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1.
MicroPubl Biol ; 20202020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33274317
2.
Development ; 147(20)2020 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-32994172

RESUMO

Brain development requires precise regulation of axon outgrowth, guidance and termination by multiple signaling and adhesion molecules. How the expression of these neurodevelopmental regulators is transcriptionally controlled is poorly understood. The Caenorhabditis elegans SMD motor neurons terminate axon outgrowth upon sexual maturity and partially retract their axons during early adulthood. Here we show that C-terminal binding protein 1 (CTBP-1), a transcriptional corepressor, is required for correct SMD axonal development. Loss of CTBP-1 causes multiple defects in SMD axon development: premature outgrowth, defective guidance, delayed termination and absence of retraction. CTBP-1 controls SMD axon guidance by repressing the expression of SAX-7, an L1 cell adhesion molecule (L1CAM). CTBP-1-regulated repression is crucial because deregulated SAX-7/L1CAM causes severely aberrant SMD axons. We found that axonal defects caused by deregulated SAX-7/L1CAM are dependent on a distinct L1CAM, called LAD-2, which itself plays a parallel role in SMD axon guidance. Our results reveal that harmonization of L1CAM expression controls the development and maturation of a single neuron.


Assuntos
Axônios/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Neurônios Motores/metabolismo , Moléculas de Adesão de Célula Nervosa/metabolismo , Crescimento Neuronal , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Regulação da Expressão Gênica no Desenvolvimento , Molécula L1 de Adesão de Célula Nervosa/genética , Molécula L1 de Adesão de Célula Nervosa/metabolismo , Crescimento Neuronal/genética , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo
3.
Sci Rep ; 7(1): 4579, 2017 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-28676648

RESUMO

LIM-Homeodomain (LIM-HD) transcription factors are highly conserved in animals where they are thought to act in a transcriptional 'LIM code' that specifies cell types, particularly in the central nervous system. In chick and mammals the interaction between two LIM-HD proteins, LHX3 and Islet1 (ISL1), is essential for the development of motor neurons. Using yeast two-hybrid analysis we showed that the Caenorhabditis elegans orthologs of LHX3 and ISL1, CEH-14 and LIM-7 can physically interact. Structural characterisation of a complex comprising the LIM domains from CEH-14 and a LIM-interaction domain from LIM-7 showed that these nematode proteins assemble to form a structure that closely resembles that of their vertebrate counterparts. However, mutagenic analysis across the interface indicates some differences in the mechanisms of binding. We also demonstrate, using fluorescent reporter constructs, that the two C. elegans proteins are co-expressed in a small subset of neurons. These data show that the propensity for LHX3 and Islet proteins to interact is conserved from C. elegans to mammals, raising the possibility that orthologous cell specific LIM-HD-containing transcription factor complexes play similar roles in the development of neuronal cells across diverse species.


Assuntos
Caenorhabditis elegans/metabolismo , Proteínas com Homeodomínio LIM/metabolismo , Fatores de Transcrição/metabolismo , Processamento Alternativo , Animais , Sítios de Ligação , Caenorhabditis elegans/genética , Sequência Conservada , Evolução Molecular , Regulação da Expressão Gênica , Proteínas com Homeodomínio LIM/química , Proteínas com Homeodomínio LIM/genética , Modelos Moleculares , Família Multigênica , Complexos Multiproteicos , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Mapeamento de Interação de Proteínas , Soluções , Fatores de Transcrição/química , Fatores de Transcrição/genética
4.
Sci Rep ; 6: 19582, 2016 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-26791749

RESUMO

Proteins of the Homeodomain-Interacting Protein Kinase (HIPK) family regulate an array of processes in mammalian systems, such as the DNA damage response, cellular proliferation and apoptosis. The nematode Caenorhabditis elegans has a single HIPK homologue called HPK-1. Previous studies have implicated HPK-1 in longevity control and suggested that this protein may be regulated in a stress-dependent manner. Here we set out to expand these observations by investigating the role of HPK-1 in longevity and in the response to heat and oxidative stress. We find that levels of HPK-1 are regulated by heat stress, and that HPK-1 contributes to survival following heat or oxidative stress. Additionally, we show that HPK-1 is required for normal longevity, with loss of HPK-1 function leading to a faster decline of physiological processes that reflect premature ageing. Through microarray analysis, we have found that HPK-1-regulated genes include those encoding proteins that serve important functions in stress responses such as Phase I and Phase II detoxification enzymes. Consistent with a role in longevity assurance, HPK-1 also regulates the expression of age-regulated genes. Lastly, we show that HPK-1 functions in the same pathway as DAF-16 to regulate longevity and reveal a new role for HPK-1 in development.


Assuntos
Envelhecimento/genética , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Regulação da Expressão Gênica , Proteínas Serina-Treonina Quinases/metabolismo , Estresse Fisiológico/genética , Animais , Técnicas de Inativação de Genes , Resposta ao Choque Térmico/genética , Insulina/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Mucosa Intestinal/metabolismo , Longevidade/genética , Estresse Oxidativo/genética , Transdução de Sinais
5.
J Biol Chem ; 290(13): 8591-605, 2015 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-25659434

RESUMO

Krüppel-like factor 3 (KLF3/BKLF), a member of the Krüppel-like factor (KLF) family of transcription factors, is a widely expressed transcriptional repressor with diverse biological roles. Although there is considerable understanding of the molecular mechanisms that allow KLF3 to silence the activity of its target genes, less is known about the signal transduction pathways and post-translational modifications that modulate KLF3 activity in response to physiological stimuli. We observed that KLF3 is modified in a range of different tissues and found that the serine/threonine kinase homeodomain-interacting protein kinase 2 (HIPK2) can both bind and phosphorylate KLF3. Mass spectrometry identified serine 249 as the primary phosphorylation site. Mutation of this site reduces the ability of KLF3 to bind DNA and repress transcription. Furthermore, we also determined that HIPK2 can phosphorylate the KLF3 co-repressor C-terminal binding protein 2 (CtBP2) at serine 428. Finally, we found that phosphorylation of KLF3 and CtBP2 by HIPK2 strengthens the interaction between these two factors and increases transcriptional repression by KLF3. Taken together, our results indicate that HIPK2 potentiates the activity of KLF3.


Assuntos
Proteínas de Transporte/fisiologia , Proteínas de Ligação a DNA/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , Fosfoproteínas/metabolismo , Proteínas Serina-Treonina Quinases/fisiologia , Oxirredutases do Álcool , Sequência de Aminoácidos , Animais , Células COS , Chlorocebus aethiops , Proteínas Correpressoras , DNA/química , Ensaio de Desvio de Mobilidade Eletroforética , Fatores de Transcrição Kruppel-Like/química , Camundongos , Dados de Sequência Molecular , Células NIH 3T3 , Fosforilação , Ligação Proteica , Processamento de Proteína Pós-Traducional , Transcrição Gênica , Ativação Transcricional
6.
Aging Cell ; 14(1): 148-51, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25399685

RESUMO

Oxidative stress is a central pathomechanism in Alzheimer's disease (AD) and other diseases with tau pathology. The Nrf2 transcription factor induces detoxification enzymes and improves tau pathology and cognition. Its homologue in C. elegans is SKN-1. We previously showed that the worm tau homologue, PTL-1, regulates neuronal aging and lifespan. Here, we tested PTL-1's involvement in the stress response. ptl-1 mutant animals are hypersensitive to oxidative stress and are defective in stress-mediated nuclear accumulation of SKN-1. This defect can be rescued by PTL-1 re-expression under the control of the ptl-1 promoter. Given the close relationship between aging and stress tolerance, we tested lifespan and found that PTL-1 and SKN-1 regulate longevity via similar processes. Our data also suggest that PTL-1 functions via neurons to modulate SKN-1, clarifying the role of this protein in the stress response and longevity.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Mucosa Intestinal/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Neurônios/metabolismo , Estresse Oxidativo , Fatores de Transcrição/metabolismo , Animais , Proteínas de Transporte/metabolismo , Transdução de Sinais , Estresse Fisiológico
7.
Nat Protoc ; 9(9): 2237-55, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25167056

RESUMO

In this protocol we describe the incorporation of bio-orthogonal amino acids as a versatile method for visualizing and identifying de novo-synthesized proteins in the roundworm Caenorhabditis elegans. This protocol contains directions on implementing three complementary types of analysis: 'click chemistry' followed by western blotting, click chemistry followed by immunofluorescence, and isobaric tags for relative and absolute quantification (iTRAQ) quantitative mass spectrometry. The detailed instructions provided herein enable researchers to investigate the de novo proteome, an analysis that is complicated by the fact that protein molecules are chemically identical to each other, regardless of the timing of their synthesis. Our protocol circumvents this limitation by identifying de novo-synthesized proteins via the incorporation of the chemically modifiable azidohomoalanine instead of the natural amino acid methionine in the nascent protein, followed by facilitating the visualization of the resulting labeled proteins in situ. It will therefore be an ideal tool for studying de novo protein synthesis in physiological and pathological processes including learning and memory. The protocol requires 10 d for worm growth, liquid culture and synchronization; 1-2 d for bio-orthogonal labeling; and, with regard to analysis, 3-4 d for western blotting, 5-6 d for immunofluorescence or ~3 weeks for mass spectrometry.


Assuntos
Aminoácidos/metabolismo , Proteínas de Caenorhabditis elegans/análise , Técnicas de Química Analítica/métodos , Química Click/métodos , Coloração e Rotulagem/métodos , Alanina/análogos & derivados , Animais , Western Blotting , Proteínas de Caenorhabditis elegans/metabolismo , Imunofluorescência , Espectrometria de Massas
8.
Sci Rep ; 4: 5185, 2014 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-24898126

RESUMO

PTL-1 is the sole homolog of the MAP2/MAP4/tau family in Caenorhabditis elegans. Accumulation of tau is a pathological hallmark of neurodegenerative diseases such as Alzheimer's disease. Therefore, reducing tau levels has been suggested as a therapeutic strategy. We previously showed that PTL-1 maintains age-related structural integrity in neurons, implying that excessive reduction in the levels of a tau-like protein is detrimental. Here, we demonstrate that the regulation of neuronal ageing by PTL-1 occurs via a cell-autonomous mechanism. We re-expressed PTL-1 in a null mutant background using a pan-neuronal promoter to show that PTL-1 functions in neurons to maintain structural integrity. We next expressed PTL-1 only in touch neurons and showed rescue of the neuronal ageing phenotype of ptl-1 mutant animals in these neurons but not in another neuronal subset, the ventral nerve cord GABAergic neurons. Knockdown of PTL-1 in touch neurons also resulted in premature neuronal ageing in these neurons but not in GABAergic neurons. Additionally, expression of PTL-1 in touch neurons alone was unable to rescue the shortened lifespan observed in ptl-1 mutants, but pan-neuronal re-expression restored wild-type longevity, indicating that, at least for a specific group of mechanosensory neurons, premature neuronal ageing and organismal ageing can be decoupled.


Assuntos
Animais Geneticamente Modificados/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Longevidade/fisiologia , Proteínas Associadas aos Microtúbulos/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Animais , Animais Geneticamente Modificados/genética , Caenorhabditis elegans/citologia , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/antagonistas & inibidores , Proteínas de Caenorhabditis elegans/genética , Imunofluorescência , Processamento de Imagem Assistida por Computador , Proteínas Associadas aos Microtúbulos/antagonistas & inibidores , Proteínas Associadas aos Microtúbulos/genética , Interferência de RNA
9.
Dev Biol ; 392(2): 266-82, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24882710

RESUMO

Chromatin regulators contribute to the developmental control of gene expression. In the nematode Caenorhabditis elegans, the roles of chromatin regulation in development have been explored in several contexts, including vulval differentiation. The synthetic multivulva (synMuv) genes are regulators of vulval development in C. elegans and the proteins encoded by these genes include components of several histone modification and chromatin remodelling complexes. By inhibiting ectopic expression of the epidermal growth factor (LIN-3) in the nematode hypodermis, the synMuv genes prevent inappropriate vulval induction. In a forward genetic screen for modifiers of the expression of a hypodermal reporter gene, we identified a mutation that results in increased expression of the reporter. This mutation also suppresses ectopic vulval induction in synMuv mutants and we have consequently named the affected gene suppressor of synthetic multivulva-1 (sumv-1). We show that SUMV-1 is required in the hypodermis for the synMuv phenotype and that loss of sumv-1 function suppresses ectopic expression of lin-3 in synMuv mutant animals. In yeast two-hybrid assays SUMV-1 physically interacts with SUMV-2, and reduction of sumv-2 function also suppresses the synMuv phenotype. We identified similarities between SUMV-1 and SUMV-2 and mammalian proteins KAT8 NSL2 and KAT8 NSL3, respectively, which are components of the KAT8/MOF histone acetyltransferase complex. Reduction of function of mys-2, which encodes the enzymatic component of the KAT8/MOF complex, also suppresses the synMuv phenotype, and MYS-2 physically interacts with SUMV-2 in yeast two-hybrid assays. Together these observations suggest that SUMV-1 and SUMV-2 may function together with MYS-2 in a nematode KAT8/MOF-like complex to antagonise the activity of the synMuv genes.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/embriologia , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Vulva/embriologia , Animais , Sequência de Bases , Western Blotting , Proteínas de Caenorhabditis elegans/antagonistas & inibidores , Proteínas de Caenorhabditis elegans/metabolismo , Primers do DNA/genética , Proteínas de Ligação a DNA/metabolismo , Fator de Crescimento Epidérmico/antagonistas & inibidores , Feminino , Histona Acetiltransferases/metabolismo , Hibridização in Situ Fluorescente , Dados de Sequência Molecular , Polimorfismo de Nucleotídeo Único/genética , Interferência de RNA , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Técnicas do Sistema de Duplo-Híbrido
10.
Cell Mol Life Sci ; 71(17): 3339-61, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24458371

RESUMO

Protein misfolding and aggregation as a consequence of impaired protein homeostasis (proteostasis) not only characterizes numerous age-related diseases but also the aging process itself. Functionally related to the aging process are, among others, ribosomal proteins, suggesting an intimate link between proteostasis and aging. We determined by iTRAQ quantitative proteomic analysis in C. elegans how the proteome changes with age and in response to heat shock. Levels of ribosomal proteins and mitochondrial chaperones were decreased in aged animals, supporting the notion that proteostasis is altered during aging. Mitochondrial enzymes of the tricarboxylic acid cycle and the electron transport chain were also reduced, consistent with an age-associated energy impairment. Moreover, we observed an age-associated decline in the heat shock response. In order to determine how protein synthesis is altered in aging and in response to heat shock, we complemented our global analysis by determining the de novo proteome. For that, we established a novel method that enables both the visualization and identification of de novo synthesized proteins, by incorporating the non-canonical methionine analogue, azidohomoalanine (AHA), into the nascent polypeptides, followed by reacting the azide group of AHA by 'click chemistry' with an alkyne-labeled tag. Our analysis of AHA-tagged peptides demonstrated that the decreased abundance of, for example, ribosomal proteins in aged animals is not solely due to degradation but also reflects a relative decrease in their synthesis. Interestingly, although the net rate of protein synthesis is reduced in aged animals, our analyses indicate that the synthesis of certain proteins such as the vitellogenins increases with age.


Assuntos
Envelhecimento/fisiologia , Proteínas de Caenorhabditis elegans/biossíntese , Resposta ao Choque Térmico/fisiologia , Proteoma , Alanina/análogos & derivados , Alanina/metabolismo , Animais , Western Blotting , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/classificação , Proteínas de Caenorhabditis elegans/genética , Química Click , Previsões , Regulação da Expressão Gênica , Genes de Helmintos , Resposta ao Choque Térmico/genética , Temperatura Alta , Espectrometria de Massas , Microscopia de Fluorescência , Dobramento de Proteína , Deficiências na Proteostase/metabolismo
11.
Worm ; 3(4): e982967, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-26430553

RESUMO

Regulation of chromatin is a key process in the developmental control of gene expression. Many multi-subunit protein complexes have been found to regulate chromatin through the modification of histone residues. One such complex is the MOF histone acetyltransferase-containing NSL complex. While the composition of the human and Drosophila NSL complexes has been determined and the functions of these complexes investigated, the existence of an equivalent complex in nematodes such as Caenorhabditis elegans has not yet been explored. Here we summarise evidence, from our own work and that of others, that homologues of NSL complex components are found in C. elegans. We review data suggesting that nematode proteins SUMV-1 and SUMV-2 are homologous to NSL2 and NSL3, respectively, and that SUMV-1 and SUMV-2 may form a complex with MYS-2, the worm homolog of MOF. We propose that these interactions suggest the existence of a nematode NSL-like complex and discuss the roles of this putative NSL complex in worms as well as exploring the possibility of crosstalk between NSL and COMPASS complexes via components that are common to both. We present the groundwork from which a full characterization of a nematode NSL complex may begin.

12.
Commun Integr Biol ; 6(5): e25288, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-24255742

RESUMO

It has recently been described that aging in C. elegans is accompanied by the progressive development of morphological changes in the nervous system. These include novel outgrowths from the cell body or axonal process, as well as blebbing and beading along the length of the axon. The formation of these structures is regulated by numerous molecular players including members of the well-conserved insulin/insulin growth factor-like (IGF)-1 signaling and mitogen-activated protein (MAP) kinase pathways. This review summarizes the recent literature on neuronal aging in C. elegans, including our own findings, which indicate a role for protein with tau-like repeats (PTL-1), the homolog of mammalian tau and MAP2/4, in maintaining neuronal integrity during aging.

13.
Dev Dyn ; 242(11): 1250-61, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23904186

RESUMO

BACKGROUND: Tightly regulated pathways maintain the balance between proliferation and differentiation within stem cell populations. In Caenorhabditis elegans, the germline is the only tissue that is maintained by stem-like cells into adulthood. In the current study, we investigated the role played by a member of the Homeodomain interacting protein kinase (HIPK) family of serine/threonine kinases, HPK-1, in the development and maintenance of the C. elegans germline. RESULTS: We report that HPK-1 is required for promotion of germline proliferation during development and into adulthood. Additionally, we show that HPK-1 is required in the soma for regulation of germline proliferation. We also show that HPK-1 is a predominantly nuclear protein expressed in several somatic tissues including germline-interacting somatic cells. CONCLUSIONS: Our observations are consistent with a conserved role for HIPKs in the control of cellular proliferation and identify a new context for such control in germ cell proliferation.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Células Germinativas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Proliferação de Células , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Proteínas Serina-Treonina Quinases/genética
14.
Diabetes ; 62(8): 2728-37, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23633521

RESUMO

Krüppel-like factor 3 (KLF3) is a transcriptional regulator that we have shown to be involved in the regulation of adipogenesis in vitro. Here, we report that KLF3-null mice are lean and protected from diet-induced obesity and glucose intolerance. On a chow diet, plasma levels of leptin are decreased, and adiponectin is increased. Despite significant reductions in body weight and adiposity, wild-type and knockout animals show equivalent energy intake, expenditure, and excretion. To investigate the molecular events underlying these observations, we used microarray analysis to compare gene expression in Klf3(+/+) and Klf3(-/-) tissues. We found that mRNA expression of Fam132a, which encodes a newly identified insulin-sensitizing adipokine, adipolin, is significantly upregulated in the absence of KLF3. We confirmed that KLF3 binds the Fam132a promoter in vitro and in vivo and that this leads to repression of promoter activity. Further, plasma adipolin levels were significantly increased in Klf3(-/-) mice compared with wild-type littermates. Boosting levels of adipolin via targeting of KLF3 offers a novel potential therapeutic strategy for the treatment of insulin resistance.


Assuntos
Adipocinas/genética , Regulação da Expressão Gênica , Fatores de Transcrição Kruppel-Like/genética , Regulação para Cima/genética , Adipocinas/sangue , Adipocinas/metabolismo , Animais , Metabolismo Energético/fisiologia , Fatores de Transcrição Kruppel-Like/sangue , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Camundongos Knockout , Regiões Promotoras Genéticas
15.
J Cell Sci ; 126(Pt 9): 2079-91, 2013 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-23525010

RESUMO

Protein with tau-like repeats (PTL-1) is the sole Caenorhabditis elegans homolog of tau and MAP2, which are members of the mammalian family of microtubule-associated proteins (MAPs). In mammalian neurons, tau and MAP2 are segregated, with tau being mainly localised to the axon and MAP2 mainly to the dendrite. In particular, tau plays a crucial role in pathology, as elevated levels lead to the formation of tau aggregates in many neurodegenerative conditions including Alzheimer's disease. We used PTL-1 in C. elegans to model the biological functions of a tau-like protein without the complication of functional redundancy that is observed among the mammalian MAPs. Our findings indicate that PTL-1 is important for the maintenance of neuronal health as animals age, as well as in the regulation of whole organism lifespan. In addition, gene dosage of PTL-1 is crucial because variations from wild-type levels are detrimental. We also observed that human tau is unable to robustly compensate for loss of PTL-1, although phenotypes observed in tau transgenic worms are dependent on the presence of endogenous PTL-1. Our data suggest that some of the effects of tau pathology result from the loss of physiological tau function and not solely from a toxic gain-of-function due to accumulation of tau.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Longevidade/fisiologia , Proteínas Associadas aos Microtúbulos/metabolismo , Neurônios/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Animais Geneticamente Modificados/genética , Animais Geneticamente Modificados/metabolismo , Caenorhabditis elegans/citologia , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Dosagem de Genes , Humanos , Proteínas Associadas aos Microtúbulos/genética , Neurônios/citologia , Proteínas tau/biossíntese , Proteínas tau/genética
16.
Dev Biol ; 329(1): 16-24, 2009 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-19232338

RESUMO

Members of the Hox gene family encode transcription factors that specify positional identity along the anterior-posterior axis of nearly all metazoans. One among the Caenorhabditis elegans Hox genes is egl-5. A deletion allele of egl-5 was isolated in a screen for animals which fail to develop swollen tails when exposed to the bacterial pathogen Microbacterium nematophilum. We show that compromised rectal development, which occurs as a result of loss of egl-5 function, results in a failure of rectal epithelial cells to express the ERK MAP kinase mpk-1, which was previously shown to mediate tail-swelling in response to bacterial infection. Tissue-specific rescue experiments demonstrated that egl-5 and mpk-1 act autonomously in rectal cells in the morphological response. The weak egl-5 allele (n1439), which does not compromise rectal development, fails to affect tail-swelling. We find that this allele carries an inserted repeat element approximately 13.8 kb upstream of the egl-5 open reading frame, which specifically disrupts the cell-specific expression of this gene in HSN egg-laying neurons. Together these findings extend the complexity of regulation and function of Hox genes in C. elegans and demonstrate the importance of their tissue-specific expression for correct development and response to infection.


Assuntos
Proteínas de Caenorhabditis elegans/fisiologia , Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiologia , Genes de Helmintos , Genes Homeobox , Proteínas de Homeodomínio/fisiologia , Fatores de Transcrição/fisiologia , Actinomycetales/patogenicidade , Animais , Animais Geneticamente Modificados , Infecções Bacterianas , Sequência de Bases , Caenorhabditis elegans/crescimento & desenvolvimento , Transtornos do Desenvolvimento Sexual/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Fluorescência Verde/metabolismo , Dados de Sequência Molecular , Reto/embriologia , Reto/microbiologia , Deleção de Sequência
17.
J Mol Biol ; 375(1): 1-11, 2008 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-18005989

RESUMO

The C-terminal binding proteins (CtBPs) play roles in diverse cellular processes including transcriptional regulation, Golgi membrane fission, and synaptic ribbon formation. In the context of transcriptional regulation, they function as corepressors, interacting with promoter-bound transcription factors and recruiting a large protein complex that contains chromatin-modifying enzymes. We recently described the structure of a Thanatos-associated protein (THAP) domain that is found in a new member of the CtBP family, the Caenorhabditis elegans CTBP-1 protein. We have identified additional THAP domain-containing CtBPs in the nematode, echinoderm, and cephalochordate lineages. The distribution of these lineages within the animal kingdom suggests that the ancestral form of the animal CtBPs may have contained a THAP domain that was subsequently lost in the vertebrate and arthropod lineages. We also provide functional data indicating that CTBP-1 represses gene expression and homodimerizes and interacts with PXDLS-containing partner proteins, three key features of the previously characterized animal CtBPs. CTBP-1 is therefore the founding member of a new subgroup within the CtBP corepressor family, the THAP domain-containing CtBPs.


Assuntos
Proteínas de Caenorhabditis elegans/química , Caenorhabditis elegans/química , Proteínas Repressoras/química , Oxirredutases do Álcool/química , Oxirredutases do Álcool/genética , Processamento Alternativo , Animais , Proteínas de Caenorhabditis elegans/genética , DNA de Helmintos/genética , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Dimerização , Genes de Helmintos , Modelos Genéticos , Mutação , Filogenia , Ligação Proteica , Estrutura Terciária de Proteína , Análise de Sequência de DNA
18.
J Mol Biol ; 366(2): 382-90, 2007 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-17174978

RESUMO

The THAP (Thanatos-associated protein) domain is a recently discovered zinc-binding domain found in proteins involved in transcriptional regulation, cell-cycle control, apoptosis and chromatin modification. It contains a single zinc atom ligated by cysteine and histidine residues within a Cys-X(2-4)-Cys-X(35-53)-Cys-X(2)-His consensus. We have determined the NMR solution structure of the THAP domain from Caenorhabditis elegans C-terminal binding protein (CtBP) and show that it adopts a fold containing a treble clef motif, bearing similarity to the zinc finger-associated domain (ZAD) from Drosophila Grauzone. The CtBP THAP domain contains a large, positively charged surface patch and we demonstrate that this domain can bind to double-stranded DNA in an electrophoretic mobility-shift assay. These data, together with existing reports, indicate that THAP domains might exhibit a functional diversity similar to that observed for classical and GATA-type zinc fingers.


Assuntos
Oxirredutases do Álcool/química , Proteínas de Caenorhabditis elegans/química , Proteínas de Ligação a DNA/química , Oxirredutases do Álcool/fisiologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Proteínas de Ligação a DNA/fisiologia , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos , Soluções , Relação Estrutura-Atividade
19.
Genetics ; 171(3): 1033-45, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16079230

RESUMO

Interactions with bacteria play a major role in immune responses, ecology, and evolution of all animals, but they have been neglected until recently in the case of C. elegans. We report a genetic investigation of the interaction of C. elegans with the nematode-specific pathogen Microbacterium nematophilum, which colonizes the rectum and causes distinctive tail swelling in its host. A total of 121 mutants with altered response to infection were isolated from selections or screens for a bacterially unswollen (Bus) phenotype, using both chemical and transposon mutagenesis. Some of these correspond to known genes, affecting either bacterial adhesion or colonization (srf-2, srf-3, srf-5) or host swelling response (sur-2, egl-5). Most mutants define 15 new genes (bus-1-bus-6, bus-8, bus-10, bus-12-bus-18). The majority of these mutants exhibit little or no rectal infection when challenged with the pathogen and are probably altered in surface properties such that the bacteria can no longer infect worms. A number have corresponding alterations in lectin staining and cuticle fragility. Most of the uninfectable mutants grow better than wild type in the presence of the pathogen, but the sur-2 mutant is hypersensitive, indicating that the tail-swelling response is associated with a specific defense mechanism against this pathogen.


Assuntos
Caenorhabditis elegans/genética , Caenorhabditis elegans/microbiologia , Actinomycetales/patogenicidade , Infecções por Actinomycetales/microbiologia , Animais , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Mapeamento Cromossômico , Exorribonucleases/genética , Exorribonucleases/metabolismo , Marcadores Genéticos , Predisposição Genética para Doença , Lectinas/metabolismo , Masculino , Mutação , Fenótipo
20.
Curr Biol ; 14(14): 1256-61, 2004 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-15268855

RESUMO

The nematode Caenorhabditis elegans is proving to be an attractive model organism for investigating innate immune responses to infection. Among the known pathogens of C. elegans is the bacterium Microbacterium nematophilum, which adheres to the nematode rectum and postanal cuticle, inducing swelling of the underlying hypodermal tissue and causing mild constipation. We find that on infection by M. nematophilum, an extracellular signal-regulated kinase (ERK) mitogen-activated protein (MAP) kinase cascade mediates tail swelling and protects C. elegans from severe constipation, which would otherwise arrest development and cause sterility. Involvement in pathogen defense represents a new role for ERK MAP kinase signaling in this organism.


Assuntos
Actinomycetales/fisiologia , Caenorhabditis elegans/imunologia , Expressão Gênica , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Reto/imunologia , Transdução de Sinais/imunologia , Actinomycetales/imunologia , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/microbiologia , Constipação Intestinal/imunologia , Constipação Intestinal/microbiologia , Proteínas de Choque Térmico/metabolismo , MAP Quinase Quinase Quinase 2 , MAP Quinase Quinase Quinases/metabolismo , Plasmídeos/genética , Plasmídeos/metabolismo , Reto/microbiologia , Cauda/fisiopatologia
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