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1.
J Appl Microbiol ; 132(4): 2694-2704, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34856035

RESUMO

AIMS: We described the presence of Helicobacter pylori (HP) and estimated the prevalence of primary and secondary resistance using molecular detection in gastric biopsies of Ecuadorian patients. METHODS AND RESULTS: 66.7% (238/357) of the patients demonstrated the presence of HP using CerTest qPCR. Of these, 69.79% (104/149) were without previous HP eradication treatment and 64.42% (134/208) with prior HP eradication treatment. The mutation-associated resistance rate for clarithromycin was 33.64% (primary resistance) and 32.82% (secondary resistance), whereas that in levofloxacin the primary and secondary resistance was 37.38% and 42%, respectively. For tetracycline and rifabutin, primary and secondary resistance was 0%. Primary and secondary resistance for metronidazole and amoxicillin could not be evaluated by genotypic methods (PCR and sequencing). CONCLUSIONS: The analysis of mutations in gyrA, 23S rRNA and 16S rRNA is useful to detect bacterial resistance as a guide for eradication therapy following failure of the first-line regimen. SIGNIFICANCE AND IMPACT OF THE STUDY: This study carried out in an Ecuadorian population indicates that the resistance of HP to first-line antibiotics is high, which may contribute to the high rates of treatment failure, and other treatment alternatives should be considered.


Assuntos
Infecções por Helicobacter , Helicobacter pylori , Amoxicilina/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana/genética , Equador , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/epidemiologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Humanos , Metronidazol/farmacologia , Metronidazol/uso terapêutico , Testes de Sensibilidade Microbiana , Mutação , RNA Ribossômico 16S
2.
NAR Genom Bioinform ; 2(4): lqaa080, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33575626

RESUMO

The small nucleolar RNAs (snoRNAs), essential for ribosome biogenesis, constitute a major family of medium-size noncoding RNAs (mncRNAs) in all eukaryotes. We present here, for the first time in a marine unicellular alga, the characterization of the snoRNAs family in Ostreococcus tauri, the smallest photosynthetic eukaryote. Using a transcriptomic approach, we identified 131 O. tauri snoRNAs (Ot-snoRNA) distributed in three classes: the C/D snoRNAs, the H/ACA snoRNAs and the MRP RNA. Their genomic organization revealed a unique combination of both the intronic organization of animals and the polycistronic organization of plants. Remarkably, clustered genes produced Ot-snoRNAs with unusual structures never previously described in plants. Their abundances, based on quantification of reads and northern blots, showed extreme differences in Ot-snoRNA accumulation, mainly determined by their differential stability. Most of these Ot-snoRNAs were predicted to target rRNAs or snRNAs. Seventeen others were orphan Ot-snoRNAs that would not target rRNA. These were specific to O. tauri or Mamiellophyceae and could have functions unrelated to ribosome biogenesis. Overall, these data reveal an 'evolutionary response' adapted to the extreme compactness of the O. tauri genome that accommodates the essential Ot-snoRNAs, developing multiple strategies to optimize their coordinated expression with a minimal cost on regulatory circuits.

3.
Biol Open ; 5(7): 942-54, 2016 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-27334696

RESUMO

Although the DEAD-box RNA helicase family is ubiquitous in eukaryotes, its developmental role remains unelucidated. Here, we report that cooperative action between the Arabidopsis nucleolar protein RH10, an ortholog of human DEAD-box RNA helicase DDX47, and the epigenetic repressor complex of ASYMMETRIC-LEAVES1 (AS1) and AS2 (AS1-AS2) is critical to repress abaxial (ventral) genes ETT/ARF3 and ARF4, which leads to adaxial (dorsal) development in leaf primordia at shoot apices. Double mutations of rh10-1 and as2 (or as1) synergistically up-regulated the abaxial genes, which generated abaxialized filamentous leaves with loss of the adaxial domain. DDX47 is part of the small subunit processome (SSUP) that mediates rRNA biogenesis. In rh10-1 we found various defects in SSUP-related events, such as: accumulation of 35S/33S rRNA precursors; reduction in the 18S/25S ratio; and nucleolar hypertrophy. Double mutants of as2 with mutations of genes that encode other candidate SSUP-related components such as nucleolin and putative rRNA methyltransferase exhibited similar synergistic defects caused by up-regulation of ETT/ARF3 and ARF4 These results suggest a tight link between putative SSUP and AS1-AS2 in repression of the abaxial-determining genes for cell fate decisions for adaxial development.

4.
BMC Genomics ; 16: 1009, 2015 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-26607788

RESUMO

BACKGROUND: In the past few decades, non-coding RNAs (ncRNAs) have emerged as important regulators of gene expression in eukaryotes. Most studies of ncRNAs in plants have focused on the identification of silencing microRNAs (miRNAs) and small interfering RNAs (siRNAs). Another important family of ncRNAs that has been well characterized in plants is the small nucleolar RNAs (snoRNAs) and the related small Cajal body-specific RNAs (scaRNAs). Both target chemical modifications of ribosomal RNAs (rRNAs) and small nuclear RNAs (snRNAs). In plants, the snoRNA genes are organized in clusters, transcribed by RNA Pol II from a common promoter and subsequently processed into mature molecules. The promoter regions of snoRNA polycistronic genes in plants are highly enriched in two conserved cis-regulatory elements (CREs), Telo-box and Site II, which coordinate the expression of snoRNAs and ribosomal protein coding genes throughout the cell cycle. RESULTS: In order to identify novel ncRNA genes, we have used the snoRNA Telo-box/Site II motifs combination as a functional promoter indicator to screen the Arabidopsis genome. The predictions generated by this process were tested by detailed exploration of available RNA-Seq and expression data sets and experimental validation. As a result, we have identified several snoRNAs, scaRNAs and 'orphan' snoRNAs. We also show evidence for 16 novel ncRNAs that lack similarity to any reported RNA family. Finally, we have identified two dicistronic genes encoding precursors that are processed to mature snoRNA and miRNA molecules. We discuss the evolutionary consequences of this result in the context of a tight link between snoRNAs and miRNAs in eukaryotes. CONCLUSIONS: We present an alternative computational approach for non-coding RNA detection. Instead of depending on sequence or structure similarity in the whole genome screenings, we have explored the properties of promoter regions of well-characterized ncRNAs. Interestingly, besides expected ncRNAs predictions we were also able to recover single precursor arrangement for snoRNA-miRNA. Accompanied by analyses performed on rice sequences, we conclude that such arrangement might have interesting functional and evolutionary consequences and discuss this result in the context of a tight link between snoRNAs and miRNAs in eukaryotes.


Assuntos
Arabidopsis/genética , MicroRNAs/genética , Regiões Promotoras Genéticas , RNA Nucleolar Pequeno/genética , RNA não Traduzido/genética , Sequência de Bases , Sítios de Ligação , Biologia Computacional/métodos , Ordem dos Genes , MicroRNAs/química , Conformação de Ácido Nucleico , Motivos de Nucleotídeos , Interferência de RNA , RNA Nucleolar Pequeno/química , RNA não Traduzido/química , Sequências Reguladoras de Ácido Nucleico
5.
Plant Cell ; 26(3): 1330-44, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24668745

RESUMO

In plants as well as in animals, hundreds to thousands of 45S rRNA gene copies localize in Nucleolus Organizer Regions (NORs), and the activation or repression of specific sets of rDNA depends on epigenetic mechanisms. Previously, we reported that the Arabidopsis thaliana nucleolin protein NUC1, an abundant and evolutionarily conserved nucleolar protein in eukaryotic organisms, is required for maintaining DNA methylation levels and for controlling the expression of specific rDNA variants in Arabidopsis. Interestingly, in contrast with animal or yeast cells, plants contain a second nucleolin gene. Here, we report that Arabidopsis NUC1 and NUC2 nucleolin genes are both required for plant growth and survival and that NUC2 disruption represses flowering. However, these genes seem to be functionally antagonistic. In contrast with NUC1, disruption of NUC2 induces CG hypermethylation of rDNA and NOR association with the nucleolus. Moreover, NUC2 loss of function triggers major changes in rDNA spatial organization, expression, and transgenerational stability. Our analyses indicate that silencing of specific rRNA genes is mostly determined by the active or repressed state of the NORs and that nucleolin proteins play a key role in the developmental control of this process.


Assuntos
Arabidopsis/genética , Cromatina/metabolismo , DNA Ribossômico/genética , Duplicação Gênica , Fosfoproteínas/genética , RNA Ribossômico/genética , Proteínas de Ligação a RNA/genética , Variações do Número de Cópias de DNA , Metilação de DNA , Genes de Plantas , Regiões Promotoras Genéticas , Nucleolina
6.
Plant J ; 65(5): 807-19, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21261762

RESUMO

In all eukaryotes, C/D small nucleolar ribonucleoproteins (C/D snoRNPs) are essential for methylation and processing of ribosomal RNAs. They consist of a box C/D small nucleolar RNA (C/D snoRNA) associated with four highly conserved nucleolar proteins. Recent data in HeLa cells and yeast have revealed that assembly of these snoRNPs is directed by NUFIP protein and other auxiliary factors. Nevertheless, the precise function and biological importance of NUFIP and the other assembly factors remains unknown. In plants, few studies have focused on RNA methylation and snoRNP biogenesis. Here, we identify and characterise the AtNUFIP gene that directs assembly of C/D snoRNP. To elucidate the function of AtNUFIP in planta, we characterized atnufip mutants. These mutants are viable but have severe developmental phenotypes. Northern blot analysis of snoRNA accumulation in atnufip mutants revealed a specific degradation of C/D snoRNAs and this situation is correlated with a reduction in rRNA methylation. Remarkably, the impact of AtNUFIP depends on the structure of snoRNA genes: it is essential for the accumulation of those C/D snoRNAs encoded by polycistronic genes, but not by monocistronic or tsnoRNA genes. We propose that AtNUFIP controls the kinetics of C/D snoRNP assembly on nascent precursors to overcome snoRNA degradation of aberrant RNPs. Finally, we show that AtNUFIP has broader RNP targets, controlling the accumulation of scaRNAs that direct methylation of spliceosomal snRNA in Cajal bodies.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Processamento Pós-Transcricional do RNA , RNA Ribossômico/química , RNA Nucleolar Pequeno/genética , Ribonucleoproteínas Nucleolares Pequenas/metabolismo , Sequência de Aminoácidos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Perfilação da Expressão Gênica , Teste de Complementação Genética , Metilação , Dados de Sequência Molecular , Mutagênese Insercional , Mutação , Fenótipo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Estabilidade de RNA , RNA de Plantas/química , RNA de Plantas/genética , RNA de Plantas/metabolismo , RNA Nucleolar Pequeno/metabolismo , Ribonucleoproteínas Nucleolares Pequenas/genética , Alinhamento de Sequência
7.
Plant Cell Physiol ; 51(12): 2119-31, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21062869

RESUMO

Here we report on the characterization of rice osa-miR827 and its two target genes, OsSPX-MFS1 and OsSPX-MFS2, which encode SPX-MFS proteins predicted to be implicated in phosphate (Pi) sensing or transport. We first show by Northern blot analysis that osa-miR827 is strongly induced by Pi starvation in both shoots and roots. Hybridization of osa-miR827 in situ confirms its strong induction by Pi starvation, with signals concentrated in mesophyll, epidermis and ground tissues of roots. In parallel, we analyzed the responses of the two OsSPX-MFS1 and OsSPX-MFS2 gene targets to Pi starvation. OsSPX-MFS1 mRNA is mainly expressed in shoots under sufficient Pi supply while its expression is reduced on Pi starvation, revealing a direct relationship between induction of osa-miR827 and down-regulation of OsSPX-MFS1. In contrast, OsSPX-MFS2 responds in a diametrically opposed manner to Pi starvation. The accumulation of OsSPX-MFS2 mRNA is dramatically enhanced under Pi starvation, suggesting the involvement of complex regulation of osa-miR827 and its two target genes. We further produced transgenic rice lines overexpressing osa-miR827 and T-DNA knockout mutant lines in which the expression of osa-miR827 is abolished. Compared with wild-type controls, both target mRNAs exhibit similar changes, their expression being reduced and increased in overexpressing and knockout lines, respectively. This suggests that OsSPX-MFS1 and OsSPX-MFS2 are both negatively regulated by osa-miR827 abundance although they respond differently to external Pi conditions. We propose that this is a complex mechanism comprising fine tuning of spatial or temporal regulation of both targets by osa-miR827.


Assuntos
Regulação da Expressão Gênica de Plantas , MicroRNAs/fisiologia , Oryza/genética , Fosfatos/deficiência , RNA de Plantas/genética , Adaptação Fisiológica , DNA Bacteriano , Genes de Plantas , Oryza/citologia , Oryza/metabolismo , Fosfatos/metabolismo , Raízes de Plantas/genética , Brotos de Planta/genética , Plantas Geneticamente Modificadas/citologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Transporte de RNA , RNA Mensageiro/genética , Deleção de Sequência , Estresse Fisiológico , Transcrição Gênica
8.
Biochem Soc Trans ; 38(2): 672-6, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20298241

RESUMO

The snoRNAs (small nucleolar RNAs) and related scaRNAs (small RNAs in the Cajal bodies) represent a major class of nuclear RNAs that guide 2'-O-ribose methylation and pseudouridylation of rRNAs, snRNAs (small nuclear RNAs) and other RNA targets. In vivo, all snoRNAs associate with a set of four highly conserved nucleolar proteins, forming the functional snoRNPs (small nucleolar ribonucleoproteins). The core structure of these mature snoRNPs has now been well described in eukaryotes, but less is known of their biogenesis. Recent data in animals and yeast reveal that assembly of the snoRNPs is a complex process that implicates several auxiliary proteins and transient protein-protein interactions. This new level of snoRNP regulation is now beginning to be unravelled in animals and yeast, but remains unexplored in plants. In the present paper, we review recent data from genomic and functional analysis allowing the identification and study of factors controlling the biogenesis of plant snoRNPs and their impact on plant development.


Assuntos
Plantas/genética , Ribonucleoproteínas Nucleolares Pequenas/genética , Ribonucleoproteínas Nucleolares Pequenas/fisiologia , Animais , Nucléolo Celular/genética , Nucléolo Celular/metabolismo , Corpos Enovelados/metabolismo , Corpos Enovelados/fisiologia , Sequência Conservada , Variação Genética , Modelos Biológicos , Plantas/metabolismo , Ribonucleoproteínas Nucleolares Pequenas/metabolismo
9.
Plant J ; 61(3): 383-98, 2010 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-19891704

RESUMO

We report on the structural characterization of a functional U3 snoRNA ribonucleoprotein complex isolated from Brassica oleracea. The BoU3 snoRNP complex (formerly NF D) binds ribosomal DNA (rDNA), specifically cleaves pre-rRNA at the primary cleavage site in vitro and probably links transcription to early pre-rRNA processing in vivo. Using a proteomic approach we have identified 62 proteins in the purified BoU3 snoRNP fraction, including small RNA associated proteins (Fibrillarin, NOP5/Nop58p, Diskerin/Cbf5p, SUS2/PRP8 and CLO/GFA1/sn114p) and 40S ribosomal associated proteins (22 RPS and four ARCA-like proteins). Another major protein group is composed of chaperones/chaperonins (HSP81/TCP-1) and at least one proteasome subunit (RPN1a). Remarkably, RNA-dependent RNA polymerase (RdRP) and Tudor staphylococcal nuclease (TSN) proteins, which have RNA- and/or DNA-associated activities, were also revealed in the complex. Furthermore, three U3 snoRNA variants were identified in the BoU3 snoRNP fraction, notably an evolutionarily conserved and variable stem loop structure located just downstream from the C-box domain of the U3 sequence structures. We conclude that the BoU3 snoRNP complex is mainly required for 40S pre-ribosome synthesis. It is also expected that U3 snoRNA variants and interacting proteins might play a major role in BoU3 snoRNP complex assembly and/or function. This study provides a basis for further investigation of these novel ribonucleoprotein factors and their role in plant ribosome biogenesis.


Assuntos
Brassica/genética , Brassica/metabolismo , Proteínas de Plantas/metabolismo , Precursores de RNA/metabolismo , RNA Nucleolar Pequeno/metabolismo , Ribonucleoproteínas/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Brassica/química , Sequência Conservada , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Proteínas de Plantas/química , RNA Nucleolar Pequeno/química , RNA Nucleolar Pequeno/isolamento & purificação , Ribonucleoproteínas/química , Alinhamento de Sequência
10.
Plant Physiol ; 150(3): 1494-502, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19411372

RESUMO

Functional transfer RNA (tRNA) molecules are a prerequisite for protein biosynthesis. Several processing steps are required to generate the mature functional tRNA from precursor molecules. Two of the early processing steps involve cleavage at the tRNA 5' end and the tRNA 3' end. While processing at the tRNA 5' end is performed by RNase P, cleavage at the 3' end is catalyzed by the endonuclease tRNase Z. In eukaryotes, tRNase Z enzymes are found in two versions: a short form of about 250 to 300 amino acids and a long form of about 700 to 900 amino acids. All eukaryotic genomes analyzed to date encode at least one long tRNase Z protein. Of those, Arabidopsis (Arabidopsis thaliana) is the only organism that encodes four tRNase Z proteins, two short forms and two long forms. We show here that the four proteins are distributed to different subcellular compartments in the plant cell: the nucleus, the cytoplasm, the mitochondrion, and the chloroplast. One tRNase Z is present only in the cytoplasm, one protein is found exclusively in mitochondria, while the third one has dual locations: nucleus and mitochondria. None of these three tRNase Z proteins is essential. The fourth tRNase Z protein is present in chloroplasts, and deletion of its gene results in an embryo-lethal phenotype. In vitro analysis with the recombinant proteins showed that all four tRNase Z enzymes have tRNA 3' processing activity. In addition, the mitochondrial tRNase Z proteins cleave tRNA-like elements that serve as processing signals in mitochondrial mRNA maturation.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/enzimologia , Endorribonucleases/genética , Arabidopsis/embriologia , Arabidopsis/genética , Proteínas de Arabidopsis/análise , Proteínas de Arabidopsis/química , Núcleo Celular/enzimologia , Cloroplastos/enzimologia , Citoplasma/enzimologia , Endorribonucleases/análise , Endorribonucleases/química , Mitocôndrias/enzimologia , Mutação , Conformação de Ácido Nucleico , Fenótipo , Sementes/enzimologia , Sementes/genética , Sementes/crescimento & desenvolvimento
11.
Plant Physiol ; 150(3): 1598-610, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19420328

RESUMO

The C/D box small nucleolar RNAs (snoRNAs) represent an essential class of small nucleolar RNAs that guide 2'-O-Rib methylation of ribosomal RNAs and other RNAs in eukaryotes. In Arabidopsis (Arabidopsis thaliana), >100 C/D snoRNAs have been identified, most of them encoded by polycistronic gene clusters, but little is known on the factors controlling their biogenesis. Here, we focus on the identification of factors controlling the processing of tRNA-snoRNA dicistronic precursors (pre-tsnoRNA) synthesized by RNA polymerase III and producing tRNA(Gly) and C/D snoR43. We produced radiolabeled RNA probes corresponding to different pre-tsnoRNA mutants to test their impact on processing in vitro by a recombinant tRNAse Z, the Arabidopsis endonuclease that processes the 3'end of tRNAs, and by nuclear extracts from cauliflower (Brassica oleracea) inflorescences that accurately process the pre-tsnoRNA. This was coupled to an in vivo analysis of the processing of tagged pre-tsnoRNA mutants expressed in Arabidopsis. Our results strongly implicate tRNase Z in endonucleolytic cleavage of the pre-tsnoRNA. In addition, they reveal an alternate pathway that could depend on a tRNA decay surveillance mechanism. Finally, we provide arguments showing that processing of pre-tsnoRNA, both in planta and by nuclear extracts, is coupled to the assembly of snoRNA with core proteins forming the functional snoRNP (for small nucleolar ribonucleoprotein complex).


Assuntos
Arabidopsis/genética , Precursores de RNA/metabolismo , RNA Nucleolar Pequeno/metabolismo , Aminoacil-RNA de Transferência/metabolismo , Arabidopsis/metabolismo , Sequência de Bases , Modelos Genéticos , Dados de Sequência Molecular , Mutação , Conformação de Ácido Nucleico , RNA Polimerase III/metabolismo , Precursores de RNA/genética , RNA Nucleolar Pequeno/química , RNA Nucleolar Pequeno/genética , Proteínas Recombinantes/metabolismo
12.
BMC Plant Biol ; 8: 123, 2008 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-19055717

RESUMO

BACKGROUND: The plant miRNAs represent an important class of endogenous small RNAs that guide cleavage of an mRNA target or repress its translation to control development and adaptation to stresses. MiRNAs are nuclear-encoded genes transcribed by RNA polymerase II, producing a primary precursor that is subsequently processed by DCL1 an RNase III Dicer-like protein. In rice hundreds of miRNAs have been described or predicted, but little is known on their genes and precursors which are important criteria to distinguish them from siRNAs. Here we develop a combination of experimental approaches to detect novel miRNAs in rice, identify their precursor transcripts and genes and predict or validate their mRNA targets. RESULTS: We produced four cDNA libraries from small RNA fractions extracted from distinct rice tissues. By in silico analysis we selected 6 potential novel miRNAs, and confirmed that their expression requires OsDCL1. We predicted their targets and used 5'RACE to validate cleavage for three of them, targeting a PPR, an SPX domain protein and a GT-like transcription factor respectively. In addition, we identified precursor transcripts for the 6 miRNAs expressed in rice, showing that these precursors can be efficiently processed using a transient expression assay in transfected Nicotiana benthamiana leaves. Most interestingly, we describe two precursors producing tandem miRNAs, but in distinct arrays. We focus on one of them encoding osa-miR159a.2, a novel miRNA produced from the same stem-loop structure encoding the conserved osa-miR159a.1. We show that this dual osa-miR159a.2-osa-miR159a.1 structure is conserved in distant rice species and maize. Finally we show that the predicted mRNA target of osa-miR159a.2 encoding a GT-like transcription factor is cleaved in vivo at the expected site. CONCLUSION: The combination of approaches developed here identified six novel miRNAs expressed in rice which can be clearly distinguished from siRNAs. Importantly, we show that two miRNAs can be produced from a single precursor, either from tandem stem-loops or tandemly arrayed in a single stem-loop. This suggests that processing of these precursors could be an important regulatory step to produce one or more functional miRNAs in plants and perhaps coordinate cleavage of distinct targets in the same plant tissue.


Assuntos
Regulação da Expressão Gênica de Plantas , Variação Genética , Genoma de Planta/genética , MicroRNAs/genética , Oryza/genética , Precursores de RNA/genética , Sequência de Bases , Sequência Conservada , Perfilação da Expressão Gênica , Genes de Plantas , Dados de Sequência Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Homologia de Sequência do Ácido Nucleico
13.
Trends Plant Sci ; 13(7): 335-42, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18555733

RESUMO

The gene organization of small nucleolar RNAs (snoRNAs) and microRNAs (miRNAs) varies within and among different organisms. This diversity is reflected in the maturation pathways of these small noncoding RNAs (ncRNAs). The presence of noncoding RNAs in introns has implications for the biogenesis of both mature small RNAs and host mRNA. The balance of the interactions between the processing or ribonucleoprotein assembly of intronic noncoding RNAs and the splicing process can regulate the levels of ncRNA and host mRNA. The processing of snoRNAs - both intronic and non-intronic - is well characterised in yeast, plants and animals and provides a basis for examining how intronic plant miRNAs are processed.


Assuntos
Íntrons/genética , Splicing de RNA , RNA de Plantas/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Modelos Biológicos , RNA de Plantas/metabolismo
14.
Dermatol Online J ; 13(2): 19, 2007 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-17498438

RESUMO

Angiokeratoma is a benign vascular lesion characterized by vascular ectasia in the upper dermis and hyperkeratosis. We report a case with lesions on the glans penis, a very rare location. In addition, we report the dermoscopic findings.


Assuntos
Angioceratoma/patologia , Pênis/patologia , Neoplasias Cutâneas/patologia , Idoso , Angioceratoma/diagnóstico , Biópsia por Agulha , Seguimentos , Humanos , Imuno-Histoquímica , Masculino , Neoplasias Cutâneas/diagnóstico
15.
Plant J ; 49(6): 1053-63, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17286797

RESUMO

Animal and yeast nucleolin function as global regulators of ribosome synthesis, and their expression is tightly linked to cell proliferation. Although Arabidopsis contains two genes for nucleolin, AtNuc-L1 is the predominant if not only form of the protein found in most tissues, and GFP-AtNuc-L1 fusion proteins were targeted to the nucleolus. Expression of AtNuc-L1 was strongly induced by sucrose or glucose but not by non-metabolizable mannitol or 2-deoxyglucose. Sucrose also caused enhanced expression of genes for subunits of C/D and H/ACA small nucleolar ribonucleoproteins, as well as a large number of genes for ribosomal proteins (RPs), suggesting that carbohydrate availability regulates de novo ribosome synthesis. In sugar-starved cells, induction of AtNuc-L1 occurred with 10 mM glucose, which seemed to be a prerequisite for resumption of growth. Disruption of AtNuc-L1 caused an increased steady-state level of pre-rRNA relative to mature 25S rRNA, and resulted in various phenotypes that overlap those reported for several RP gene mutants, including a reduced growth rate, prolonged lifetime, bushy growth, pointed leaf, and defective vascular patterns and pod development. These results suggest that the rate of ribosome synthesis in the meristem has a strong impact not only on the growth but also the structure of plants. The AtNuc-L1 disruptant exhibited significantly reduced sugar-induced expression of RP genes, suggesting that AtNuc-L1 is involved in the sugar-inducible expression of RP genes.


Assuntos
Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Fosfoproteínas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Ribossomos/metabolismo , Sacarose , Arabidopsis/fisiologia , Fosfoproteínas/genética , Proteínas de Ligação a RNA/genética , Nucleolina
16.
Mol Biol Cell ; 18(2): 369-79, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17108323

RESUMO

Nucleolin is one of the most abundant protein in the nucleolus and is a multifunctional protein involved in different steps of ribosome biogenesis. In contrast to animals and yeast, the genome of the model plant Arabidopsis thaliana encodes two nucleolin-like proteins, AtNUC-L1 and AtNUC-L2. However, only the AtNUC-L1 gene is ubiquitously expressed in normal growth conditions. Disruption of this AtNUC-L1 gene leads to severe plant growth and development defects. AtNUC-L1 is localized in the nucleolus, mainly in the dense fibrillar component. Absence of this protein in Atnuc-L1 plants induces nucleolar disorganization, nucleolus organizer region decondensation, and affects the accumulation levels of pre-rRNA precursors. Remarkably, in Atnuc-L1 plants the AtNUC-L2 gene is activated, suggesting that AtNUC-L2 might rescue, at least partially, the loss of AtNUC-L1. This work is the first description of a higher eukaryotic organism with a disrupted nucleolin-like gene and defines a new role for nucleolin in nucleolus structure and rDNA chromatin organization.


Assuntos
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/fisiologia , Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Fosfoproteínas/fisiologia , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/fisiologia , Sequência de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/análise , Nucléolo Celular/química , Nucléolo Celular/metabolismo , Nucléolo Celular/ultraestrutura , Núcleo Celular/química , DNA Ribossômico/metabolismo , Genoma de Planta/genética , Heterocromatina/química , Heterocromatina/metabolismo , Dados de Sequência Molecular , Proteínas Nucleares/análise , Proteínas Nucleares/genética , Fosfoproteínas/genética , RNA Ribossômico/biossíntese , Proteínas de Ligação a RNA/análise , Nucleolina
17.
Plant Cell Physiol ; 47(9): 1295-308, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16926165

RESUMO

Casein kinase 2 (CK2) is a ubiquitous enzyme essential for the viability of eukaryotic cells. In the present work we analyzed the Arabidopsis thaliana genome in a search for the genes coding for all CK2 alpha and beta subunits. We found four alpha subunit and four beta subunit genes. Expression analysis showed that all CK2 subunit genes are expressed in inflorescences, stems, leaves and roots. The level of expression of these genes is very similar, except for the one that codes for an alpha subunit harboring a putative chloroplastic destination peptide (alphacp), which shows a slightly higher expression level in all tissues. Using transgenic plants and agroinfiltration, we have also characterized the subcellular localization of all proteins encoded by CK2 genes. Our results show that all alpha subunits are localized in the nucleus, with the exception of alphacp, which is only found in the chloroplasts. On the other hand, beta subunits have a more diverse distribution, with some of them localizing both to the nucleus and to the cytosol, while others are exclusively located in one of these compartments. Remarkably, no CK2beta subunit was found in the chloroplasts. Finally, by directly measuring its activity, we have demonstrated that purified Arabidopsis chloroplasts have active CK2 that can be regulated by external addition of CK2beta. This study represents a complete survey of the CK2 gene family in Arabidopsis and the first step for future studies on CK2 cellular function in this species.


Assuntos
Arabidopsis/enzimologia , Caseína Quinase II/metabolismo , Sequência de Aminoácidos , Arabidopsis/classificação , Arabidopsis/genética , Caseína Quinase II/química , Caseína Quinase II/genética , Cloroplastos/enzimologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Genoma de Planta , Isoenzimas/análise , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência
18.
Rev. psicoanál. (Madr.) ; (45): 91-101, mayo-ago. 2005.
Artigo em Espanhol | IBECS | ID: ibc-125591

RESUMO

El análisis de un hombre joven es el punto de partida para estudiar la noción de vergüenza primaria enraizándola en sus fundamentos edípicos, explorando algunas de sus relaciones con el masoquismo, la analidad y la hostilidad teniendo como hilo conductor la homosexualidad primaria y lo femenino en el chico (AU)


The analysis of a Young man is the starting point for a study of the notion of primary shame, which takes root in its oedipical foundations, exploring some of his relations with masochism, anality and hostility, the main thread being primary homosexuality and the feminine in the young man (AU)


Assuntos
Humanos , Masculino , Adolescente , Adulto Jovem , Vergonha , Masoquismo/psicologia , Hostilidade , Homossexualidade/psicologia , Emoções , Masoquismo/epidemiologia , Masoquismo/prevenção & controle , Masoquismo/fisiopatologia
20.
Nucleic Acids Res ; 33(Database issue): D641-6, 2005 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-15608279

RESUMO

Genomic projects heavily depend on genome annotations and are limited by the current deficiencies in the published predictions of gene structure and function. It follows that, improved annotation will allow better data mining of genomes, and more secure planning and design of experiments. The purpose of the GeneFarm project is to obtain homogeneous, reliable, documented and traceable annotations for Arabidopsis nuclear genes and gene products, and to enter them into an added-value database. This re-annotation project is being performed exhaustively on every member of each gene family. Performing a family-wide annotation makes the task easier and more efficient than a gene-by-gene approach since many features obtained for one gene can be extrapolated to some or all the other genes of a family. A complete annotation procedure based on the most efficient prediction tools available is being used by 16 partner laboratories, each contributing annotated families from its field of expertise. A database, named GeneFarm, and an associated user-friendly interface to query the annotations have been developed. More than 3000 genes distributed over 300 families have been annotated and are available at http://genoplante-info.infobiogen.fr/Genefarm/. Furthermore, collaboration with the Swiss Institute of Bioinformatics is underway to integrate the GeneFarm data into the protein knowledgebase Swiss-Prot.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Bases de Dados Genéticas , Genes de Plantas , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/fisiologia , Filosofia , Integração de Sistemas , Interface Usuário-Computador
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