽  
Rnai Pathway ◽  
Regulate Gene Expression ◽  
Double Stranded Rna ◽  
E Coli ◽  
C Elegans ◽  
Non Coding Rna ◽  
Rnai Response

The discovery of RNA interference (RNAi) in C. elegans has had a major impact on scientific research, led to the rapid development of RNAi tools and has inspired RNA-based therapeutics. Astonishingly, nematodes, planaria and many insects take up double-stranded RNA (dsRNA) from their environment to elicit RNAi; the biological function of this mechanism is unclear. Recently, the E. coli OxyS non-coding RNA was shown to regulate gene expression in C. elegans when E. coli is offered as food. This was surprising given that C. elegans is unlikely to encounter E. coli in nature. To directly test the hypothesis that the E. coli OxyS non-coding RNA triggers the C. elegans RNAi pathway, we sequenced small RNAs from C. elegans after feeding with bacteria. We clearly demonstrate that the OxyS non-coding RNA does not trigger an RNAi response in C. elegans. We conclude that the biology of environmental RNAi remains to be discovered.

scholarly journals Isolation of cDNA clones for mouse cytoskeletal gamma-actin and differential expression of cytoskeletal actin mRNAs in mouse cells.

1988 ◽  
Vol 8 (9) ◽  
pp. 3929-3933 ◽  
Author(s):  
K Tokunaga ◽  
K Takeda ◽  
K Kamiyama ◽  
H Kageyama ◽  
K Takenaga ◽  
...  
Keyword(s):  
Differential Expression ◽  
Functional Diversity ◽  
Mammalian Cells ◽  
Cell Types ◽  
Regulatory Mechanisms ◽  
Untranslated Regions ◽  
Cdna Clones ◽  
Expression Levels ◽  
Mouse Tissues ◽  
Mouse Cells

We described the structures of mouse cytoskeletal gamma-actin cDNA clones and showed that there is strong conservation of the untranslated regions with human gamma-actin cDNA. In addition, we found that the expression levels of beta- and gamma-actin mRNAs are differentially controlled in various mouse tissues and cell types but are coordinately increased in the cellular growing state. These results suggest that there are multiple regulatory mechanisms of cytoskeletal actin genes and are consistent with the argument that beta- and gamma-actins might have functional diversity in mammalian cells.

EFFECTS OF ANAEROBIOSIS ON THE RATES OF MULTIPLICATION OF MAMMALIAN CELLS CULTURED IN VITRO

1960 ◽  
Vol 38 (1) ◽  
pp. 871-878 ◽  
Author(s):  
Samuel Dales
Keyword(s):  
Mammalian Cells ◽  
Glucose Utilization ◽  
Lactic Acid Production ◽  
Cell Types ◽  
In Vitro Cultures ◽  
Cell Multiplication ◽  
Embryonic Mouse ◽  
Mouse Cells ◽  
Oxidation Of Glucose

To test the effects of anaerobiosis on the rate of multiplication and carbohydrate metabolism of mammalian cells in vitro, cultures of a 'permanent' line, Earle's L strain cells, and of freshly explanted embryonic mouse cells were propagated in the presence and absence of oxygen. Contrary to the findings of several other investigators, our results show that the multiplication of both cell types was depressed by anaerobiosis. Anaerobiosis for at least 7 days, did not, however, bring about unbalanced growth in L cells, nor did it affect their capability to divide rapidly soon after they were returned to aerobic conditions. From the rates of glucose utilization, lactic acid production, and cell multiplication it was estimated that the rate of division in the two cell types studied was proportional to the energy which could be released from either glycolysis or complete oxidation of glucose.

scholarly journals Processing of DNA prior to illegitimate recombination in mouse cells.

1997 ◽  
Vol 17 (7) ◽  
pp. 3779-3785 ◽  
Author(s):  
G Henderson ◽  
J P Simons
Keyword(s):  
Homologous Recombination ◽  
Mammalian Cells ◽  
Embryonic Stem ◽  
Illegitimate Recombination ◽  
Strand Bias ◽  
Dna Breaks ◽  
Exogenous Dna ◽  
Double Strand Dna Breaks ◽  
Mouse Cells ◽  
Exonuclease Digestion

In mammalian cells, the predominant pathway of chromosomal integration of exogenous DNA is random or illegitimate recombination; integration by homologous recombination is infrequent. Homologous recombination is initiated at double-strand DNA breaks which have been acted on by single-strand exonuclease. To further characterize the relationship between illegitimate and homologous recombination, we have investigated whether illegitimate recombination is also preceded by exonuclease digestion. Heteroduplex DNAs which included strand-specific restriction markers at each of four positions were generated. These DNAs were introduced into mouse embryonic stem cells, and stably transformed clones were isolated and analyzed to determine whether there was any strand bias in the retention of restriction markers with respect to their positions. Some of the mismatches appear to have been resolved by mismatch repair. Very significant strand bias was observed in the retention of restriction markers, and there was polarity of marker retention between adjacent positions. We conclude that DNA is frequently subjected to 5'-->3' exonuclease digestion prior to integration by illegitimate recombination and that the length of DNA removed by exonuclease digestion can be extensive. We also provide evidence which suggests that frequent but less extensive 3'-->5' exonuclease processing also occurs.

scholarly journals Y-RNA and tRNA Cleavage by RNase L Mediates Terminal dsRNA Response

2016 ◽  
Author(s):  
Jesse Donovan ◽  
Sneha Rath ◽  
David Kolet-Mandrikov ◽  
Alexei Korennykh
Keyword(s):  
Small Rnas ◽  
Mammalian Cells ◽  
Innate Immune ◽  
Rna Cleavage ◽  
Rnase L ◽  
Rna Seq ◽  
Danger Signal ◽  
Double Stranded Rna ◽  
Transfer Rnas ◽  
Non Coding Rna

AbstractDouble-stranded RNA (dsRNA) is a danger signal that triggers endonucleolytic degradation of RNA inside infected and stressed mammalian cells. This mechanism inhibits growth and ultimately removes problematic cells via apoptosis. To elucidate the molecular functions of this program and understand the connection between RNA cleavage and programmed cell death, we visualized dsRNA-induced degradation of human small RNAs using RtcB ligase-assisted RNA sequencing (RtcB RNA-seq). RtcB RNA-seq revealed strong cleavage of select transfer RNAs (tRNAs) and autoantigenic Y-RNAs, and identified the innate immune receptor RNase L as the responsible endoribonuclease. RNase L cleaves the non-coding RNA (ncRNA) targets site-specifically, releasing abundant ncRNA fragments, and downregulating full-length tRNAs and Y-RNAs. The depletion of a single Y-RNA, RNY1, appears particularly important and the loss of this Y-RNA is sufficient to initiate apoptosis. Site-specific cleavage of small ncRNA by RNase L thus emerges as an important terminal step in dsRNA surveillance.

scholarly journals MicroRNA-deficient mouse embryonic stem cells acquire a functional interferon response

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jeroen Witteveldt ◽  
Lisanne I Knol ◽  
Sara Macias
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Mammalian Cells ◽  
Viral Infections ◽  
Embryonic Stem ◽  
Cell Types ◽  
Interferon Response ◽  
Central Component ◽  
Type I ◽  
Antiviral Mechanism

When mammalian cells detect a viral infection, they initiate a type I interferon (IFNs) response as part of their innate immune system. This antiviral mechanism is conserved in virtually all cell types, except for embryonic stem cells (ESCs) and oocytes which are intrinsically incapable of producing IFNs. Despite the importance of the IFN response to fight viral infections, the mechanisms regulating this pathway during pluripotency are still unknown. Here we show that, in the absence of miRNAs, ESCs acquire an active IFN response. Proteomic analysis identified MAVS, a central component of the IFN pathway, to be actively silenced by miRNAs and responsible for suppressing IFN expression in ESCs. Furthermore, we show that knocking out a single miRNA, miR-673, restores the antiviral response in ESCs through MAVS regulation. Our findings suggest that the interaction between miR-673 and MAVS acts as a switch to suppress the antiviral IFN during pluripotency and present genetic approaches to enhance their antiviral immunity.

scholarly journals Main constraints for RNAi induced by expressed long dsRNA in mouse cells

2018 ◽  
Author(s):  
Tomas Demeter ◽  
Michaela Vaskovicova ◽  
Radek Malik ◽  
Filip Horvat ◽  
Josef Pasulka ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Interferon Response ◽  
Protein Kinase R ◽  
Positive Effects ◽  
Dsrna Binding ◽  
Mouse Cells ◽  
Dicer Cleavage ◽  
Microrna Pathway ◽  
Microrna Function ◽  
Specific Mrna

RNA interference (RNAi) is sequence-specific mRNA degradation guided by small RNAs (siRNAs) produced from long double-stranded RNA (dsRNA) by RNase Dicer. Proteins executing RNAi are present in mammalian cells but sustain a gene-regulating microRNA pathway while dsRNA-induced innate immunity relies on a sequence-independent interferon response. While striving to benchmark mammalian RNAi analysis, we report that the main RNAi constraint is siRNA production, which integrates Dicer activity, dsRNA structure, and siRNA targeting efficiency. Unexpectedly, increased expression of dsRNA-binding Dicer co-factors TARBP2 or PACT reduces RNAi but not microRNA function. Elimination of Protein Kinase R, a key dsRNA sensor for interferon response, had minimal positive effects in fibroblasts. Without increasing Dicer activity, RNAi can occur when the first Dicer cleavage of an abundant dsRNA produces an efficient siRNA. In mammals, efficient RNAi may effectively employ substrates, which have some features of microRNA precursors, hence bringing the two pathways mechanistically even closer. At the same time, Dicer substrate optimization, which viruses would avoid, represents an opportunity for evolving RNAi, yet unlikely as an antiviral system.

scholarly journals Ogt-Dependent X-Chromosome-Linked Protein Glycosylation Is a Requisite Modification in Somatic Cell Function and Embryo Viability

2004 ◽  
Vol 24 (4) ◽  
pp. 1680-1690 ◽  
Author(s):  
Niall O'Donnell ◽  
Natasha E. Zachara ◽  
Gerald W. Hart ◽  
Jamey D. Marth
Keyword(s):  
Somatic Cell ◽  
Mammalian Cells ◽  
Cell Function ◽  
Embryonic Stem ◽  
Cell Types ◽  
Protein Glycosylation ◽  
Embryo Viability ◽  
Altered Expression ◽  
T Cell Apoptosis

ABSTRACT The Ogt gene encodes a glycosyltransferase that links N-acetylglucosamine to serine and threonine residues (O-GlcNAc) on nuclear and cytosolic proteins. Efforts to study a mammalian model of Ogt deficiency have been hindered by the requirement for this X-linked gene in embryonic stem cell viability, necessitating the use of conditional mutagenesis in vivo. We have extended these observations by segregating Ogt mutation to distinct somatic cell types, including neurons, thymocytes, and fibroblasts, the latter by an approach developed for inducible Ogt mutagenesis. We show that Ogt mutation results in the loss of O-GlcNAc and causes T-cell apoptosis, neuronal tau hyperphosphorylation, and fibroblast growth arrest with altered expression of c-Fos, c-Jun, c-Myc, Sp1, and p27. We further segregated the mutant Ogt allele to parental gametes by oocyte- and spermatid-specific Cre-loxP mutagenesis. By this we established an in vivo genetic approach that supports the ontogeny of female heterozygotes bearing mutant X-linked genes required during embryogenesis. Successful production and characterization of such female heterozygotes further indicates that mammalian cells commonly require a functional Ogt allele. We find that O-GlcNAc modulates protein phosphorylation and expression among essential and conserved cell signaling pathways.

scholarly journals A Sweet Potion to Put Embryonic Stem Cells to Sleep

2009 ◽  
Vol 9 ◽  
pp. 236-249 ◽  
Author(s):  
Kaushik D. Deb
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Mammalian Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Intercellular Transport ◽  
Ambient Temperatures ◽  
Naturally Occurring ◽  
Therapeutic Properties ◽  
Temperature Storage

Human embryonic stem cells (hESCs) are rapidly revolutionizing the areas of drug screening and therapy. In view of their applications and high operational costs at global multicentric setups, the ability to store and transport hESCs and derivatives under ambient temperatures, and their cryopreservation without compromising the stemness, function, and viability, is becoming imperative. Here we discuss the need for a natural cryoprotectant and biopreservative with a potential to improve cryopreservation, ambient temperature storage, and shipping of hESCs and derivatives. Trehalose, a naturally occurring disaccharide with therapeutic properties, protects the integrity of cells against desiccation, dehydration, and extreme heat or cold, and has been successfully tested for some somatic stem cell types. However, the biggest setback is the inability of mammalian cells to internalize trehalose. Here we review the methods being developed at different laboratories to facilitate its intercellular transport and advocate the need for similar advances in hESCs.

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