RESUMO
BACKGROUND: Venom systems are ideal models to study genetic regulatory mechanisms that underpin evolutionary novelty. Snake venom glands are thought to share a common origin, but there are major distinctions between venom toxins from the medically significant snake families Elapidae and Viperidae, and toxin gene regulatory investigations in elapid snakes have been limited. Here, we used high-throughput RNA-sequencing to profile gene expression and microRNAs between active (milked) and resting (unmilked) venom glands in an elapid (Eastern Brown Snake, Pseudonaja textilis), in addition to comparative genomics, to identify cis- and trans-acting regulation of venom production in an elapid in comparison to viperids (Crotalus viridis and C. tigris). RESULTS: Although there is conservation in high-level mechanistic pathways regulating venom production (unfolded protein response, Notch signaling and cholesterol homeostasis), there are differences in the regulation of histone methylation enzymes, transcription factors, and microRNAs in venom glands from these two snake families. Histone methyltransferases and transcription factor (TF) specificity protein 1 (Sp1) were highly upregulated in the milked elapid venom gland in comparison to the viperids, whereas nuclear factor I (NFI) TFs were upregulated after viperid venom milking. Sp1 and NFI cis-regulatory elements were common to toxin gene promoter regions, but many unique elements were also present between elapid and viperid toxins. The presence of Sp1 binding sites across multiple elapid toxin gene promoter regions that have been experimentally determined to regulate expression, in addition to upregulation of Sp1 after venom milking, suggests this transcription factor is involved in elapid toxin expression. microRNA profiles were distinctive between milked and unmilked venom glands for both snake families, and microRNAs were predicted to target a diversity of toxin transcripts in the elapid P. textilis venom gland, but only snake venom metalloproteinase transcripts in the viperid C. viridis venom gland. These results suggest differences in toxin gene posttranscriptional regulation between the elapid P. textilis and viperid C. viridis. CONCLUSIONS: Our comparative transcriptomic and genomic analyses between toxin genes and isoforms in elapid and viperid snakes suggests independent toxin regulation between these two snake families, demonstrating multiple different regulatory mechanisms underpin a venomous phenotype.
Assuntos
Crotalus , MicroRNAs , Toxinas Biológicas , Serpentes Peçonhentas , Viperidae , Humanos , Animais , Elapidae/genética , Venenos de Serpentes/química , Venenos de Serpentes/genética , Venenos de Serpentes/metabolismo , Venenos Elapídicos/química , Venenos Elapídicos/genética , Venenos Elapídicos/metabolismo , Viperidae/genética , Viperidae/metabolismo , Transcriptoma , Fatores de Transcrição/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismoRESUMO
In the earliest stages of animal development following fertilization, maternally deposited mRNAs direct biological processes to the point of zygotic genome activation (ZGA). These maternal mRNAs undergo cytoplasmic polyadenylation (CPA), suggesting translational control of their activation. To elucidate the biological role of CPA during embryogenesis, we performed genome-wide polysome profiling at several stages of zebrafish development. Our analysis revealed a correlation between CPA and polysome-association dynamics, demonstrating a coupling of translation to the CPA of maternal mRNAs. Pan-embryonic CPA inhibition disrupted the maternal-to-zygotic transition (MZT), causing a failure of developmental progression beyond the mid-blastula transition and changes in global gene expression that indicated a failure of ZGA and maternal mRNA clearance. Among the genes that were differentially expressed were those encoding chromatin modifiers and key transcription factors involved in ZGA, including nanog, pou5f3 and sox19b, which have distinct CPA dynamics. Our results establish the necessity of CPA for ensuring progression of the MZT. The RNA-seq data generated in this study represent a valuable zebrafish resource for the discovery of novel elements of the early embryonic transcriptome.
Assuntos
Citoplasma/metabolismo , Poliadenilação/fisiologia , Biossíntese de Proteínas/fisiologia , RNA Mensageiro/metabolismo , Proteínas de Peixe-Zebra/biossíntese , Peixe-Zebra/embriologia , Zigoto/metabolismo , Animais , Feminino , RNA Mensageiro/genética , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Zigoto/citologiaRESUMO
The Singapore Preconception Study of Long-Term Maternal and Child Outcomes (S-PRESTO) is a preconception, longitudinal cohort study that aims to study the effects of nutrition, lifestyle, and maternal mood prior to and during pregnancy on the epigenome of the offspring and clinically important outcomes including duration of gestation, fetal growth, metabolic and neural phenotypes in the offspring. Between February 2015 and October 2017, the S-PRESTO study recruited 1039 Chinese, Malay or Indian (or any combinations thereof) women aged 18-45 years and who intended to get pregnant and deliver in Singapore, resulting in 1032 unique participants and 373 children born in the cohort. The participants were followed up for 3 visits during the preconception phase and censored at 12 months of follow up if pregnancy was not achieved (N = 557 censored). Women who successfully conceived (N = 475) were characterised at gestational weeks 6-8, 11-13, 18-21, 24-26, 27-28 and 34-36. Follow up of their index offspring (N = 373 singletons) is on-going at birth, 1, 3 and 6 weeks, 3, 6, 12, 18, 24 and 36 months and beyond. Women are also being followed up post-delivery. Data is collected via interviewer-administered questionnaires, metabolic imaging (magnetic resonance imaging), standardized anthropometric measurements and collection of diverse specimens, i.e. blood, urine, buccal smear, stool, skin tapes, epithelial swabs at numerous timepoints. S-PRESTO has extensive repeated data collected which include genetic and epigenetic sampling from preconception which is unique in mother-offspring epidemiological cohorts. This enables prospective assessment of a wide array of potential determinants of future health outcomes in women from preconception to post-delivery and in their offspring across the earliest development from embryonic stages into early childhood. In addition, the S-PRESTO study draws from the three major Asian ethnic groups that represent 50% of the global population, increasing the relevance of its findings to global efforts to address non-communicable diseases.
Assuntos
Estilo de Vida , Comportamento Materno , Estado Nutricional , Vigilância da População/métodos , Cuidado Pré-Concepcional/estatística & dados numéricos , Cuidado Pré-Natal/estatística & dados numéricos , Adolescente , Adulto , Afeto , Feminino , Humanos , Estudos Longitudinais , Fenômenos Fisiológicos da Nutrição Materna , Pessoa de Meia-Idade , Gravidez , Resultado da Gravidez/epidemiologia , Medição de Risco , Singapura/epidemiologia , Adulto JovemRESUMO
BACKGROUND: TNF-α, a pro-inflammatory cytokine is one of the major contributors for metabolic syndromes including insulin resistance, obesity, type II diabetes etc. The role of alternative splicing, a post-transcriptional regulation of gene expression on the onset of these syndromes is poorly understood. However, the role of alternative splicing, which more than 95% of all exons in eukaryotic cells undergo in several other diseases including cancer and muscle dystrophy, has been elucidated. In this study we aim to investigate the role of alternative splicing in pathways leading to metabolic syndromes mediated by TNF-α. METHODS: A genome wide transcriptome analysis was carried out using Illumina platform. Results were validated using RT-PCR analysis. Various bioinformatics tools and databases (for example IPA, KEGG, STRING etc) were used for the pathway and interactome analysis. CURRENT FINDINGS: Transcriptome wide analysis revealed that TNF-α treatment in vitro causes a significant change in expression of 228 genes at the level of alternative splicing. Regulation of some of these genes was validated in different cell lines. Pathway analysis showed at least 15% of the alternatively spliced genes fall under the contributory pathways leading to different metabolic syndromes, among which the maximally interconnected genes were transcription regulators. CONCLUSION: These findings suggest that TNF-α.-mediated alternative splicing plays a crucial role in regulating various genes involved in pathways connected to metabolic syndromes.
Assuntos
Processamento Alternativo/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/genética , Síndrome Metabólica/metabolismo , Transcriptoma/genética , Fator de Necrose Tumoral alfa/farmacologia , Animais , Linhagem Celular , Biologia Computacional , Bases de Dados Genéticas , Éxons , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Redes e Vias Metabólicas/efeitos dos fármacos , Redes e Vias Metabólicas/genética , Síndrome Metabólica/genética , Camundongos , Células Musculares/efeitos dos fármacos , Células Musculares/metabolismo , Músculo Esquelético/citologia , Músculo Esquelético/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Small molecule drugs bind to a pocket in disease causing target proteins based on complementarity in shape and physicochemical properties. There is a likelihood that other proteins could have binding sites that are structurally similar to the target protein. Binding to these other proteins could alter their activities leading to off target effects of the drug. One such small molecule drug Nutlin binds the protein MDM2, which is upregulated in several types of cancer and is a negative regulator of the tumor suppressor protein p53. To investigate the off target effects of Nutlin, we present here a shape-based data mining effort. We extracted the binding pocket of Nutlin from the crystal structure of Nutlin bound MDM2. We next mined the protein structural database (PDB) for putative binding pockets in other human protein structures that were similar in shape to the Nutlin pocket in MDM2 using our topology-independent structural superimposition tool CLICK. We detected 49 proteins which have binding pockets that were structurally similar to the Nutlin binding site of MDM2. All of the potential complexes were evaluated using molecular mechanics and AutoDock Vina docking scores. Further, molecular dynamics simulations were carried out on four of the predicted Nutlin-protein complexes. The binding of Nutlin to one of these proteins, gamma glutamyl hydrolase, was also experimentally validated by a thermal shift assay. These findings provide a platform for identifying potential off-target effects of existing/new drugs and also opens the possibilities for repurposing drugs/ligands.
Assuntos
Imidazóis/farmacologia , Terapia de Alvo Molecular , Proteína Supressora de Tumor p53/metabolismo , Sítios de Ligação , Simulação de Dinâmica Molecular , Conformação Proteica , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Temperatura , Proteína Supressora de Tumor p53/químicaRESUMO
Interactions between natural killer (NK) cells and dendritic cells (DCs) aid DC maturation and promote T-cell responses. Here, we have analyzed the response of human NK cells to tumor cells, and we identify a pathway by which NK-DC interactions occur. Gene expression profiling of tumor-responsive NK cells identified the very rapid induction of TNF superfamily member 14 [TNFSF14; also known as homologous to lymphotoxins, exhibits inducible expression, and competes with HSV glycoprotein D for HVEM, a receptor expressed by T lymphocytes (LIGHT)], a cytokine implicated in the enhancement of antitumor responses. TNFSF14 protein expression was induced by three primary mechanisms of NK cell activation, namely, via the engagement of CD16, by the synergistic activity of multiple target cell-sensing NK-cell activation receptors, and by the cytokines IL-2 and IL-15. For antitumor responses, TNFSF14 was preferentially produced by the licensed NK-cell population, defined by the expression of inhibitory receptors specific for self-MHC class I molecules. In contrast, IL-2 and IL-15 treatment induced TNFSF14 production by both licensed and unlicensed NK cells, reflecting the ability of proinflammatory conditions to override the licensing mechanism. Importantly, both tumor- and cytokine-activated NK cells induced DC maturation in a TNFSF14-dependent manner. The coupling of TNFSF14 production to tumor-sensing NK-cell activation receptors links the tumor immune surveillance function of NK cells to DC maturation and adaptive immunity. Furthermore, regulation by NK cell licensing helps to safeguard against TNFSF14 production in response to healthy tissues.
Assuntos
Comunicação Celular/imunologia , Células Dendríticas/imunologia , Vigilância Imunológica , Células Matadoras Naturais/imunologia , Ativação Linfocitária , Membro 14 da Superfamília de Ligantes de Fatores de Necrose Tumoral/imunologia , Técnicas de Cocultura , Células Dendríticas/citologia , Feminino , Proteínas Ligadas por GPI/imunologia , Humanos , Interleucina-15/imunologia , Interleucina-2/imunologia , Células K562 , Células Matadoras Naturais/citologia , Masculino , Neoplasias/imunologia , Receptores de IgG/imunologiaRESUMO
BACKGROUND: The role of microRNAs in gene regulation has been well established. The extent of miRNA regulation also increases with increasing genome complexity. Though the number of genes appear to be equal between human and zebrafish, substantially less microRNAs have been discovered in zebrafish compared to human (miRBase Release 19). It appears that most of the miRNAs in zebrafish are yet to be discovered. RESULTS: We sequenced small RNAs from brain, gut, liver, ovary, testis, eye, heart and embryo of zebrafish. In brain, gut and liver sequencing was done sex specifically. Majority of the sequenced reads (16-62 %) mapped to known miRNAs, with the exception of ovary (5.7 %) and testis (7.8 %). Using the miRNA discovery tool (miRDeep2), we discovered novel miRNAs from the unannotated reads that ranged from 7.6 to 23.0 %, with exceptions of ovary (51.4 %) and testis (55.2 %). The prediction tool identified a total of 459 novel pre-miRNAs. We compared expression of miRNAs between different tissues and between males and females to identify tissue associated and sex associated miRNAs respectively. These miRNAs could serve as putative biomarkers for these tissues. The brain and liver had highest number of tissue associated (22) and sex associated (34) miRNAs, respectively. CONCLUSIONS: This study comprehensively identifies tissue and sex associated miRNAs in zebrafish. Further, we have discovered 459 novel pre-miRNAs (~30 % seed homology to human miRNA) as a genomic resource which can facilitate further investigations to understand miRNA-mRNA gene regulatory networks in zebrafish which will have implications in understanding the function of human homologs.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , MicroRNAs/genética , Análise de Sequência de RNA , Caracteres Sexuais , Peixe-Zebra/genética , Animais , Feminino , Perfilação da Expressão Gênica , Humanos , Masculino , Especificidade de Órgãos , Peixe-Zebra/fisiologiaRESUMO
Mesenchymal stem/stromal cells (MSCs) have been extensively investigated for their regenerative, immune-modulatory, and wound healing properties. While the laboratory studies have suggested that MSC's have a unique potential for modulating the etiopathology of multiple diseases, the results from clinical trials have not been encouraging or reproducible. One of the explanations for such variability is explained by the "art" of isolating and propagating MSCs. Therefore, establishing more than minimal criteria to define MSC would help understand best protocols to isolate, propagate and deliver MSCs. Developing a calibration standard, a database and a set of functional tests would be a better quality metric for MSCs. In this review, we discuss the importance of selecting a standard, issues associated with coming up with such a standard and how these issues can be mitigated.
Assuntos
Separação Celular/normas , Células-Tronco Mesenquimais/citologia , Técnicas de Cultura de Células , Células Cultivadas , Humanos , Transplante de Células-Tronco Mesenquimais/métodos , Padrões de ReferênciaRESUMO
Antibiotics have played a critical role in sustaining and improving livestock production in the past decades, but the emergence of antimicrobial resistance has led several countries to ban or limit their use. Since then, in-feed alternatives have gained a lot of attention but the development of efficacious alternatives implies a better understanding of the mode of action of antibiotic growth promoters (AGP) when administered at subtherapeutic concentrations. In the present study, 120 broiler chickens per group (8 pens/group) were fed for 35 d with either basal feed (control group) or feed supplemented with avilamycin (AGP group; 10 g/1,000 kg of feed). At the end of the trial, the ileum from the small intestine of 5 birds per group was sampled, and RNA were isolated for profiling their transcriptome via RNA sequencing (RNA-Seq). As expected, the growth of chickens in the AGP group was significantly higher than in the control group. Overall, 66 differentially expressed genes (false discovery rate ≤ 0.05 and fold change ≥ 2 or ≤ -2) were found in the ileum of chickens fed avilamycin in comparison with the control group. The functional analysis showed reduced activity of genes related to signaling by interleukins, with IL-22, SOCS3, and certain antimicrobial peptides found multiple times in these pathways in the AGP group at day 35. In addition, higher activity was predicted in a module of genes related to lipid metabolism and transport in the avilamycin group. The use of RNA-Seq allowed a snapshot of the whole transcriptome at day 35 and aimed at delivering additional data on the host-centric hypothesis regarding the mode of action of AGP (i.e. immunomodulation, reduction of the immunological stress).
Assuntos
Ração Animal , Antibacterianos/administração & dosagem , Galinhas , Íleo/química , Oligossacarídeos/administração & dosagem , Transcriptoma , Ração Animal/análise , Animais , Galinhas/crescimento & desenvolvimento , Dieta/veterinária , Análise de Sequência de RNA/veterináriaRESUMO
BACKGROUND: It has been apparent in the last few years that small non coding RNAs (ncRNA) play a very significant role in biological regulation. Among these microRNAs (miRNAs), 22-23 nucleotide small regulatory RNAs, have been a major object of study as these have been found to be involved in some basic biological processes. So far about 706 miRNAs have been identified in humans alone. However, it is expected that there may be many more miRNAs encoded in the human genome. In this report, a "context-sensitive" Hidden Markov Model (CSHMM) to represent miRNA structures has been proposed and tested extensively. We also demonstrate how this model can be used in conjunction with filters as an ab initio method for miRNA identification. RESULTS: The probabilities of the CSHMM model were estimated using known human miRNA sequences. A classifier for miRNAs based on the likelihood score of this "trained" CSHMM was evaluated by: (a) cross-validation estimates using known human sequences, (b) predictions on a dataset of known miRNAs, and (c) prediction on a dataset of non coding RNAs. The CSHMM is compared with two recently developed methods, miPred and CID-miRNA. The results suggest that the CSHMM performs better than these methods. In addition, the CSHMM was used in a pipeline that includes filters that check for the presence of EST matches and the presence of Drosha cutting sites. This pipeline was used to scan and identify potential miRNAs from the human chromosome 19. It was also used to identify novel miRNAs from small RNA sequences of human normal leukocytes obtained by the Deep sequencing (Solexa) methodology. A total of 49 and 308 novel miRNAs were predicted from chromosome 19 and from the small RNA sequences respectively. CONCLUSION: The results suggest that the CSHMM is likely to be a useful tool for miRNA discovery either for analysis of individual sequences or for genome scan. Our pipeline, consisting of a CSHMM and filters to reduce false positives shows promise as an approach for ab initio identification of novel miRNAs.
Assuntos
Genômica/métodos , Cadeias de Markov , MicroRNAs/química , RNA/químicaRESUMO
BACKGROUND: MicroRNAs are a class of small non-coding RNAs that regulate mRNA expression at the post - transcriptional level and thereby many fundamental biological processes. A number of methods, such as multiplex polymerase chain reaction, microarrays have been developed for profiling levels of known miRNAs. These methods lack the ability to identify novel miRNAs and accurately determine expression at a range of concentrations. Deep or massively parallel sequencing methods are providing suitable platforms for genome wide transcriptome analysis and have the ability to identify novel transcripts. RESULTS: The results of analysis of small RNA sequences obtained by Solexa technology of normal peripheral blood mononuclear cells, tumor cell lines K562 and HL60 are presented. In general K562 cells displayed overall low level of miRNA population and also low levels of DICER. Some of the highly expressed miRNAs in the leukocytes include several members of the let-7 family, miR-21, 103, 185, 191 and 320a. Comparison of the miRNA profiles of normal versus K562 or HL60 cells revealed a specific set of differentially expressed molecules. Correlation of the miRNA with that of mRNA expression profiles, obtained by microarray, revealed a set of target genes showing inverse correlation with miRNA levels. Relative expression levels of individual miRNAs belonging to a cluster were found to be highly variable. Our computational pipeline also predicted a number of novel miRNAs. Some of the predictions were validated by Real-time RT-PCR and or RNase protection assay. Organization of some of the novel miRNAs in human genome suggests that these may also be part of existing clusters or form new clusters. CONCLUSIONS: We conclude that about 904 miRNAs are expressed in human leukocytes. Out of these 370 are novel miRNAs. We have identified miRNAs that are differentially regulated in normal PBMC with respect to cancer cells, K562 and HL60. Our results suggest that post - transcriptional processes may play a significant role in regulating levels of miRNAs in tumor cells. The study also provides a customized automated computation pipeline for miRNA profiling and identification of novel miRNAs; even those that are missed out by other existing pipelines. The Computational Pipeline is available at the website: http://mirna.jnu.ac.in/deep_sequencing/deep_sequencing.html.
Assuntos
Perfilação da Expressão Gênica/métodos , Leucócitos Mononucleares/metabolismo , MicroRNAs/genética , Células HL-60 , Humanos , Íntrons/genética , Células K562 , MicroRNAs/biossíntese , Análise de Sequência de DNARESUMO
Current opinion views androgens as the pathogenic driver in the miniaturization of hair follicles of androgenetic alopecia by interfering with the dermal papilla. This cannot be the sole cause and therefore it is important for therapeutic and diagnostic purposes to identify additional pathways. Comparative full transcriptome profile analysis of the hair bulb region of normal and miniaturized hair follicles from vertex and occipital region in males with and without androgenetic alopecia revealed that next to the androgen receptor as well the retinoid receptor and particularly the PPAR pathway is involved in progressive hair miniaturization. We demonstrate the concurrent up-regulation of PPARGC1a in the epithelial compartment and androgen receptor in the dermal papilla of miniaturized hair. Dynamic Ppargc1a expression in the mouse hair cycle suggests a possible role in regulating hair growth and differentiation. This is supported by reduced proliferation of human dermal papilla and predominantly epithelial keratinocytes after incubation with AICAR, the agonist for AMPK signaling which activates PPARGC1a and serves as co-activator of PPARγ. In addition, miRNA profiling shows enrichment of miRNA-targeted genes in retinoid receptors and PPARGC1α/PPARγ signaling, and antigen presentation pathways.
Assuntos
Alopecia/metabolismo , Regulação da Expressão Gênica , Folículo Piloso/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/biossíntese , Transdução de Sinais , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Alopecia/genética , Alopecia/patologia , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/metabolismo , Animais , Linhagem Celular Transformada , Folículo Piloso/patologia , Humanos , Camundongos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Ribonucleotídeos/genética , Ribonucleotídeos/metabolismoAssuntos
MicroRNAs , Psoríase , Dermatopatias , Humanos , Regulação para Baixo , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Hiperplasia/genética , Interleucina-17/genética , Interleucina-17/metabolismo , MicroRNAs/genética , Psoríase/genética , Psoríase/metabolismoRESUMO
The causes of impaired skeletal muscle mass and strength during aging are well-studied in healthy populations. Less is known on pathological age-related muscle wasting and weakness termed sarcopenia, which directly impacts physical autonomy and survival. Here, we compare genome-wide transcriptional changes of sarcopenia versus age-matched controls in muscle biopsies from 119 older men from Singapore, Hertfordshire UK and Jamaica. Individuals with sarcopenia reproducibly demonstrate a prominent transcriptional signature of mitochondrial bioenergetic dysfunction in skeletal muscle, with low PGC-1α/ERRα signalling, and downregulation of oxidative phosphorylation and mitochondrial proteostasis genes. These changes translate functionally into fewer mitochondria, reduced mitochondrial respiratory complex expression and activity, and low NAD+ levels through perturbed NAD+ biosynthesis and salvage in sarcopenic muscle. We provide an integrated molecular profile of human sarcopenia across ethnicities, demonstrating a fundamental role of altered mitochondrial metabolism in the pathological loss of skeletal muscle mass and function in older people.
Assuntos
Envelhecimento/fisiologia , Mitocôndrias/patologia , Músculo Esquelético/patologia , NAD/biossíntese , Sarcopenia/patologia , Idoso , Idoso de 80 Anos ou mais , Biópsia , Estudos de Casos e Controles , Metabolismo Energético/fisiologia , Humanos , Jamaica , Masculino , Pessoa de Meia-Idade , Mitocôndrias/metabolismo , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Oxirredução , Fosforilação Oxidativa , Estresse Oxidativo/fisiologia , Proteostase , Sarcopenia/etnologia , Singapura , Reino UnidoRESUMO
microRNAs (miRNA) are a class of non-protein coding functional RNAs that are thought to regulate expression of target genes by direct interaction with mRNAs. miRNAs have been identified through both experimental and computational methods in a variety of eukaryotic organisms. Though these approaches have been partially successful, there is a need to develop more tools for detection of these RNAs as they are also thought to be present in abundance in many genomes. In this report we describe a tool and a web server, named CID-miRNA, for identification of miRNA precursors in a given DNA sequence, utilising secondary structure-based filtering systems and an algorithm based on stochastic context free grammar trained on human miRNAs. CID-miRNA analyses a given sequence using a web interface, for presence of putative miRNA precursors and the generated output lists all the potential regions that can form miRNA-like structures. It can also scan large genomic sequences for the presence of potential miRNA precursors in its stand-alone form. The web server can be accessed at http://mirna.jnu.ac.in/cidmirna/.
Assuntos
Biologia Computacional/métodos , Genoma Humano , MicroRNAs/genética , Análise de Sequência de RNA/métodos , Software , Sequência de Bases , Biologia Computacional/instrumentação , Humanos , Internet , Dados de Sequência Molecular , Análise de Sequência de RNA/instrumentaçãoRESUMO
Several available online tools provide network growing functions where an algorithm utilizing different data sources suggests additional genes/proteins that should connect an input gene set into functionally meaningful networks. Using the well-studied system of influenza host interactions, we compare the network growing function of two free tools GeneMANIA and STRING and the commercial IPA for their performance of recovering known influenza A virus host factors previously identified from siRNA screens. The result showed that given small (~30 genes) or medium (~150 genes) input sets all three network growing tools detect significantly more known host factors than random human genes with STRING overall performing strongest. Extending the networks with all the three tools significantly improved the detection of GO biological processes of known host factors compared to not growing networks. Interestingly, the rate of identification of true host factors using computational network growing is equal or better to doing another experimental siRNA screening study which could also be true and applied to other biological pathways/processes.
Assuntos
Benchmarking , Biologia Computacional/métodos , Redes Reguladoras de Genes , Interações Hospedeiro-Patógeno/genética , Vírus/metabolismo , Algoritmos , Ontologia Genética , Humanos , RNA Interferente Pequeno/metabolismo , Transdução de SinaisRESUMO
Epithelial carcinomas are well known to activate a prolonged wound-healing program that promotes malignant transformation. Wound closure requires the activation of keratinocyte migration via a dual-state molecular switch. This switch involves production of either the anti-migratory microRNA miR-198 or the pro-migratory follistatin-like 1 (FSTL1) protein from a single transcript; miR-198 expression in healthy skin is down-regulated in favor of FSTL1 upon wounding, which enhances keratinocyte migration and promotes re-epithelialization. Here, we reveal a defective molecular switch in head and neck squamous cell carcinoma (HNSCC). This defect shuts off miR-198 expression in favor of sustained FSTL1 translation, driving metastasis through dual parallel pathways involving DIAPH1 and FSTL1. DIAPH1, a miR-198 target, enhances directional migration through sequestration of Arpin, a competitive inhibitor of Arp2/3 complex. FSTL1 blocks Wnt7a-mediated repression of extracellular signal-regulated kinase phosphorylation, enabling production of MMP9, which degrades the extracellular matrix and facilitates metastasis. The prognostic significance of the FSTL1-DIAPH1 gene pair makes it an attractive target for therapeutic intervention.
Assuntos
Transformação Celular Neoplásica/metabolismo , Fator de Crescimento Epidérmico/fisiologia , Proteínas Relacionadas à Folistatina/fisiologia , MicroRNAs/fisiologia , Cicatrização/fisiologia , Animais , Western Blotting , Carcinoma de Células Escamosas/metabolismo , Proliferação de Células , Feminino , Genes de Troca/fisiologia , Neoplasias de Cabeça e Pescoço/metabolismo , Imunoprecipitação , Espectrometria de Massas , Camundongos Endogâmicos NODRESUMO
The presence of multiple variants for many mRNAs is a major contributor to protein diversity. The processing of these variants is tightly controlled in a cell-type specific manner and has a significant impact on gene expression control. Here we investigate the differential translation rates of individual mRNA variants in embryonic stem cells (ESCs) and in ESC derived Neural Precursor Cells (NPCs) using polysome profiling coupled to RNA sequencing. We show that there are a significant number of detectable mRNA variants in ESCs and NPCs and that many of them show variant specific translation rates. This is correlated with differences in the UTRs of the variants with the 5'UTR playing a predominant role. We suggest that mRNA variants that contain alternate UTRs are under different post-transcriptional controls. This is likely due to the presence or absence of miRNA and protein binding sites that regulate translation rate. This highlights the importance of addressing translation rate when using mRNA levels as a read out of protein abundance. Additional analysis shows that many annotated non-coding mRNAs are present on the polysome fractions in ESCs and NPCs. We believe that the use of polysome fractionation coupled to RNA sequencing is a useful method for analysis of the translation state of many different RNAs in the cell.
Assuntos
Células-Tronco Embrionárias/fisiologia , Biossíntese de Proteínas , RNA Mensageiro/genética , Regiões 3' não Traduzidas , Regiões 5' não Traduzidas , Animais , Diferenciação Celular , Células Cultivadas , Células-Tronco Embrionárias/citologia , Regulação da Expressão Gênica no Desenvolvimento , Fator de Crescimento Insulin-Like II/genética , Camundongos , Células-Tronco Neurais/fisiologia , Polirribossomos/genética , Polirribossomos/metabolismo , Splicing de RNA , Ribonucleoproteínas/genética , Análise de Sequência de RNARESUMO
Development of myopia is associated with large-scale changes in ocular tissue gene expression. Although differential expression of coding genes underlying development of myopia has been a subject of intense investigation, the role of non-coding genes such as microRNAs in the development of myopia is largely unknown. In this study, we explored myopia-associated miRNA expression profiles in the retina and sclera of C57Bl/6J mice with experimentally induced myopia using microarray technology. We found a total of 53 differentially expressed miRNAs in the retina and no differences in miRNA expression in the sclera of C57BL/6J mice after 10 days of visual form deprivation, which induced -6.93 ± 2.44 D (p < 0.000001, n = 12) of myopia. We also identified their putative mRNA targets among mRNAs found to be differentially expressed in myopic retina and potential signaling pathways involved in the development of form-deprivation myopia using miRNA-mRNA interaction network analysis. Analysis of myopia-associated signaling pathways revealed that myopic response to visual form deprivation in the retina is regulated by a small number of highly integrated signaling pathways. Our findings highlighted that changes in microRNA expression are involved in the regulation of refractive eye development and predicted how they may be involved in the development of myopia by regulating retinal gene expression.
Assuntos
MicroRNAs/genética , Miopia/genética , RNA Mensageiro/genética , Animais , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/metabolismo , Miopia/etiologia , Miopia/metabolismo , Estimulação Luminosa , RNA Mensageiro/metabolismo , Retina/metabolismo , Esclera/metabolismo , Privação Sensorial , Transdução de Sinais/genéticaRESUMO
Increased visceral fat, rather than subcutaneous fat, during the onset of obesity is associated with a higher risk of developing metabolic diseases. The inherent adipogenic properties of human adipose-derived stem cells (ASCs) from visceral depots are compromised compared with those of ASCs from subcutaneous depots, but little is known about the underlying mechanisms. Using ontological analysis of global gene expression studies, we demonstrate that many genes involved in retinoic acid (RA) synthesis or regulated by RA are differentially expressed in human tissues and ASCs from subcutaneous and visceral fat. The endogenous level of RA is higher in visceral ASCs; this is associated with upregulation of the RA synthesis gene through the visceral-specific developmental factor WT1. Excessive RA-mediated activity impedes the adipogenic capability of ASCs at early but not late stages of adipogenesis, which can be reversed by antagonism of RA receptors or knockdown of WT1. Our results reveal the developmental origin of adipocytic properties and the pathophysiological contributions of visceral fat depots.