Enzymatic and Physical Studies on the Triplex dTn∙dAn∙rUn

1973 ◽  
Vol 51 (4) ◽  
pp. 436-449 ◽  
Author(s):  
Nancy L. Murray ◽  
A. Richard Morgan
Keyword(s):  
Buoyant Density ◽  
Minor Groove ◽  
Model System ◽  
Rational Approach ◽  
Major Groove ◽  
Dna And Rna ◽  
Pancreatic Rnase ◽  
Mixing Curves ◽  
Transcription And Replication

The triplex dTn∙dAn∙rUn was studied as a model system both enzymatically and physically with a view that a rational approach for attempting to isolate triplexes from in vivo situations might emerge. The triplex was characterized by mixing curves and by its equilibrium buoyant density. In 5 mM Na phosphate, pH 7.3, for KCl concentrations below 0.4 M the triplex dissociated into dTn∙dAn + rUn, dissociation being complete at about 0.3 M KCl. If MgCl2 replaced KCl a strongly cooperative dissociation occurred at 1 mM MgCl2. Whereas with alkaline titration of dTn∙dAn∙rUn, rUn was dissociated first followed by dTn∙dAn, acidic titration resulted in the whole triplex dissociating together. Both transcription and replication of dTn∙dAn were strongly inhibited by formation of a triplex. The DNA and RNA moieties in the triplex are somewhat protected against DNase I and pancreatic RNase degradation, when compared with duplex dTn∙dAn or rUn. Spermine binds equally well to dTn∙dAn and dTn∙dAn∙rUn which is consistent with spermine binding in the minor groove and RNA in the major groove of DNA.

Existence of DNA in yeast microbodies

1978 ◽  
Vol 36 (2) ◽  
pp. 232-233
Author(s):  
Masako Osumi ◽  
Misuzu Nagano ◽  
Hiroko Kazama
Keyword(s):  
Catalase Activity ◽  
Buoyant Density ◽  
Model System ◽  
Contour Length ◽  
Native State ◽  
Normal Alkane ◽  
Remarkable Increase ◽  
Dna Molecule ◽  
Mitochondrial Dnas

We have found that microbodies appeared profusely together with a remarkable increase in catalase activity in normal alkane-grown cells of hydrocarbon-utilizing Candida yeasts, and that the microbodies multiplied by division in these cells. These features of Candida yeasts seem to provide a useful model system for studies on the biogenesis of the microbody. Subsequently, we have succeeded in isolation of Candida microbodies in an apparently native state, as judged biochemically and morphologically. The presence of DNA in the purified microbody fraction thus obtained was proved by the diphenylamine method. DNA molecule of about 15 urn in contour length was released from an isolated microbody. The physicochemical analyses of the microbody DNA revealed that its buoyant density differed from nuclear and mitochondrial DNAs. All these results lead us to the possibility that there is a novel type of DNA in microbodies.

scholarly journals Seminal Plasma: Relevant for Fertility?

2021 ◽  
Vol 22 (9) ◽  
pp. 4368
Author(s):  
Heriberto Rodriguez-Martinez ◽  
Emilio A. Martinez ◽  
Juan J. Calvete ◽  
Fernando J. Peña Vega ◽  
Jordi Roca
Keyword(s):  
Seminal Plasma ◽  
Current Knowledge ◽  
Inorganic Ions ◽  
Vitro Fertilization ◽  
Dna And Rna ◽  
Model Animal ◽  
Sexual Glands ◽  
Species Specific

Seminal plasma (SP), the non-cellular component of semen, is a heterogeneous composite fluid built by secretions of the testis, the epididymis and the accessory sexual glands. Its composition, despite species-specific anatomical peculiarities, consistently contains inorganic ions, specific hormones, proteins and peptides, including cytokines and enzymes, cholesterol, DNA and RNA—the latter often protected within epididymis- or prostate-derived extracellular vesicles. It is beyond question that the SP participates in diverse aspects of sperm function pre-fertilization events. The SP also interacts with the various compartments of the tubular genital tract, triggering changes in gene function that prepares for an eventual successful pregnancy; thus, it ultimately modulates fertility. Despite these concepts, it is imperative to remember that SP-free spermatozoa (epididymal or washed ejaculated) are still fertile, so this review shall focus on the differences between the in vivo roles of the SP following semen deposition in the female and those regarding additions of SP on spermatozoa handled for artificial reproduction, including cryopreservation, from artificial insemination to in vitro fertilization. This review attempts, including our own results on model animal species, to critically summarize the current knowledge of the reproductive roles played by SP components, particularly in our own species, which is increasingly affected by infertility. The ultimate goal is to reconcile the delicate balance between the SP molecular concentration and their concerted effects after temporal exposure in vivo. We aim to appraise the functions of the SP components, their relevance as diagnostic biomarkers and their value as eventual additives to refine reproductive strategies, including biotechnologies, in livestock models and humans.

scholarly journals Spatiotemporally programmable cascade hybridization of hairpin DNA in polymeric nanoframework for precise siRNA delivery

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Feng Li ◽  
Wenting Yu ◽  
Jiaojiao Zhang ◽  
Yuhang Dong ◽  
Xiaohui Ding ◽  
...  
Keyword(s):  
Steric Effect ◽  
Sirna Delivery ◽  
Dna Nanotechnology ◽  
Hybridization Chain Reaction ◽  
Dna Nanostructures ◽  
Chain Reaction ◽  
Dna Hairpins ◽  
In Vivo Experiments ◽  
Dna And Rna

AbstractDNA nanostructures have been demonstrated as promising carriers for gene delivery. In the carrier design, spatiotemporally programmable assembly of DNA under nanoconfinement is important but has proven highly challenging due to the complexity–scalability–error of DNA. Herein, a DNA nanotechnology-based strategy via the cascade hybridization chain reaction (HCR) of DNA hairpins in polymeric nanoframework has been developed to achieve spatiotemporally programmable assembly of DNA under nanoconfinement for precise siRNA delivery. The nanoframework is prepared via precipitation polymerization with Acrydite-DNA as cross-linker. The potential energy stored in the loops of DNA hairpins can overcome the steric effect in the nanoframework, which can help initiate cascade HCR of DNA hairpins and achieve efficient siRNA loading. The designer tethering sequence between DNA and RNA guarantees a triphosadenine triggered siRNA release specifically in cellular cytoplasm. Nanoframework provides stability and ease of functionalization, which helps address the complexity–scalability–error of DNA. It is exemplified that the phenylboronate installation on nanoframework enhanced cellular uptake and smoothed the lysosomal escape. Cellular results show that the siRNA loaded nanoframework down-regulated the levels of relevant mRNA and protein. In vivo experiments show significant therapeutic efficacy of using siPLK1 loaded nanoframework to suppress tumor growth.

scholarly journals Base-edited CAR T cells for combinational therapy against T cell malignancies

Leukemia ◽  
2021 ◽  
Author(s):  
Christos Georgiadis ◽  
Jane Rasaiyaah ◽  
Soragia Athina Gkazi ◽  
Roland Preece ◽  
Aniekan Etuk ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Specific Binding ◽  
Base Editing ◽  
Car T Cells ◽  
Dna And Rna ◽  
Car T ◽  
T Cell Malignancies

AbstractTargeting T cell malignancies using chimeric antigen receptor (CAR) T cells is hindered by ‘T v T’ fratricide against shared antigens such as CD3 and CD7. Base editing offers the possibility of seamless disruption of gene expression of problematic antigens through creation of stop codons or elimination of splice sites. We describe the generation of fratricide-resistant T cells by orderly removal of TCR/CD3 and CD7 ahead of lentiviral-mediated expression of CARs specific for CD3 or CD7. Molecular interrogation of base-edited cells confirmed elimination of chromosomal translocations detected in conventional Cas9 treated cells. Interestingly, 3CAR/7CAR co-culture resulted in ‘self-enrichment’ yielding populations 99.6% TCR−/CD3−/CD7−. 3CAR or 7CAR cells were able to exert specific cytotoxicity against leukaemia lines with defined CD3 and/or CD7 expression as well as primary T-ALL cells. Co-cultured 3CAR/7CAR cells exhibited highest cytotoxicity against CD3 + CD7 + T-ALL targets in vitro and an in vivo human:murine chimeric model. While APOBEC editors can reportedly exhibit guide-independent deamination of both DNA and RNA, we found no problematic ‘off-target’ activity or promiscuous base conversion affecting CAR antigen-specific binding regions, which may otherwise redirect T cell specificity. Combinational infusion of fratricide-resistant anti-T CAR T cells may enable enhanced molecular remission ahead of allo-HSCT for T cell malignancies.

scholarly journals Exposure of ichnovirus particles to digitonin leads to enhanced infectivity and induces fusion from without in an in vitro model system

2007 ◽  
Vol 88 (11) ◽  
pp. 2977-2984 ◽  
Author(s):  
Don Stoltz ◽  
Renée Lapointe ◽  
Andrea Makkay ◽  
Michel Cusson
Keyword(s):  
Outer Membrane ◽  
In Vitro Model ◽  
Model System ◽  
Host Cells ◽  
Fusion Event ◽  
Susceptible Host ◽  
In Vitro Model System ◽  
Vitro Model

Unlike most viruses, the mature ichnovirus particle possesses two unit membrane envelopes. Following loss of the outer membrane in vivo, nucleocapsids are believed to gain entry into the cytosol via a membrane fusion event involving the inner membrane and the plasma membrane of susceptible host cells; accordingly, experimentally induced damage to the outer membrane might be expected to increase infectivity. Here, in an attempt to develop an in vitro model system for studying ichnovirus infection, we show that digitonin-induced disruption of the virion outer membrane not only increases infectivity, but also uncovers an activity not previously associated with any polydnavirus: fusion from without.

scholarly journals Decontamination of surgical instruments from prions. II. In vivo findings with a model system for testing the removal of scrapie infectivity from steel surfaces

2008 ◽  
Vol 89 (1) ◽  
pp. 348-358 ◽  
Author(s):  
Karin Lemmer ◽  
Martin Mielke ◽  
Christine Kratzel ◽  
Marion Joncic ◽  
Muhsin Oezel ◽  
...  
Keyword(s):  
Model System ◽  
Surgical Instruments ◽  
Steel Surfaces

Human RecQ helicases in transcription-associated stress management: bridging the gap between DNA and RNA metabolism

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Tulika Das ◽  
Surasree Pal ◽  
Agneyo Ganguly
Keyword(s):  
Genome Integrity ◽  
Complex Structures ◽  
Huge Number ◽  
Dna Helicases ◽  
Dna Structures ◽  
Recq Helicases ◽  
Dna And Rna ◽  
Cellular Dna ◽  
Almost All ◽  
Transcription And Replication

Abstract RecQ helicases are a highly conserved class of DNA helicases that play crucial role in almost all DNA metabolic processes including replication, repair and recombination. They are able to unwind a wide variety of complex intermediate DNA structures that may result from cellular DNA transactions and hence assist in maintaining genome integrity. Interestingly, a huge number of recent reports suggest that many of the RecQ family helicases are directly or indirectly involved in regulating transcription and gene expression. On one hand, they can remove complex structures like R-loops, G-quadruplexes or RNA:DNA hybrids formed at the intersection of transcription and replication. On the other hand, emerging evidence suggests that they can also regulate transcription by directly interacting with RNA polymerase or recruiting other protein factors that may regulate transcription. This review summarizes the up to date knowledge on the involvement of three human RecQ family proteins BLM, WRN and RECQL5 in transcription regulation and management of transcription associated stress.

Sign in / Sign up

Export Citation Format

Share Document