Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 44
Filtrar
1.
Materials (Basel) ; 17(9)2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38730757

RESUMO

The aim of the work was to investigate the influence of the surface texture of composite based on PA6, intended for wet painting, on the stability of the colour and gloss parameters. The stability of the paint coating was required to be maintained despite exposure to mechanical stress resulting from attempts to manually remove graffiti stains. The study examined the influence of surface texture on the effectiveness of cleaning. In the case of painted surfaces from which graffiti stains were effectively removed, the roughness, colour parameters and gloss of the paint coating were measured. During the research, it was found that roughness after painting decreased to the value of Ra < 2.00 µm meets aesthetic expectations and at the same time ensures the effective removal of graffiti stains. For this surface, there were no negative effects of the mechanical impact on the textures or quality parameters of the coating as a result of manual graffiti removal. As a result of the conducted research, the recommended maximum values of roughness and textures of the surfaces to be painted were determined in order to ensure a sufficiently low amount of work necessary to effectively remove traces of graffiti.

2.
BMC Plant Biol ; 23(1): 623, 2023 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-38057711

RESUMO

Although most of the genes encoding tRNAs in plants are dispersed throughout the genome, a fraction of them form tRNA gene clusters. In Arabidopsis thaliana, the smallest of tRNA clusters on chromosome 5 consists of four tRNA-Cys-GCA genes placed within repeating units of 0.4 kbp. A systematic analysis of the genomic sequences of syntenic regions from various ecotypes of A. thaliana showed that the general structure of the cluster, consisting of a tRNA-Cys pseudogene followed by repeating units containing tRNA-Cys genes, is well conserved. However, there is significant heterogeneity in the number of repeating units between different ecotypes. A unique feature of this cluster is the presence of putative transposable elements (Helitron). In addition, two further tRNA-Cys gene mini-clusters (gene pairs) in A. thaliana were identified. RNA-seq-based evaluation of expression of tRNA-Cys-GCA genes showed a positive signal for 11 out of 13 unique transcripts. An analysis of the conservation of the tRNA-Cys clusters from A. thaliana with the corresponding regions from four other Arabidopsis species suggests a sequence of events that led to the divergence of these regions.


Assuntos
Arabidopsis , Arabidopsis/genética , Sequência de Bases , Genoma , RNA de Transferência/genética , Família Multigênica
3.
Front Neurol ; 13: 884519, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35865644

RESUMO

Background: Symptomatic intracranial hemorrhage (sICH) and malignant brain edema (MBE) are well-known deleterious endovascular treatment (EVT) complications that some studies found to be associated with postprocedural blood pressure (BP) variability. We aimed to evaluate their association with periprocedural BP changes, including its intraprocedural decrease. Methods: We retrospectively analyzed the data of 132 consecutive patients that underwent EVT between 1 December 2018 and 31 December 2019, for anterior circulation ischemic stroke. Analyzed predictors of sICH and MBE included non-invasively obtained BP before and 5-min after treatment, intraprocedural relative decreases of BP from baseline, and its post-treatment increases. SICH was defined in accordance with the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST) criteria and MBE as brain edema with midline shift on the follow-up imaging. We used binary logistic regression analysis to investigate the association of BP parameters and the incidence of sICH and MBE. Results: Among the included patients, 11 (8.3%) developed sICH and 31 (23.5%) MBE. The intraprocedural decrease of mean arterial blood pressure (MAP) was independently associated with MBE occurrence (aOR per 10 mmHg drop from baseline 1.27; 95% CI 1.01-1.60; P = 0.040). Over 40% MAP drop was associated with a higher risk of sICH in the entire cohort (aOR 4.24; 95% CI 1.33-13.51; P = 0.015), but not in the subgroup with successful reperfusion (aOR 2.81; 95% CI 0.64-12.23; P = 0.169). Post-treatment systolic blood pressure (SBP) and MAP elevation above their minimal values during MT are significantly associated with the development of sICH (aOR per 10 mmHg SBP increase 1.78; 95% CI 1.15-2.76; P = 0.010 and aOR per 10 mmHg MAP increase 1.78; 95% CI 1.04-3.03; P = 0.035). Conclusions: In the anterior circulation ischemic stroke patients relative MAP decrease during EVT is associated with a higher risk of MBE occurrence, and over 40% MAP drop with a higher incidence of both MBE and sICH. Post-treatment elevation of SBP and MAP increased the risk of sICH.

4.
Gigascience ; 122022 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-37589306

RESUMO

BACKGROUND: One of the most effective and useful methods to explore the content of biological databases is searching with nucleotide or protein sequences as a query. However, especially in the case of nucleic acids, due to the large volume of data generated by the next-generation sequencing (NGS) technologies, this approach is often not available. The hierarchical organization of the NGS records is primarily designed for browsing or text-based searches of the information provided in metadata-related keywords, limiting the efficiency of database exploration. FINDINGS: We developed an automated pipeline that incorporates the well-established NGS data-processing tools and procedures to allow easy and effective sampling of the NCBI SRA database records. Given a file with query nucleotide sequences, our tool estimates the matching content of SRA accessions by probing only a user-defined fraction of a record's sequences. Based on the selected parameters, it allows performing a full mapping experiment with records that meet the required criteria. The pipeline is designed to be easy to operate-it offers a fully automatic setup procedure and is fixed on tested supporting tools. The modular design and implemented usage modes allow a user to scale up the analyses into complex computational infrastructure. CONCLUSIONS: We present an easy-to-operate and automated tool that expands the way a user can access and explore the information contained within the records deposited in the NCBI SRA database.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Metadados , Sequência de Aminoácidos , Bases de Dados Factuais , Nucleotídeos
5.
Eur J Trauma Emerg Surg ; 47(3): 803-809, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31740996

RESUMO

BACKGROUND: The purpose of this study was to compare the cumulative incidence of postoperative periprosthetic fracture (PPF) in a cohort of femoral neck fracture (FNF) patients treated with two commonly used cemented stems: either a collarless, polished, tapered Exeter stem or the anatomic Lubinus SP2 stem. METHODS: In this retrospective multicenter cohort study of a consecutive series of patients, we included 2528 patients of age 60 years and above with an FNF who were treated with either hemiarthroplasty or total hip arthroplasty using either a polished tapered Exeter stem or an anatomic Lubinus SP2 stem. The incidence of PPF was assessed at a minimum of 2 years postoperatively. RESULTS: The incidence of PPF was assessed at a median follow-up of 47 months postoperatively. Thirty nine patients (1.5%) sustained a PPF at a median of 27 months (range 0-96 months) postoperatively. Two of the operatively treated fractures were Vancouver A (5%), 7 were Vancouver B1 (18%), 10 were Vancouver B2 (26%), 7 were Vancouver B3 (18%), and 13 were Vancouver C (32%). The cumulative incidence of PPF was 2.3% in the Exeter group compared with 0.7% in the SP2 group (p < 0.001). The HR was 5.4 (95% CI 2.4-12.5, p < 0.001), using the SP2 group as the denominator. CONCLUSIONS: The Exeter stem was associated with a higher risk for PPF than the Lubinus SP2 stem. We suggest that the tapered Exeter stem should be used with caution in the treatment of FNF. TRIAL REGISTRATION: The study was registered at clinicaltrials.gov (identifier: NCT03326271).


Assuntos
Artroplastia de Quadril , Fraturas do Fêmur , Fraturas do Quadril , Prótese de Quadril , Fraturas Periprotéticas , Artroplastia de Quadril/efeitos adversos , Estudos de Coortes , Fraturas do Fêmur/cirurgia , Fraturas do Quadril/cirurgia , Prótese de Quadril/efeitos adversos , Humanos , Pessoa de Meia-Idade , Fraturas Periprotéticas/epidemiologia , Fraturas Periprotéticas/cirurgia , Desenho de Prótese , Reoperação , Estudos Retrospectivos
6.
Biochem Biophys Res Commun ; 520(3): 514-519, 2019 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-31610915

RESUMO

The recently discovered group of noncoding RNAs, which are fragments of tRNA molecules (tRFs), has not been fully characterized and its potential functions still require investigation. Porcine tRFs were characterized and compared to mouse and human tRFs. Two tRFs, 5' 32-33 nt and 3' 41-42 nt that are derived from the mature tRNAVal(CAC) and tRNAGly(GCC) were detected with the use of bioinformatics and the Northern blot method. The abundance of these tRFs in the case of Sus scrofa is restricted to the ovary and the kidney. The same tRFs were found in human cancer cells and in mouse sperm, circulating blood and its serum. The binding of selected sncRNAs (piRNA, 5'tRFVal(CAC) and miRNA) to the overexpressed PAZ domain of the PIWIL4 protein was also studied. It is noteworthy that porcine 5'tRFVal(CAC) and human 5'tRFVal(CAC)as well as 5'tRFGly(GCC) are bound to the PIWIL4 protein. The potential role of the analyzed tRFs in the development of mammals is also discussed.


Assuntos
Mamíferos/crescimento & desenvolvimento , Mamíferos/genética , RNA de Transferência/genética , Sus scrofa/crescimento & desenvolvimento , Sus scrofa/genética , Animais , Proteínas Argonautas/química , Proteínas Argonautas/genética , Proteínas Argonautas/metabolismo , Sequência Conservada , Evolução Molecular , Feminino , Humanos , Masculino , Mamíferos/metabolismo , Camundongos , MicroRNAs/genética , Modelos Moleculares , Conformação de Ácido Nucleico , Ligação Proteica , Domínios Proteicos , Estrutura Terciária de Proteína , RNA Interferente Pequeno/genética , Pequeno RNA não Traduzido/química , Pequeno RNA não Traduzido/genética , Pequeno RNA não Traduzido/metabolismo , RNA de Transferência/química , RNA de Transferência/metabolismo , Proteínas de Ligação a RNA , Especificidade da Espécie , Sus scrofa/metabolismo
7.
Cells ; 8(6)2019 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-31200566

RESUMO

We address here organellar genetic regulation and intercompartment genome coordination. We developed earlier a strategy relying on a tRNA-like shuttle to mediate import of nuclear transgene-encoded custom RNAs into mitochondria in plants. In the present work, we used this strategy to drive trans-cleaving hammerhead ribozymes into the organelles, to knock down specific mitochondrial RNAs and analyze the regulatory impact. In a similar approach, the tRNA mimic was used to import into mitochondria in Arabidopsis thaliana the orf77, an RNA associated with cytoplasmic male sterility in maize and possessing sequence identities with the atp9 mitochondrial RNA. In both cases, inducible expression of the transgenes allowed to characterise early regulation and signaling responses triggered by these respective manipulations of the organellar transcriptome. The results imply that the mitochondrial transcriptome is tightly controlled by a "buffering" mechanism at the early and intermediate stages of plant development, a control that is released at later stages. On the other hand, high throughput analyses showed that knocking down a specific mitochondrial mRNA triggered a retrograde signaling and an anterograde nuclear transcriptome response involving a series of transcription factor genes and small RNAs. Our results strongly support transcriptome coordination mechanisms within the organelles and between the organelles and the nucleus.


Assuntos
Mitocôndrias/genética , Desenvolvimento Vegetal/genética , Transcriptoma/genética , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Sequência de Bases , Núcleo Celular/genética , Regulação para Baixo/genética , Regulação da Expressão Gênica de Plantas , RNA Catalítico/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Mitocondrial/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Nicotiana/genética , Nicotiana/crescimento & desenvolvimento , Regulação para Cima/genética
8.
RNA Biol ; 15(6): 726-738, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29561243

RESUMO

The Arabidopsis GUT15 RNA belongs to a class of noncoding RNAs that are expressed from the intergenic regions of protein-coding genes. We show that the RNA polymerase II transcribed GUT15 transcript serves as a precursor for two stable RNA species, a tRNA-like molecule and GUT15-tRF-F5, which are both encoded by the final intron in the GUT15 gene. The GUT15-encoded tRNA-like molecule cannot be autonomously transcribed by RNA polymerase III. However, this molecule contains a CCA motif, suggesting that it may enter the tRNA maturation pathway. The GUT15-encoded tRNA-like sequence has an inhibiting effect on the splicing of its host intron. Moreover, we demonstrate that the canonical tRNA genes nested within introns do not affect the splicing patterns of their host protein-coding transcripts.


Assuntos
Arabidopsis , Conformação de Ácido Nucleico , RNA de Plantas , RNA de Transferência , RNA não Traduzido , Transcrição Gênica/fisiologia , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , RNA de Transferência/genética , RNA de Transferência/metabolismo , RNA não Traduzido/genética , RNA não Traduzido/metabolismo
9.
Plant Cell Physiol ; 59(1): e1, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29145635

RESUMO

tRNA-derived fragments (tRFs) constitute a new class of short regulatory RNAs that are a product of nascent or mature tRNA processing. tRF sequences have been identified in all domains of life; however, most published research pertains to human, yeast and some bacterial organisms. Despite growing interest in plant tRFs and accumulating evidence of their function in plant development and stress responses, no public, web-based repository dedicated to these molecules is currently available. Here, we introduce tRex (http://combio.pl/trex)-the first comprehensive data-driven online resource specifically dedicated to tRFs in the model plant Arabidopsis thaliana. The portal is based on verified Arabidopsis tRNA annotation and includes in-house-generated and publicly available small RNA sequencing experiments from various tissues, ecotypes, genotypes and stress conditions. The provided web-based tools are designed in a user-friendly manner and allow for seamless exploration of the data that are presented in the form of dynamic tables and cumulative coverage profiles. The tRex database is connected to external genomic and citation resources, which makes it a one-stop solution for Arabidopsis tRF-related research.


Assuntos
Arabidopsis/genética , Biologia Computacional/métodos , Bases de Dados Genéticas , RNA de Plantas/genética , RNA de Transferência/genética , Sequência de Bases , Internet , Conformação de Ácido Nucleico , RNA de Plantas/química , RNA de Transferência/química , Análise de Sequência de RNA/métodos , Homologia de Sequência do Ácido Nucleico
10.
Postepy Biochem ; 64(1): 55-66, 2018 Jun 30.
Artigo em Polonês | MEDLINE | ID: mdl-30652837

RESUMO

Different scientific disciplines such as physics, genetics or biochemistry crossed over into molecular biology in the last century. The Polish state didn't existed at the beginning of XX century, but the territory for a large number of scientists was not a limitation in delineating new routes, making fundamental discoveries or training the new generation of distinguished people of sciences. We want to tell the story of roots of molecular biology from the Polish perspective and outline its importance, by bringing closer the most essential discoveries of elite scientists in different fields of life science, associated with Poland and its territory.


Assuntos
Disciplinas das Ciências Biológicas/história , Biologia Molecular/história , História do Século XX , Polônia
11.
Biochim Biophys Acta Gen Subj ; 1861(11 Pt A): 2674-2679, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28713021

RESUMO

In December of 1966 the last nucleotide triplet in the genetic code has been assigned (Brenner et al., 1967 [1]) thus completing years of studies aimed at deciphering the nature of the relationship between the sequences of genes and proteins. The end product, the table of the genetic code, was a crowning achievement of the quest to unravel the basic mechanisms underlying functioning of all living organisms on the molecular level.


Assuntos
Código Genético/genética , Genética/história , Proteínas/genética , Sequência de Aminoácidos/genética , História do Século XX , Humanos
12.
Nucleic Acids Res ; 45(D1): D128-D134, 2017 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-27794554

RESUMO

RNAcentral is a database of non-coding RNA (ncRNA) sequences that aggregates data from specialised ncRNA resources and provides a single entry point for accessing ncRNA sequences of all ncRNA types from all organisms. Since its launch in 2014, RNAcentral has integrated twelve new resources, taking the total number of collaborating database to 22, and began importing new types of data, such as modified nucleotides from MODOMICS and PDB. We created new species-specific identifiers that refer to unique RNA sequences within a context of single species. The website has been subject to continuous improvements focusing on text and sequence similarity searches as well as genome browsing functionality. All RNAcentral data is provided for free and is available for browsing, bulk downloads, and programmatic access at http://rnacentral.org/.


Assuntos
Bases de Dados de Ácidos Nucleicos , RNA não Traduzido/química , Animais , Genômica , Humanos , Nucleotídeos/química , Análise de Sequência de RNA , Especificidade da Espécie
13.
Acta Biochim Pol ; 63(4): 841-844, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27878141

RESUMO

In eukaryotes, ribosomal 5S rRNAs are products of multigene families organized within clusters of tandemly repeated units. Accumulation of genomic data obtained from a variety of organisms demonstrated that the potential 5S rRNA coding sequences show a large number of variants, often incompatible with folding into a correct secondary structure. Here, we present results of an analysis of a large set of short RNA sequences generated by the next generation sequencing techniques, to address the problem of heterogeneity of the 5S rRNA transcripts in Arabidopsis and identification of potentially functional rRNA-derived fragments.


Assuntos
Arabidopsis/genética , RNA de Plantas/genética , RNA Ribossômico 5S/genética , Sequência de Bases , Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Sequências Repetidas Invertidas , Análise de Sequência de RNA , Homologia de Sequência do Ácido Nucleico
14.
Nucleic Acids Res ; 44(D1): D180-3, 2016 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-26490961

RESUMO

Ribosomal 5S RNA (5S rRNA) is the ubiquitous RNA component found in the large subunit of ribosomes in all known organisms. Due to its small size, abundance and evolutionary conservation 5S rRNA for many years now is used as a model molecule in studies on RNA structure, RNA-protein interactions and molecular phylogeny. 5SRNAdb (http://combio.pl/5srnadb/) is the first database that provides a high quality reference set of ribosomal 5S RNAs (5S rRNA) across three domains of life. Here, we give an overview of new developments in the database and associated web tools since 2002, including updates to database content, curation processes and user web interfaces.


Assuntos
Bases de Dados de Ácidos Nucleicos , RNA Ribossômico 5S/química , RNA Ribossômico 5S/genética , Eucariotos/genética , Conformação de Ácido Nucleico , RNA Arqueal/química , RNA Arqueal/genética , RNA Bacteriano/química , RNA Bacteriano/genética
15.
Biochem J ; 471(1): 53-66, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26209679

RESUMO

Despite great progress in the treatment of AIDS, HIV-1 remains one of the major concerns as a human pathogen. One of the therapeutic strategies against viral infections is the application of catalytic ribonucleic acids (ribozymes) that can significantly reduce expression of a target gene by site-specific hydrolysis of its mRNA. In the present paper, we report a study on the activity of several variants of hammerhead ribozymes targeting a conserved region within mRNA encoding HIV-1 envelope glycoprotein gp41. On the basis of the data from in vitro assays and gene silencing in the cultured cells, we propose a new hammerhead ribozyme targeting the gp41-encoding sequence that can be potentially used as a therapeutic agent in AIDS treatment. Moreover, we demonstrate that the hydrolytic activity of the ribozyme in the intracellular environment cannot be inferred solely from the results of in vitro experiments.


Assuntos
Regulação Viral da Expressão Gênica , Inativação Gênica , Proteína gp41 do Envelope de HIV/biossíntese , HIV-1/metabolismo , RNA Catalítico/metabolismo , Síndrome da Imunodeficiência Adquirida/genética , Síndrome da Imunodeficiência Adquirida/metabolismo , Síndrome da Imunodeficiência Adquirida/terapia , Proteína gp41 do Envelope de HIV/genética , HIV-1/genética , Células HeLa , Humanos , RNA Catalítico/genética
16.
Methods Mol Biol ; 1265: 227-54, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25634279

RESUMO

Genetic transformation of mitochondria in multicellular eukaryotes has remained inaccessible, hindering fundamental investigations and applications to gene therapy or biotechnology. In this context, we have developed a strategy to target nuclear transgene-encoded RNAs into mitochondria in plants. We describe here mitochondrial targeting of trans-cleaving ribozymes destined to knockdown organelle RNAs for regulation studies and inverse genetics and biotechnological purposes. The design and functional assessment of chimeric RNAs combining the ribozyme and the mitochondrial shuttle are detailed, followed by all procedures to prepare constructs for in vivo expression, generate stable plant transformants, and establish target RNA knockdown in mitochondria.


Assuntos
Mitocôndrias/genética , Mitocôndrias/metabolismo , RNA Catalítico/genética , Expressão Gênica , Técnicas de Silenciamento de Genes , Células Vegetais , Interferência de RNA , Transporte de RNA , RNA Catalítico/metabolismo , Transformação Genética , Transgenes
17.
Plant Mol Biol ; 83(3): 191-204, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23708952

RESUMO

It is becoming increasingly evident that the RNA degradome is a crucial component of the total cellular RNA pool. Here, we present an analysis of the medium-sized RNAs (midi RNAs) that form in Arabidopsis thaliana. Our analyses revealed that the midi RNA fraction contained mostly 20-70-nt-long fragments derived from various RNA species, including tRNA, rRNA, mRNA and snRNA. The majority of these fragments could be classified as stable RNA degradation intermediates (RNA degradants). Using two dimensional polyacrylamide gel electrophoresis, we demonstrated that high copy number RNA (hcn RNA) degradants appear in plant cells not only during stress, as it was earlier suggested. They are continuously produced also under physiological conditions. The data collected indicated that the accumulation pattern of the hcn RNA degradants is organ-specific and can be affected by various endogenous and exogenous factors. In addition, we demonstrated that selected degradants efficiently inhibit translation in vitro. Thus, the results of our studies suggest that hcn RNA degradants are likely to be involved in the regulation of gene expression in plants.


Assuntos
Arabidopsis/genética , Dosagem de Genes , Estabilidade de RNA , RNA de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas , Hidrólise
18.
PLoS One ; 8(1): e54741, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23382952

RESUMO

In this manuscript we describe for the first time mirror image catalytic nucleic acids (Spiegelzymes), which hydrolyze sequence specifically L-ribonucleic acid molecules. The mirror image nucleic acid ribozymes designed are based upon the known hammerhead ribozyme and DNAzyme structures that contain L-ribose or L-deoxyribose instead of the naturally occurring D-ribose or D-deoxyribose, respectively. Both Spiegelzymes show similar hydrolytic activities with the same L-RNA target molecules and they also exhibit extra ordinary stabilities when tested with three different human sera. In this respect they are very similar to Spiegelmers (mirror image aptamers), which we had previously developed and for which it has been shown that they are non-toxic and non-immunogenic. Since we are also able to demonstrate that the hammerhead and DNAzyme Spiegelzymes can also hydrolyze mirror image oligonucleotide sequences, like they occur in Spiegelmers, in vivo, it seems reasonable to assume that Spiegelzymes may in principle be used as an antidote against Spiegelmers. Since the Spiegelzymes contain the same building blocks as the Spiegelmers, it can be expected that they will have similar favorable biological characteristics concerning toxicity and immunogenety. In trying to understand the mechanism of action of the Spiegelzymes described in this study, we have initiated for the first time a model building system with L-nucleic acids. The models for L-hammerhead ribozyme and L-DNAzyme interaction with the same L-RNA target will be presented.


Assuntos
DNA Catalítico/metabolismo , RNA Catalítico/metabolismo , RNA/metabolismo , Animais , Sequência de Bases , Células COS , Chlorocebus aethiops , DNA Catalítico/sangue , DNA Catalítico/química , Desoxirribonucleases/metabolismo , Humanos , Hidrólise , Modelos Moleculares , Conformação de Ácido Nucleico , RNA/química , Estabilidade de RNA , RNA Catalítico/sangue , RNA Catalítico/química , Ribonucleases/metabolismo
19.
Biochem J ; 451(3): 439-51, 2013 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-23418809

RESUMO

Hammerhead ribozyme is a versatile tool for down-regulation of gene expression in vivo. Owing to its small size and high activity, it is used as a model for RNA structure-function relationship studies. In the present paper we describe a new extended hammerhead ribozyme HH-2 with a tertiary stabilizing motif constructed on the basis of the tetraloop receptor sequence. This ribozyme is very active in living cells, but shows low activity in vitro. To understand it, we analysed tertiary structure models of substrate-ribozyme complexes. We calculated six unique catalytic core geometry parameters as distances and angles between particular atoms that we call the ribozyme fingerprint. A flanking sequence and tertiary motif change the geometry of the general base, general acid, nucleophile and leaving group. We found almost complete correlation between these parameters and the decrease of target gene expression in the cells. The tertiary structure model calculations allow us to predict ribozyme intracellular activity. Our approach could be widely adapted to characterize catalytic properties of other RNAs.


Assuntos
RNA Catalítico/química , Animais , Domínio Catalítico , Células HeLa , Humanos , Sequências Repetidas Invertidas , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , RNA Catalítico/genética , RNA Catalítico/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Tubarões/metabolismo , Relação Estrutura-Atividade , Transfecção
20.
Biochim Biophys Acta ; 1824(2): 334-8, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22064121

RESUMO

The crystal structure of the ribosome inhibiting protein Mistletoe Lectin I (ML-I) derived from the European mistletoe, Viscum album, in complex with kinetin has been refined at 2.7Å resolution. Suitably large crystals of ML-I were obtained applying the counter diffusion method using the Gel Tube R Crystallization Kit (GT-R) on board the Russian Service Module on the international space station ISS within the GCF mission No. 6, arranged by the Japanese aerospace exploration agency (JAXA). Hexagonal bi-pyramidal crystals were grown during three months under microgravity. Before data collection the crystals were soaked in a saturated solution of kinetin and diffraction data to 2.7Å were collected using synchrotron radiation and cryogenic techniques. The atomic model was refined and revealed a single kinetin molecule in the ribosome inactivation site of ML-I. The complex demonstrates the feasibility of mistletoe to bind plant hormones out of the host regulation system as part of a self protection mechanism.


Assuntos
Cinetina/química , Reguladores de Crescimento de Plantas/química , Proteínas Inativadoras de Ribossomos Tipo 2/química , Toxinas Biológicas/química , Viscum album/metabolismo , Domínio Catalítico , Cristalização/métodos , Cristalografia por Raios X , Modelos Moleculares , Complexos Multiproteicos/química , Ligação Proteica , Conformação Proteica , Ausência de Peso
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...