The Experts below are selected from a list of 42285 Experts worldwide ranked by ideXlab platform
Niehrs Christof - One of the best experts on this subject based on the ideXlab platform.
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The 18S Ribosomal RNA m6A methyltransferase Mettl5 is required for normal walking behavior in Drosophila
'EMBO', 2020Co-Authors: Leismann Jessica, Spagnuolo Mariangela, Pradhan Mihika, Wacheul Ludivine, Vu, Minh Anh, Musheev Michael, Mier Pablo, Andrade-navarro, Miguel Angel, Graille Marc, Niehrs ChristofAbstract:RNA modifications have recently emerged as an important layer of gene regulation. N6-methyladenosine (m6A) is the most prominent modification on eukaryotic messenger RNA and has also been found on noncoding RNA, including Ribosomal and small nuclear RNA. Recently, several m6A methyltransferases were identified, uncovering the specificity of m6A deposition by structurally distinct enzymes. In order to discover additional m6A enzymes, we performed an RNAi screen to deplete annotated orthologs of human methyltransferase-like proteins (METTLs) in Drosophila cells and identified CG9666, the ortholog of human METTL5. We show that CG9666 is required for specific deposition of m6A on 18S Ribosomal RNA via direct interaction with the Drosophila ortholog of human TRMT112, CG12975. Depletion of CG9666 yields a subsequent loss of the 18S rRNA m6A modification, which lies in the vicinity of the ribosome decoding center; however, this does not compromise rRNA maturation. Instead, a loss of CG9666-mediated m6A impacts fly behavior, providing an underlying molecular mechanism for the reported human phenotype in intellectual disability. Thus, our work expands the repertoire of m6A methyltransferases, demonstrates the specialization of these enzymes, and further addresses the significance of Ribosomal RNA modifications in gene expression and animal behavior.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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The 18S Ribosomal RNA m 6 A methyltransferase Mettl5 is required for normal walking behavior in Drosophila
'EMBO', 2020Co-Authors: Leismann Jessica, Spagnuolo Mariangela, Pradhan Mihika, Wacheul Ludivine, Musheev Michael, Mier Pablo, Graille Marc, Anh Vu Minh, Andrade-navarro, Miguel A., Niehrs ChristofAbstract:InteRNAtional audienceRNA modifications have recently emerged as an important layer of gene regulation. N6-methyladenosine (m6 A) is the most prominent modification on eukaryotic messenger RNA and has also been found on noncoding RNA, including Ribosomal and small nuclear RNA. Recently, several m6 A methyltransferases were identified, uncovering the specificity of m6 A deposition by structurally distinct enzymes. In order to discover additional m6 A enzymes, we performed an RNAi screen to deplete annotated orthologs of human methyltransferase-like proteins (METTLs) in Drosophila cells and identified CG9666, the ortholog of human METTL5. We show that CG9666 is required for specific deposition of m6 A on 18S Ribosomal RNA via direct interaction with the Drosophila ortholog of human TRMT112, CG12975. Depletion of CG9666 yields a subsequent loss of the 18S rRNA m6 A modification, which lies in the vicinity of the ribosome decoding center; however, this does not compromise rRNA maturation. Instead, a loss of CG9666-mediated m6 A impacts fly behavior, providing an underlying molecular mechanism for the reported human phenotype in intellectual disability. Thus, our work expands the repertoire of m6 A methyltransferases, demonstrates the specialization of these enzymes, and further addresses the significance of Ribosomal RNA modifications in gene expression and animal behavior
Ziheng Yang - One of the best experts on this subject based on the ideXlab platform.
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effects of models of rate evolution on estimation of divergence dates with special reference to the metazoan 18S Ribosomal RNA phylogeny
Systematic Biology, 2002Co-Authors: Stephane Arisbrosou, Ziheng YangAbstract:The molecular clock, i.e., constancy of the rate of evolution over time, is commonly assumed in estimating divergence dates. However, this assumption is often violated and has drastic effects on date estimation. Recently, a number of attempts have been made to relax the clock assumption. One approach is to use maximum likelihood, which assigns rates to branches and allows the estimation of both rates and times. An alteRNAtive is the Bayes approach, which models the change of the rate over time. A number of models of rate change have been proposed. We have extended and evaluated models of rate evolution, i.e., the lognormal and its recent variant, along with the gamma, the exponential, and the Ornstein-Uhlenbeck processes. These models were first applied to a small hominoid data set, where an empirical Bayes approach was used to estimate the hyperparameters that measure the amount of rate variation. Estimation of divergence times was sensitive to these hyperparameters, especially when the assumed model is close to the clock assumption. The rate and date estimates varied little from model to model, although the posterior Bayes factor indicated the Ornstein-Uhlenbeck process outperformed the other models. To demonstrate the importance of allowing for rate change across lineages, this general approach was used to analyze a larger data set consisting of the 18S Ribosomal RNA gene of 39 metazoan species. We obtained date estimates consistent with paleontological records, the deepest split within the group being about 560 million years ago. Estimates of the rates were in accordance with the Cambrian explosion hypothesis and suggested some more recent lineage-specific bursts of evolution.
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effects of models of rate evolution on estimation of divergence dates with special reference to the metazoan 18S Ribosomal RNA phylogeny
Systematic Biology, 2002Co-Authors: Stephane Arisbrosou, Ziheng YangAbstract:The molecular clock, i.e., constancy of the rate of evolution over time, is commonly as- sumed in estimating divergence dates. However, this assumption is often violated and has drastic effects on date estimation. Recently, a number of attempts have been made to relax the clock assump- tion. One approach is to use maximum likelihood, which assigns rates to branches and allows the estimation of both rates and times. An alteRNAtive is the Bayes approach, which models the change of the rate over time. A number of models of rate change have been proposed. We have extended and evaluated models of rate evolution, i.e., the lognormal and its recent variant, along with the gamma, the exponential, and the Ornstein-Uhlenbeck processes. These models were erst applied to a small hominoid data set, where an empirical Bayes approach was used to estimate the hyperparameters that measure the amount of rate variation. Estimation of divergence times was sensitive to these hy- perparameters, especially when the assumed model is close to the clock assumption. The rate and date estimates varied little from model to model, although the posterior Bayes factor indicated the Ornstein-Uhlenbeck process outperformed the other models. To demonstrate the importance of al- lowing for rate change across lineages, this general approach was used to analyze a larger data set consisting of the 18S Ribosomal RNA gene of 39 metazoan species. We obtained date estimates con- sistent with paleontological records, the deepest split within the group being about 560 million years ago.Estimatesof therateswere in accordancewith the Cambrian explosion hypothesisand suggested some more recent lineage-speciec bursts of evolution. (18S rRNA; local molecular clocks; Markov chain Monte Carlo; Metazoa; Metropolis-Hastings algorithm; molecular clock; Ornstein-Uhlenbeck process; phylogeny; posterior Bayes factor; rate of evolution.)
Kwokyung Yuen - One of the best experts on this subject based on the ideXlab platform.
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early diagnosis of exophiala capd peritonitis by 18S Ribosomal RNA gene sequencing and its clinical significance
Diagnostic Microbiology and Infectious Disease, 2003Co-Authors: Susanna K P Lau, Patrick C Y Woo, Siukau Chiu, Kitwah Leung, Raymond W H Yung, Kwokyung YuenAbstract:Phenotypic identification of fungi in clinical microbiology laboratories is often difficult and late, especially for slow growing and rarely encountered fungi. We describe the application of 18S Ribosomal RNA (rRNA) gene sequencing in the early diagnosis of a case of Exophiala peritonitis. A yeast-like fungus was isolated from the dialysate fluid of a 66-year-old man undergoing continuous ambulatory peritoneal dialysis. It grew slowly after 12 days of incubation to yield mature cultures to permit recognition of microscopic features resembling those of Exophiala, a dematiacerous mold. 18S rRNA gene sequencing provided results 12 days earlier than phenotypic identification and revealed 15 base difference (0.9%) between the isolate and Exophiala sp. strain GHP 1205 (GenBank Accession no. AJ232954), indicating that the isolate most closely resembles a strain of Exophiala species. The patient responded to 4 weeks of intravenous amphotericin B therapy. Early identification of the fungus was important for the choice of anti-fungal regimen. As opportunistic fungal infections in immunocompromised patients are globally emerging problems, the development of molecular techniques for fungal identification is crucial for early diagnosis and appropriate treatment.
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early diagnosis of exophiala capd peritonitis by 18S Ribosomal RNA gene sequencing and its clinical significance
Diagnostic Microbiology and Infectious Disease, 2003Co-Authors: Siukau Chiu, Kitwah Leung, Raymond W H Yung, Kwokyung YuenAbstract:Abstract Phenotypic identification of fungi in clinical microbiology laboratoreis is often difficult and late, especially for slow growing and rarely encountered fungi. We describe the application of 18S Ribosomal RNA (rRNA) gene sequencing in the early diagnosis of a case of Exophiala peritonitis. A yeast-like fungus was isolated from the dialysate fluid of a 66-year-old man undergoing continuous ambulatory peritoneal dialysis. It grew slowly after 12 days of incubation to yield mature cultures to permit recognition of microscopic features resembling those of Exophiala, a dematiacerous mold. 18S rRNA gene sequencing provided results 12 days earlier than phenotypic identification and revealed 15 base difference (0.9%) between the isolate and Exophiala sp. strain GHP 1205 (GenBank Accession no. AJ232954), indicating that the isolate most closely resembles a strain of Exophiala species. The patient responded to 4 weeks of intravenous amphotericin B therapy. Early identification of the fungus was important for the choice of anti-fungal regimen. As opportunistic fungal infections in immunocompromised patients are globally emerging problems, the development of molecular techniques for fungal identification is crucial for early diagnosis and appropriate treatment.
Yoshihisa Hashiguchi - One of the best experts on this subject based on the ideXlab platform.
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molecular typing of sand fly species diptera psychodidae phlebotominae from areas endemic for leishmaniasis in ecuador by pcr rflp of 18S Ribosomal RNA gene
Journal of Veterinary Medical Science, 2008Co-Authors: Yoshimi Terayama, Hirotomo Kato, Eduardo A Gomez, Hiroshi Uezato, Manuel Calvopina, Hiroyuki Iwata, Yoshihisa HashiguchiAbstract:Surveillance of the distribution of sand fly species is important for prediction of the risk and expansion of Leishmania infection in endemic and surrounding areas. In the present study, a simple and reliable method of typing New World Lutzomyia species circulating in endemic areas in Ecuador was established by using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique. PCR-RFLP of 18S Ribosomal RNA (rRNA) genes with the restriction enzyme AfaI and subsequently HinfI successfully identified seven sand fly species in nine endemic areas in Ecuador. Although intraspecific genetic-diversity affecting the RFLP-patterns was detected in a species, the patterns were species specific. The method promises to be a powerful tool for the classification of New World Lutzomyia species.
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molecular typing of sand fly species diptera psychodidae phlebotominae from areas endemic for leishmaniasis in ecuador by pcr rflp of 18S Ribosomal RNA gene
Journal of Veterinary Medical Science, 2008Co-Authors: Yoshimi Terayama, Hirotomo Kato, Eduardo A Gomez, Hiroshi Uezato, Manuel Calvopina, Hiroyuki Iwata, Yoshihisa HashiguchiAbstract:Surveillance of the distribution of sand fly species is important for prediction of the risk and expansion of Leishmania infection in endemic and surrounding areas. In the present study, a simple and reliable method of typing New World Lutzomyia species circulating in endemic areas in Ecuador was established by using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique. PCR-RFLP of 18S Ribosomal RNA (rRNA) genes with the restriction enzyme AfaI and subsequently HinfI successfully identified seven sand fly species in nine endemic areas in Ecuador. Although intraspecific genetic-diversity affecting the RFLP-patterns was detected in a species, the patterns were species specific. The method promises to be a powerful tool for the classification of New World Lutzomyia species.
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the identification of sandfly species from an area of argentina with endemic leishmaniasis by the pcr based analysis of the gene coding for 18S Ribosomal RNA
Annals of Tropical Medicine and Parasitology, 2007Co-Authors: Paola A Barroso, Hirotomo Kato, Jorge D Marco, R Tarama, P Rueda, Silvana P Cajal, Miguel A Basombrio, Masataka Korenaga, Nestor J Taranto, Yoshihisa HashiguchiAbstract:AbstractThe area around Rio Blanco, in the Oran department in the north of the Argentinian province of Salta, is endemic for American tegumentary leishmaniasis. In an attempt to facilitate the identification of the Lutzomyia species in this area, sequences of the gene coding for the 18S Ribosomal RNA (rRNA) of sandflies caught in a Shannon trap were explored, by a combination of PCR and analysis of restriction-fragment-length polymorphism (RFLP). The products from the PCR, which employed two primers developed specifically for this study (Lu.18S 1S and Lu.18S AR), were cloned into a commercial vector (pGEM-T Easy) so that their nucleotide sequences could be investigated. In the RFLP analysis, the products of single and double digestion with the AfaI and HapII restriction enzymes were separated by electrophoresis in 3% or 4% agarose. Taken together with the results of a morphological investigation of the flies, the resultant DNA fragment patterns were sufficient to identify most of the sandflies caught as L...
Leismann Jessica - One of the best experts on this subject based on the ideXlab platform.
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The 18S Ribosomal RNA m6A methyltransferase Mettl5 is required for normal walking behavior in Drosophila
'EMBO', 2020Co-Authors: Leismann Jessica, Spagnuolo Mariangela, Pradhan Mihika, Wacheul Ludivine, Vu, Minh Anh, Musheev Michael, Mier Pablo, Andrade-navarro, Miguel Angel, Graille Marc, Niehrs ChristofAbstract:RNA modifications have recently emerged as an important layer of gene regulation. N6-methyladenosine (m6A) is the most prominent modification on eukaryotic messenger RNA and has also been found on noncoding RNA, including Ribosomal and small nuclear RNA. Recently, several m6A methyltransferases were identified, uncovering the specificity of m6A deposition by structurally distinct enzymes. In order to discover additional m6A enzymes, we performed an RNAi screen to deplete annotated orthologs of human methyltransferase-like proteins (METTLs) in Drosophila cells and identified CG9666, the ortholog of human METTL5. We show that CG9666 is required for specific deposition of m6A on 18S Ribosomal RNA via direct interaction with the Drosophila ortholog of human TRMT112, CG12975. Depletion of CG9666 yields a subsequent loss of the 18S rRNA m6A modification, which lies in the vicinity of the ribosome decoding center; however, this does not compromise rRNA maturation. Instead, a loss of CG9666-mediated m6A impacts fly behavior, providing an underlying molecular mechanism for the reported human phenotype in intellectual disability. Thus, our work expands the repertoire of m6A methyltransferases, demonstrates the specialization of these enzymes, and further addresses the significance of Ribosomal RNA modifications in gene expression and animal behavior.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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The 18S Ribosomal RNA m 6 A methyltransferase Mettl5 is required for normal walking behavior in Drosophila
'EMBO', 2020Co-Authors: Leismann Jessica, Spagnuolo Mariangela, Pradhan Mihika, Wacheul Ludivine, Musheev Michael, Mier Pablo, Graille Marc, Anh Vu Minh, Andrade-navarro, Miguel A., Niehrs ChristofAbstract:InteRNAtional audienceRNA modifications have recently emerged as an important layer of gene regulation. N6-methyladenosine (m6 A) is the most prominent modification on eukaryotic messenger RNA and has also been found on noncoding RNA, including Ribosomal and small nuclear RNA. Recently, several m6 A methyltransferases were identified, uncovering the specificity of m6 A deposition by structurally distinct enzymes. In order to discover additional m6 A enzymes, we performed an RNAi screen to deplete annotated orthologs of human methyltransferase-like proteins (METTLs) in Drosophila cells and identified CG9666, the ortholog of human METTL5. We show that CG9666 is required for specific deposition of m6 A on 18S Ribosomal RNA via direct interaction with the Drosophila ortholog of human TRMT112, CG12975. Depletion of CG9666 yields a subsequent loss of the 18S rRNA m6 A modification, which lies in the vicinity of the ribosome decoding center; however, this does not compromise rRNA maturation. Instead, a loss of CG9666-mediated m6 A impacts fly behavior, providing an underlying molecular mechanism for the reported human phenotype in intellectual disability. Thus, our work expands the repertoire of m6 A methyltransferases, demonstrates the specialization of these enzymes, and further addresses the significance of Ribosomal RNA modifications in gene expression and animal behavior
