The Experts below are selected from a list of 14304 Experts worldwide ranked by ideXlab platform
David C Baulcombe - One of the best experts on this subject based on the ideXlab platform.
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endogenous mirna in the green alga chlamydomonas regulates gene expression through cds targeting
Nature plants, 2017Co-Authors: Betty Y W Chung, Michael J Deery, Arnoud J Groen, Julie Howard, David C BaulcombeAbstract:MicroRNAs (miRNAs) are 21-24-nucleotide RNAs present in many eukaryotes that regulate gene expression as part of the RNA-induced silencing complex. The sequence identity of the miRNA provides the specificity to guide the silencing effector Argonaute (AGO) protein to target mRNAs via a base-Pairing Process 1 . The AGO complex promotes translation repression and/or accelerated decay of this target mRNA 2 . There is overwhelming evidence both in vivo and in vitro that translation repression plays a major role 3-7 . However, there has been controversy about which of these three mechanisms is more significant in vivo, especially when effects of miRNA on endogenous genes cannot be faithfully represented by reporter systems in which, at least in metazoans, the observed repression vastly exceeds that typically observed for endogenous mRNAs 8,9 . Here, we provide a comprehensive global analysis of the evolutionarily distant unicellular green alga Chlamydomonas reinhardtii to quantify the effects of miRNA on protein synthesis and RNA abundance. We show that, similar to metazoan steady-state systems, endogenous miRNAs in Chlamydomonas can regulate gene expression both by destabilization of the mRNA and by translational repression. However, unlike metazoan miRNA where target site utilization localizes mainly to 3' UTRs, in Chlamydomonas utilized target sites lie predominantly within coding regions. These results demonstrate the evolutionarily conserved mode of action for miRNAs, but details of the mechanism diverge between the plant and metazoan kingdoms.
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endogenous mirna in the green alga chlamydomonas regulates gene expression through cds targeting
Nature plants, 2017Co-Authors: Betty Y W Chung, Michael J Deery, Arnoud J Groen, Julie Howard, David C BaulcombeAbstract:MicroRNAs (miRNAs) are 21–24-nucleotide RNAs present in many eukaryotes that regulate gene expression as part of the RNA-induced silencing complex. The sequence identity of the miRNA provides the specificity to guide the silencing effector Argonaute (AGO) protein to target mRNAs via a base-Pairing Process 1 . The AGO complex promotes translation repression and/or accelerated decay of this target mRNA 2 . There is overwhelming evidence both in vivo and in vitro that translation repression plays a major role 3–7 . However, there has been controversy about which of these three mechanisms is more significant in vivo, especially when effects of miRNA on endogenous genes cannot be faithfully represented by reporter systems in which, at least in metazoans, the observed repression vastly exceeds that typically observed for endogenous mRNAs 8,9 . Here, we provide a comprehensive global analysis of the evolutionarily distant unicellular green alga Chlamydomonas reinhardtii to quantify the effects of miRNA on protein synthesis and RNA abundance. We show that, similar to metazoan steady-state systems, endogenous miRNAs in Chlamydomonas can regulate gene expression both by destabilization of the mRNA and by translational repression. However, unlike metazoan miRNA where target site utilization localizes mainly to 3′ UTRs, in Chlamydomonas utilized target sites lie predominantly within coding regions. These results demonstrate the evolutionarily conserved mode of action for miRNAs, but details of the mechanism diverge between the plant and metazoan kingdoms. MicroRNAs regulate gene expression as part of the RNA-induced silencing complex. An analysis of miRNA in Chlamydomonas reinhardtiishows that algal miRNAs target sites predominantly within coding regions to destabilize mRNA and repress translation.
Betty Y W Chung - One of the best experts on this subject based on the ideXlab platform.
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endogenous mirna in the green alga chlamydomonas regulates gene expression through cds targeting
Nature plants, 2017Co-Authors: Betty Y W Chung, Michael J Deery, Arnoud J Groen, Julie Howard, David C BaulcombeAbstract:MicroRNAs (miRNAs) are 21-24-nucleotide RNAs present in many eukaryotes that regulate gene expression as part of the RNA-induced silencing complex. The sequence identity of the miRNA provides the specificity to guide the silencing effector Argonaute (AGO) protein to target mRNAs via a base-Pairing Process 1 . The AGO complex promotes translation repression and/or accelerated decay of this target mRNA 2 . There is overwhelming evidence both in vivo and in vitro that translation repression plays a major role 3-7 . However, there has been controversy about which of these three mechanisms is more significant in vivo, especially when effects of miRNA on endogenous genes cannot be faithfully represented by reporter systems in which, at least in metazoans, the observed repression vastly exceeds that typically observed for endogenous mRNAs 8,9 . Here, we provide a comprehensive global analysis of the evolutionarily distant unicellular green alga Chlamydomonas reinhardtii to quantify the effects of miRNA on protein synthesis and RNA abundance. We show that, similar to metazoan steady-state systems, endogenous miRNAs in Chlamydomonas can regulate gene expression both by destabilization of the mRNA and by translational repression. However, unlike metazoan miRNA where target site utilization localizes mainly to 3' UTRs, in Chlamydomonas utilized target sites lie predominantly within coding regions. These results demonstrate the evolutionarily conserved mode of action for miRNAs, but details of the mechanism diverge between the plant and metazoan kingdoms.
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endogenous mirna in the green alga chlamydomonas regulates gene expression through cds targeting
Nature plants, 2017Co-Authors: Betty Y W Chung, Michael J Deery, Arnoud J Groen, Julie Howard, David C BaulcombeAbstract:MicroRNAs (miRNAs) are 21–24-nucleotide RNAs present in many eukaryotes that regulate gene expression as part of the RNA-induced silencing complex. The sequence identity of the miRNA provides the specificity to guide the silencing effector Argonaute (AGO) protein to target mRNAs via a base-Pairing Process 1 . The AGO complex promotes translation repression and/or accelerated decay of this target mRNA 2 . There is overwhelming evidence both in vivo and in vitro that translation repression plays a major role 3–7 . However, there has been controversy about which of these three mechanisms is more significant in vivo, especially when effects of miRNA on endogenous genes cannot be faithfully represented by reporter systems in which, at least in metazoans, the observed repression vastly exceeds that typically observed for endogenous mRNAs 8,9 . Here, we provide a comprehensive global analysis of the evolutionarily distant unicellular green alga Chlamydomonas reinhardtii to quantify the effects of miRNA on protein synthesis and RNA abundance. We show that, similar to metazoan steady-state systems, endogenous miRNAs in Chlamydomonas can regulate gene expression both by destabilization of the mRNA and by translational repression. However, unlike metazoan miRNA where target site utilization localizes mainly to 3′ UTRs, in Chlamydomonas utilized target sites lie predominantly within coding regions. These results demonstrate the evolutionarily conserved mode of action for miRNAs, but details of the mechanism diverge between the plant and metazoan kingdoms. MicroRNAs regulate gene expression as part of the RNA-induced silencing complex. An analysis of miRNA in Chlamydomonas reinhardtiishows that algal miRNAs target sites predominantly within coding regions to destabilize mRNA and repress translation.
Trude Schwarzacher - One of the best experts on this subject based on the ideXlab platform.
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chromosome nuclear envelope tethering a Process that orchestrates homologue Pairing during plant meiosis
Journal of Cell Science, 2020Co-Authors: Adel Sepsi, Trude SchwarzacherAbstract:ABSTRACT During prophase I of meiosis, homologous chromosomes pair, synapse and exchange their genetic material through reciprocal homologous recombination, a phenomenon essential for faithful chromosome segregation. Partial sequence identity between non-homologous and heterologous chromosomes can also lead to recombination (ectopic recombination), a highly deleterious Process that rapidly compromises genome integrity. To avoid ectopic exchange, homology recognition must be extended from the narrow position of a crossover-competent double-strand break to the entire chromosome. Here, we review advances on chromosome behaviour during meiotic prophase I in higher plants, by integrating centromere- and telomere dynamics driven by cytoskeletal motor proteins, into the Processes of homologue Pairing, synapsis and recombination. Centromere–centromere associations and the gathering of telomeres at the onset of meiosis at opposite nuclear poles create a spatially organised and restricted nuclear state in which homologous DNA interactions are favoured but ectopic interactions also occur. The release and dispersion of centromeres from the nuclear periphery increases the motility of chromosome arms, allowing meiosis-specific movements that disrupt ectopic interactions. Subsequent expansion of interstitial synapsis from numerous homologous interactions further corrects ectopic interactions. Movement and organisation of chromosomes, thus, evolved to facilitate the Pairing Process, and can be modulated by distinct stages of chromatin associations at the nuclear envelope and their collective release.
Montserrat Garcia - One of the best experts on this subject based on the ideXlab platform.
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human fetal ovarian culture permits meiotic progression and chromosome Pairing Process
Human Reproduction, 2006Co-Authors: Ignasi Roig, Pedro Robles, Joseè Egozcue, R Garcia, R Cortvrindt, Johan Smitz, Montserrat GarciaAbstract:BACKGROUND The female meiotic Process seems to be crucial for aneuploidy in humans. The first stages of mammalian female meiosis take place during the fetal period. Therefore, only little is known about female meiosis. The goal of this study was to develop a culture technique that permits human oocytes to progress through meiotic prophase, to provide a system to study human female meiosis. METHOD Fetal ovaries from four cases were cultured up to 35 days in alpha-minimal essential medium, 2% human serum albumin, 5 microg/ml insulin, 5 microg/ml transferrin, 5 ng/ml selenium and 100 IU/ml penicillin-100 microg/ml streptomycin. RESULTS AND CONCLUSIONS Although ovarian response to culture conditions varied, human oocytes survived in vitro up to 5 weeks. In three cases, we observed significant variation in stages of meiosis among the cultures. The homologous chromosome Pairing Process was studied for the first time in cultured oocytes, and the results suggested that the Pairing Process was completed following the same features described previously for euploid oocytes, as followed by the chromosome-13 Pairing Process and synaptonemal complex formation. Although a higher proportion of degenerated oocytes were observed as culture time increased, we also observed oogonial entrance to meiotic prophase.
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Evolution of the meiotic prophase and of the chromosome Pairing Process during human fetal ovarian development
Human Reproduction, 2005Co-Authors: Ignasi Roig, Pedro Robles, Joseè Egozcue, Lluis Cabero, S. Barambio, M. Martin, R Garcia, Montserrat GarciaAbstract:BACKGROUND: Studies on human oocytes in prophase I are limited due to the difficulty in obtaining the sample. However, a complete study of meiotic prophase evolution and the homologue Pairing Process is necessary to try to understand the implication of oogenesis in the origin of human aneuploidy. METHODS: A complete analysis of meiotic prophase progression comprising the long developmental time period during which meiotic prophase takes place, based on the analysis of a total of 8603 oocytes in prophase I from 15 different cases is presented. The Pairing Process of chromosomes 13 and 18 is also described. RESULTS: The findings significantly relate for the first time the evolution of meiotic prophase to fetal development. Although for both chromosomes 13 and 18 a high Pairing efficiency is found, Pairing failure at the pachytene stage has been observed in 0.1% of oocytes. However, errors at the diplotene stage are substantially increased, suggesting that complete, premature disjunction of the homologues commonly occurs. Moreover, pre-meiotic errors are also described. CONCLUSIONS: Our findings show that homologous chromosomes pair very efficiently, but the high frequency of complete, premature homologue separation found at diplotene suggests that mechanisms other than the Pairing Process could be more likely to lead to the high aneuploidy rate observed in human oocytes.
Julie Howard - One of the best experts on this subject based on the ideXlab platform.
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endogenous mirna in the green alga chlamydomonas regulates gene expression through cds targeting
Nature plants, 2017Co-Authors: Betty Y W Chung, Michael J Deery, Arnoud J Groen, Julie Howard, David C BaulcombeAbstract:MicroRNAs (miRNAs) are 21-24-nucleotide RNAs present in many eukaryotes that regulate gene expression as part of the RNA-induced silencing complex. The sequence identity of the miRNA provides the specificity to guide the silencing effector Argonaute (AGO) protein to target mRNAs via a base-Pairing Process 1 . The AGO complex promotes translation repression and/or accelerated decay of this target mRNA 2 . There is overwhelming evidence both in vivo and in vitro that translation repression plays a major role 3-7 . However, there has been controversy about which of these three mechanisms is more significant in vivo, especially when effects of miRNA on endogenous genes cannot be faithfully represented by reporter systems in which, at least in metazoans, the observed repression vastly exceeds that typically observed for endogenous mRNAs 8,9 . Here, we provide a comprehensive global analysis of the evolutionarily distant unicellular green alga Chlamydomonas reinhardtii to quantify the effects of miRNA on protein synthesis and RNA abundance. We show that, similar to metazoan steady-state systems, endogenous miRNAs in Chlamydomonas can regulate gene expression both by destabilization of the mRNA and by translational repression. However, unlike metazoan miRNA where target site utilization localizes mainly to 3' UTRs, in Chlamydomonas utilized target sites lie predominantly within coding regions. These results demonstrate the evolutionarily conserved mode of action for miRNAs, but details of the mechanism diverge between the plant and metazoan kingdoms.
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endogenous mirna in the green alga chlamydomonas regulates gene expression through cds targeting
Nature plants, 2017Co-Authors: Betty Y W Chung, Michael J Deery, Arnoud J Groen, Julie Howard, David C BaulcombeAbstract:MicroRNAs (miRNAs) are 21–24-nucleotide RNAs present in many eukaryotes that regulate gene expression as part of the RNA-induced silencing complex. The sequence identity of the miRNA provides the specificity to guide the silencing effector Argonaute (AGO) protein to target mRNAs via a base-Pairing Process 1 . The AGO complex promotes translation repression and/or accelerated decay of this target mRNA 2 . There is overwhelming evidence both in vivo and in vitro that translation repression plays a major role 3–7 . However, there has been controversy about which of these three mechanisms is more significant in vivo, especially when effects of miRNA on endogenous genes cannot be faithfully represented by reporter systems in which, at least in metazoans, the observed repression vastly exceeds that typically observed for endogenous mRNAs 8,9 . Here, we provide a comprehensive global analysis of the evolutionarily distant unicellular green alga Chlamydomonas reinhardtii to quantify the effects of miRNA on protein synthesis and RNA abundance. We show that, similar to metazoan steady-state systems, endogenous miRNAs in Chlamydomonas can regulate gene expression both by destabilization of the mRNA and by translational repression. However, unlike metazoan miRNA where target site utilization localizes mainly to 3′ UTRs, in Chlamydomonas utilized target sites lie predominantly within coding regions. These results demonstrate the evolutionarily conserved mode of action for miRNAs, but details of the mechanism diverge between the plant and metazoan kingdoms. MicroRNAs regulate gene expression as part of the RNA-induced silencing complex. An analysis of miRNA in Chlamydomonas reinhardtiishows that algal miRNAs target sites predominantly within coding regions to destabilize mRNA and repress translation.
