Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Epigenomes ; 8(1)2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38534792

RESUMO

While reports on the generational inheritance of a parental response to stress have been widely reported in animals, the molecular mechanisms behind this phenomenon have only recently emerged. The booming interest in epigenetic inheritance has been facilitated in part by the discovery that small non-coding RNAs are one of its principal conduits. Discovered 30 years ago in the Caenorhabditis elegans nematode, these small molecules have since cemented their critical roles in regulating virtually all aspects of eukaryotic development. Here, we provide an overview on the current understanding of epigenetic inheritance in animals, including mice and C. elegans, as it pertains to stresses such as temperature, nutritional, and pathogenic encounters. We focus on C. elegans to address the mechanistic complexity of how small RNAs target their cohort mRNAs to effect gene expression and how they govern the propagation or termination of generational perdurance in epigenetic inheritance. Presently, while a great amount has been learned regarding the heritability of gene expression states, many more questions remain unanswered and warrant further investigation.

2.
Elife ; 102021 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-34236316

RESUMO

In animals, early-life stress can result in programmed changes in gene expression that can affect their adult phenotype. In C. elegans nematodes, starvation during the first larval stage promotes entry into a stress-resistant dauer stage until environmental conditions improve. Adults that have experienced dauer (postdauers) retain a memory of early-life starvation that results in gene expression changes and reduced fecundity. Here, we show that the endocrine pathways attributed to the regulation of somatic aging in C. elegans adults lacking a functional germline also regulate the reproductive phenotypes of postdauer adults that experienced early-life starvation. We demonstrate that postdauer adults reallocate fat to benefit progeny at the expense of the parental somatic fat reservoir and exhibit increased longevity compared to controls. Our results also show that the modification of somatic fat stores due to parental starvation memory is inherited in the F1 generation and may be the result of crosstalk between somatic and reproductive tissues mediated by the germline nuclear RNAi pathway.


Assuntos
Envelhecimento/metabolismo , Caenorhabditis elegans/fisiologia , Reprodução/fisiologia , Envelhecimento/genética , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Ácidos Graxos/metabolismo , Fertilidade , Regulação da Expressão Gênica no Desenvolvimento , Células Germinativas , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Larva/fisiologia , Longevidade , Masculino , Fatores de Alongamento de Peptídeos/metabolismo , Fenótipo , Interferência de RNA , Reprodução/genética , Inanição
3.
Neurochem Int ; 148: 105086, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34082061

RESUMO

Since their discovery, small non-coding RNAs have emerged as powerhouses in the regulation of numerous cellular processes. In addition to guarding the integrity of the reproductive system, small non-coding RNAs play critical roles in the maintenance of the soma. Accumulating evidence indicates that small non-coding RNAs perform vital functions in the animal nervous system such as restricting the activity of deleterious transposable elements, regulating nerve regeneration, and mediating learning and memory. In this review, we provide an overview of the current understanding of the contribution of two major classes of small non-coding RNAs, piRNAs and endo-siRNAs, to the nervous system development and function, and present highlights on how the dysregulation of small non-coding RNA pathways can assist in understanding the neuropathology of human neurological disorders.


Assuntos
Fenômenos Fisiológicos do Sistema Nervoso/genética , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/fisiologia , Animais , Humanos , Doenças do Sistema Nervoso/genética , Doenças do Sistema Nervoso/fisiopatologia , Interferência de RNA
5.
PLoS Genet ; 14(2): e1007219, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29447162

RESUMO

Environmental stress during early development in animals can have profound effects on adult phenotypes via programmed changes in gene expression. Using the nematode C. elegans, we demonstrated previously that adults retain a cellular memory of their developmental experience that is manifested by differences in gene expression and life history traits; however, the sophistication of this system in response to different environmental stresses, and how it dictates phenotypic plasticity in adults that contribute to increased fitness in response to distinct environmental challenges, was unknown. Using transcriptional profiling, we show here that C. elegans adults indeed retain distinct cellular memories of different environmental conditions. We identified approximately 500 genes in adults that entered dauer due to starvation that exhibit significant opposite ("seesaw") transcriptional phenotypes compared to adults that entered dauer due to crowding, and are distinct from animals that bypassed dauer. Moreover, we show that two-thirds of the genes in the genome experience a 2-fold or greater seesaw trend in gene expression, and based upon the direction of change, are enriched in large, tightly linked regions on different chromosomes. Importantly, these transcriptional programs correspond to significant changes in brood size depending on the experienced stress. In addition, we demonstrate that while the observed seesaw gene expression changes occur in both somatic and germline tissue, only starvation-induced changes require a functional GLP-4 protein necessary for germline development, and both programs require the Argonaute CSR-1. Thus, our results suggest that signaling between the soma and the germ line can generate phenotypic plasticity as a result of early environmental experience, and likely contribute to increased fitness in adverse conditions and the evolution of the C. elegans genome.


Assuntos
Caenorhabditis elegans , Meio Ambiente , Reprodução/genética , Estresse Fisiológico/fisiologia , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/genética , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/fisiologia , Cromossomos/metabolismo , Cromossomos/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Interação Gene-Ambiente , Células Germinativas/fisiologia , Proteínas de Membrana/fisiologia , Fenótipo , Transdução de Sinais/genética
6.
Curr Biol ; 27(20): 3168-3177.e3, 2017 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-28988862

RESUMO

Experiences during early development can influence neuronal functions and modulate adult behaviors [1, 2]. However, the molecular mechanisms underlying the long-term behavioral effects of these early experiences are not fully understood. The C. elegans ascr#3 (asc-ΔC9; C9) pheromone triggers avoidance behavior in adult hermaphrodites [3-7]. Here, we show that hermaphrodites that are briefly exposed to ascr#3 immediately after birth exhibit increased ascr#3-specific avoidance as adults, indicating that ascr#3-experienced animals form a long-lasting memory or imprint of this early ascr#3 exposure [8]. ascr#3 imprinting is mediated by increased synaptic activity between the ascr#3-sensing ADL neurons and their post-synaptic SMB motor neuron partners via increased expression of the odr-2 glycosylated phosphatidylinositol (GPI)-linked signaling gene in the SMB neurons. Our study suggests that the memory for early ascr#3 experience is imprinted via alteration of activity of a single synaptic connection, which in turn shapes experience-dependent plasticity in adult ascr#3 responses.


Assuntos
Caenorhabditis elegans/fisiologia , Memória , Feromônios/fisiologia , Células Receptoras Sensoriais/fisiologia , Animais , Aprendizagem da Esquiva , Organismos Hermafroditas/fisiologia , Transdução de Sinais
7.
Development ; 144(16): 2896-2906, 2017 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-28811311

RESUMO

The developmental accumulation of proliferative germ cells in the C. elegans hermaphrodite is sensitive to the organismal environment. Previously, we found that the TGFß signaling pathway links the environment and proliferative germ cell accumulation. Neuronal DAF-7/TGFß causes a DAF-1/TGFßR signaling cascade in the gonadal distal tip cell (DTC), the germline stem cell niche, where it negatively regulates a DAF-3 SMAD and DAF-5 Sno-Ski. LAG-2, a founding DSL ligand family member, is produced in the DTC and activates the GLP-1/Notch receptor on adjacent germ cells to maintain germline stem cell fate. Here, we show that DAF-7/TGFß signaling promotes expression of lag-2 in the DTC in a daf-3-dependent manner. Using ChIP and one-hybrid assays, we find evidence for direct interaction between DAF-3 and the lag-2 promoter. We further identify a 25 bp DAF-3 binding element required for the DTC lag-2 reporter response to the environment and to DAF-7/TGFß signaling. Our results implicate DAF-3 repressor complex activity as a key molecular mechanism whereby the environment influences DSL ligand expression in the niche to modulate developmental expansion of the germline stem cell pool.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Nicho de Células-Tronco/fisiologia , Fator de Crescimento Transformador beta/metabolismo , Animais , Caenorhabditis elegans/citologia , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Imunoprecipitação da Cromatina , Hibridização In Situ , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Nicho de Células-Tronco/genética , Fator de Crescimento Transformador beta/genética
8.
Elife ; 52016 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-27351255

RESUMO

Environmental stress during early development can impact adult phenotypes via programmed changes in gene expression. C. elegans larvae respond to environmental stress by entering the stress-resistant dauer diapause pathway and resume development once conditions improve (postdauers). Here we show that the osm-9 TRPV channel gene is a target of developmental programming and is down-regulated specifically in the ADL chemosensory neurons of postdauer adults, resulting in a corresponding altered olfactory behavior that is mediated by ADL in an OSM-9-dependent manner. We identify a cis-acting motif bound by the DAF-3 SMAD and ZFP-1 (AF10) proteins that is necessary for the differential regulation of osm-9, and demonstrate that both chromatin remodeling and endo-siRNA pathways are major contributors to the transcriptional silencing of the osm-9 locus. This work describes an elegant mechanism by which developmental experience influences adult phenotypes by establishing and maintaining transcriptional changes via RNAi and chromatin remodeling pathways.


Assuntos
Comportamento Animal , Caenorhabditis elegans/embriologia , Regulação da Expressão Gênica no Desenvolvimento , Sistema Límbico/embriologia , Percepção Olfatória , Interferência de RNA , Olfato , Animais , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Canais de Cátion TRPV/metabolismo
9.
Methods Mol Biol ; 1327: 209-19, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26423977

RESUMO

The C. elegans dauer is an attractive model with which to investigate fundamental biological questions, such as how environmental cues are sensed and are translated into developmental decisions through a series of signaling cascades that ultimately result in a transformed animal. Here we describe a simple method of using egg white plates to obtain highly synchronized purified dauers that can be used in downstream applications requiring large quantities of dauers or postdauer animals.


Assuntos
Caenorhabditis elegans/fisiologia , Animais , Larva
10.
Methods Mol Biol ; 1173: 59-70, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24920360

RESUMO

In recent years, distinct classes of small RNAs ranging in size from ~21 to 26 nucleotides have been discovered and shown to play important roles in a wide array of cellular functions. Because of the abundance of these small RNAs, library preparation from an RNA sample followed by deep sequencing provides the identity and quantity of a particular class of small RNAs. In this chapter we describe a detailed protocol for preparing small RNA libraries for deep sequencing on the Illumina platform from the nematode C. elegans.


Assuntos
Caenorhabditis elegans/genética , Clonagem Molecular/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , RNA Interferente Pequeno/genética , Animais , Sequência de Bases , Biblioteca Gênica , RNA Interferente Pequeno/química , Transcrição Reversa
11.
Mol Cell ; 50(2): 281-7, 2013 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-23541767

RESUMO

In metazoans, microRNAs play a critical role in the posttranscriptional regulation of genes required for cell proliferation and differentiation. MicroRNAs themselves are regulated by a multitude of mechanisms influencing their transcription and posttranscriptional maturation. However, there is only sparse knowledge on pathways regulating the mature, functional form of microRNA. Here, we uncover the implication of the decapping scavenger protein DCS-1 in the control of microRNA turnover. In Caenorhabditis elegans, mutations in dcs-1 increase the levels of functional microRNAs. We demonstrate that DCS-1 interacts with the exonuclease XRN-1 to promote microRNA degradation in an independent manner from its known decapping scavenger activity, establishing two molecular functions for DCS-1. Our findings thus indicate that DCS-1 is part of a degradation complex that performs microRNA turnover in animals.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/enzimologia , MicroRNAs/metabolismo , N-Glicosil Hidrolases/metabolismo , RNA de Helmintos/metabolismo , Animais , Proteínas de Caenorhabditis elegans/genética , Exorribonucleases/metabolismo , Expressão Gênica , Mutação , N-Glicosil Hidrolases/genética , Pirofosfatases , Interferência de RNA , Estabilidade de RNA , Complexo de Inativação Induzido por RNA/metabolismo
12.
RNA ; 17(4): 639-51, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21343388

RESUMO

Animals have evolved mechanisms to ensure the robustness of developmental outcomes to changing environments. MicroRNA expression may contribute to developmental robustness because microRNAs are key post-transcriptional regulators of developmental gene expression and can affect the expression of multiple target genes. Caenorhabditis elegans provides an excellent model to study developmental responses to environmental conditions. In favorable environments, C. elegans larvae develop rapidly and continuously through four larval stages. In contrast, in unfavorable conditions, larval development may be interrupted at either of two diapause stages: The L1 diapause occurs when embryos hatch in the absence of food, and the dauer diapause occurs after the second larval stage in response to environmental stimuli encountered during the first two larval stages. Dauer larvae are stress resistant and long lived, permitting survival in harsh conditions. When environmental conditions improve, dauer larvae re-enter development, and progress through two post-dauer larval stages to adulthood. Strikingly, all of these life history options (whether continuous or interrupted) involve an identical pattern and sequence of cell division and cell fates. To identify microRNAs with potential functions in buffering development in the context of C. elegans life history options, we used multiplex real-time PCR to assess the expression of 107 microRNAs throughout development in both continuous and interrupted life histories. We identified 17 microRNAs whose developmental profile of expression is affected by dauer life history and/or L1 diapause, compared to continuous development. Hence these microRNAs could function to regulate gene expression programs appropriate for different life history options in the developing worm.


Assuntos
Caenorhabditis elegans/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , MicroRNAs/genética , Animais , Caenorhabditis elegans/genética , Transcrição Gênica , Regulação para Cima
13.
Genome Res ; 18(12): 2005-15, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18981266

RESUMO

The Caenorhabditis elegans genome encodes more than 100 microRNAs (miRNAs). Genetic analyses of miRNA deletion mutants have only provided limited insights into miRNA function. To gain insight into the function of miRNAs, it is important to determine their spatiotemporal expression pattern. Here, we use miRNA promoters driving the expression of GFP as a proxy for miRNA expression. We describe a set of 73 transgenic C. elegans strains, each expressing GFP under the control of a miRNA promoter. Together, these promoters control the expression of 89 miRNAs (66% of all predicted miRNAs). We find that miRNA promoters drive GFP expression in a variety of tissues and that, overall, their activity is similar to that of protein-coding gene promoters. However, miRNAs are expressed later in development, which is consistent with functions after initial body-plan specification. We find that miRNA members belonging to families are more likely to be expressed in overlapping tissues than miRNAs that do not belong to the same family, and provide evidence that intronic miRNAs may be controlled by their own, rather than a host gene promoter. Finally, our data suggest that post-transcriptional mechanisms contribute to differential miRNA expression. The data and strains described here will provide a valuable guide and resource for the functional analysis of C. elegans miRNAs.


Assuntos
Caenorhabditis elegans/genética , Genes de Helmintos , Genoma Helmíntico , MicroRNAs , Regiões Promotoras Genéticas , Animais , Animais Geneticamente Modificados , Northern Blotting , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/metabolismo , Embrião não Mamífero , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Fluorescência Verde/metabolismo , Processamento de Proteína Pós-Traducional , RNA de Helmintos/genética , Fatores de Tempo
14.
Genes Dev ; 22(18): 2520-34, 2008 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-18794349

RESUMO

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression post-transcriptionally via antisense base-pairing. Although miRNAs are involved in a variety of important biological functions, little is known about their transcriptional regulation. Using yeast one-hybrid assays, we identified transcription factors with a FLYWCH Zn-finger DNA-binding domain that bind to the promoters of several Caenorhabditis elegans miRNA genes. The products of the flh-1 and flh-2 genes function redundantly to repress embryonic expression of lin-4, mir-48, and mir-241, miRNA genes that are normally expressed only post-embryonically. Although single mutations in either flh-1 or flh-2 genes result in a viable phenotype, double mutation of flh-1 and flh-2 results in early larval lethality and an enhanced derepression of their target miRNAs in embryos. Double mutations in flh-2 and a third FLYWCH Zn-finger-containing transcription factor, flh-3, also result in enhanced precocious expression of target miRNAs. Mutations of lin-4 or mir-48&mir-241 do not rescue the lethal flh-1; flh-2 double-mutant phenotype, suggesting that the inviability is not solely the result of precocious expression of these miRNAs. Therefore, the FLH-1 and FLH-2 proteins likely play a more general role in regulating gene expression in embryos.


Assuntos
Caenorhabditis elegans/genética , Regulação da Expressão Gênica no Desenvolvimento , Genes de Helmintos , MicroRNAs/genética , Fatores de Transcrição/fisiologia , Sequência de Aminoácidos , Animais , Sítios de Ligação , Caenorhabditis elegans/embriologia , Dados de Sequência Molecular , Interferência de RNA , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
15.
Genes Dev ; 22(18): 2535-49, 2008 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-18794350

RESUMO

MicroRNAs (miRNAs) and transcription factors (TFs) are primary metazoan gene regulators. Whereas much attention has focused on finding the targets of both miRNAs and TFs, the transcriptional networks that regulate miRNA expression remain largely unexplored. Here, we present the first genome-scale Caenorhabditis elegans miRNA regulatory network that contains experimentally mapped transcriptional TF --> miRNA interactions, as well as computationally predicted post-transcriptional miRNA --> TF interactions. We find that this integrated miRNA network contains 23 miRNA <--> TF composite feedback loops in which a TF that controls a miRNA is itself regulated by that same miRNA. By rigorous network randomizations, we show that such loops occur more frequently than expected by chance and, hence, constitute a genuine network motif. Interestingly, miRNAs and TFs in such loops are heavily regulated and regulate many targets. This "high flux capacity" suggests that loops provide a mechanism of high information flow for the coordinate and adaptable control of miRNA and TF target regulons.


Assuntos
Caenorhabditis elegans/genética , Genoma , MicroRNAs/genética , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/embriologia , Reação em Cadeia da Polimerase , Transcrição Gênica
16.
Mol Microbiol ; 49(3): 607-22, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12864847

RESUMO

RNase G (rng) is an E. coli endoribonuclease that is homologous to the catalytic domain of RNase E (rne), an essential protein that is a major participant in tRNA maturation, mRNA decay, rRNA processing and M1 RNA processing. We demonstrate here that whereas RNase G inefficiently participates in the degradation of mRNAs and the processing of 9S rRNA, it is not involved in either tRNA or M1 RNA processing. This conclusion is supported by the fact that inactivation of RNase G alone does not affect 9S rRNA processing and only leads to minor changes in mRNA half-lives. However, in rng rne double mutants mRNA decay and 9S rRNA processing are more defective than in either single mutant. Conversely, increasing RNase G levels in an rne-1 rng::cat double mutant, proportionally increased the extent of 9S rRNA processing and decreased the half-lives of specific mRNAs. In contrast, variations in the amount of RNase G did not alter tRNA processing under any circumstances. Thus, the failure of RNase G to complement rne mutations, even when overproduced at high levels, apparently results from its inability to substitute for RNase E in the maturation of tRNAs.


Assuntos
Endorribonucleases/fisiologia , Proteínas de Escherichia coli/fisiologia , Escherichia coli/enzimologia , RNA Bacteriano/metabolismo , Alelos , Domínio Catalítico , Endorribonucleases/química , Endorribonucleases/genética , Endorribonucleases/metabolismo , Escherichia coli/genética , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Teste de Complementação Genética , Meia-Vida , Subunidades Proteicas , Processamento Pós-Transcricional do RNA , RNA Catalítico/genética , RNA Catalítico/metabolismo , RNA Mensageiro/metabolismo , RNA Ribossômico/metabolismo , RNA de Transferência/metabolismo , Proteínas Recombinantes de Fusão/fisiologia , Ribonuclease P , Homologia de Sequência de Aminoácidos
17.
Genes Dev ; 16(9): 1102-15, 2002 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-12000793

RESUMO

RNase E, an essential endoribonuclease in Escherichia coli, is involved in 9S rRNA processing, the degradation of many mRNAs, and the processing of the M1 RNA subunit of RNase P. However, the reason that RNase E is required for cell viability is still not fully understood. In fact, recent experiments have suggested that defects in 9S rRNA processing and mRNA decay are not responsible for the lack of cell growth in RNase E mutants. By using several new rne alleles, we have confirmed these observations and have also ruled out that M1 processing by RNase E is required for cell viability. Rather, our data suggest that the critical in vivo role of RNase E is the initiation of tRNA maturation. Specifically, RNase E catalytic activity starts the processing of both polycistronic operons, such as glyW cysT leuZ, argX hisR leuT proM, and lysT valT lysW valZ lysY lysZ lysQ, as well as monocistronic transcripts like pheU, pheV, asnT, asnU, asnV, and asnW. Cleavage by RNase E within a few nucleotides of the mature 3' CCA terminus is required before RNase P and the various 3' --> 5' exonucleases can complete tRNA maturation. All 59 tRNAs tested involved RNase E processing, although some were cleaved more efficiently than others.


Assuntos
Endorribonucleases/metabolismo , Proteínas de Escherichia coli , Escherichia coli/genética , RNA de Transferência/metabolismo , Divisão Celular/genética , Endorribonucleases/genética , Escherichia coli/citologia , Mutação , Óperon , Precursores de RNA/metabolismo , Processamento Pós-Transcricional do RNA , RNA Catalítico/genética , RNA Catalítico/metabolismo , RNA de Transferência/genética , Mapeamento por Restrição , Ribonuclease P , Temperatura
18.
Mol Microbiol ; 43(1): 159-71, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11849544

RESUMO

The rne gene of Escherichia coli encodes RNase E, an essential endoribonuclease that is involved in both mRNA decay and rRNA processing. Here we present evidence that the gene is transcribed from three promoters: p1, p2 and p3. The p2 and p3 promoters map 34 and 145 nt upstream from the previously characterized rne promoter, p1, generating unusually long 5' UTRs of 395 and 506 nt respectively. Based on promoter-lacZ transcriptional fusions, p1 is a more efficient promoter than either p2 or p3. Low copy number or single copy number vectors carrying rne transcribed from either p1, p2 or p3 alone complement the rne 1018::bla deletion mutation at 30 degrees C, 37 degrees C and 44 degrees C. However, normal autoregulation requires the presence of all three promoters. A comparison among intracellular levels of RNase E, the half-lives of the rpsO, rpsT and rne mRNAs, and growth rates, indicates that the cell contains a considerable excess of RNase E protein. In addition, when the rne transcript is stabilized at low RNase E levels, it is not efficiently translated.


Assuntos
Endorribonucleases/genética , Escherichia coli/enzimologia , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Regiões Promotoras Genéticas , Regiões 5' não Traduzidas , Fusão Gênica Artificial , Sequência de Bases , DNA Bacteriano , Endorribonucleases/metabolismo , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Genes Bacterianos , Óperon Lac , Dados de Sequência Molecular , Mutagênese , RNA Bacteriano , RNA Mensageiro , Transcrição Gênica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...