The Experts below are selected from a list of 15324 Experts worldwide ranked by ideXlab platform
Stephen M. Cohen - One of the best experts on this subject based on the ideXlab platform.
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control of drosophila type i and type ii central brain neuroblast proliferation by Bantam microrna
Development, 2015Co-Authors: Ruifen Weng, Stephen M. CohenAbstract:Post-transcriptional regulation of stem cell self-renewal by microRNAs is emerging as an important mechanism controlling tissue homeostasis. Here, we provide evidence that Bantam microRNA controls neuroblast number and proliferation in the Drosophila central brain. Bantam also supports proliferation of transit-amplifying intermediate neural progenitor cells in type II neuroblast lineages. The stem cell factors brat and prospero are identified as Bantam targets acting on different aspects of these processes. Thus, Bantam appears to act in multiple regulatory steps in the maintenance and proliferation of neuroblasts and their progeny to regulate growth of the central brain.
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mutual repression by Bantam mirna and capicua links the egfr mapk and hippo pathways in growth control
Current Biology, 2012Co-Authors: Héctor Herranz, Xin Hong, Stephen M. CohenAbstract:Summary Background The epidermal growth factor receptor (EGFR) and Hippo signaling pathways control cell proliferation and apoptosis to promote tissue growth during development. Misregulation of these pathways is implicated in cancer. Our understanding of the mechanisms that integrate the activity of these pathways remains fragmentary. This study identifies Bantam microRNA as a common target of these pathways and suggests a mechanistic link between them. Results The EGFR pathway acts through Bantam to control tissue growth. Bantam expression is regulated by the EGFR pathway, acting via repression of the transcriptional repressor Capicua. Thus EGFR signaling induces Bantam expression by alleviating the effects of a repressor. Bantam in turn acts in a negative feedback loop to limit Capicua expression. Conclusions Bantam appears to be a transcriptional target of both the EGFR and Hippo growth control pathways. Feedback regulation by Bantam on Capicua provides a means to link signal propagation by the EGFR pathway to activity of the Hippo pathway and may play an important role in integration of these two pathways in growth control.
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Mutual Repression by Bantam miRNA and Capicua Links the EGFR/MAPK and Hippo Pathways in Growth Control
Current biology : CB, 2012Co-Authors: Héctor Herranz, Xin Hong, Stephen M. CohenAbstract:Summary Background The epidermal growth factor receptor (EGFR) and Hippo signaling pathways control cell proliferation and apoptosis to promote tissue growth during development. Misregulation of these pathways is implicated in cancer. Our understanding of the mechanisms that integrate the activity of these pathways remains fragmentary. This study identifies Bantam microRNA as a common target of these pathways and suggests a mechanistic link between them. Results The EGFR pathway acts through Bantam to control tissue growth. Bantam expression is regulated by the EGFR pathway, acting via repression of the transcriptional repressor Capicua. Thus EGFR signaling induces Bantam expression by alleviating the effects of a repressor. Bantam in turn acts in a negative feedback loop to limit Capicua expression. Conclusions Bantam appears to be a transcriptional target of both the EGFR and Hippo growth control pathways. Feedback regulation by Bantam on Capicua provides a means to link signal propagation by the EGFR pathway to activity of the Hippo pathway and may play an important role in integration of these two pathways in growth control.
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Notch-mediated repression of Bantam miRNA contributes to boundary formation in the Drosophila wing
Development (Cambridge England), 2011Co-Authors: Isabelle Becam, Stephen M. Cohen, Xin Hong, Neus Rafel, Marco MilanAbstract:Subdivision of proliferating tissues into adjacent compartments that do not mix plays a key role in animal development. The Actin cytoskeleton has recently been shown to mediate cell sorting at compartment boundaries, and reduced cell proliferation in boundary cells has been proposed as a way of stabilizing compartment boundaries. Cell interactions mediated by the receptor Notch have been implicated in the specification of compartment boundaries in vertebrates and in Drosophila, but the molecular effectors remain largely unidentified. Here, we present evidence that Notch mediates boundary formation in the Drosophila wing in part through repression of Bantam miRNA. Bantam induces cell proliferation and we have identified the Actin regulator Enabled as a new target of Bantam. Increased levels of Enabled and reduced proliferation rates contribute to the maintenance of the dorsal-ventral affinity boundary. The activity of Notch also defines, through the homeobox-containing gene cut, a distinct population of boundary cells at the dorsal-ventral (DV) interface that helps to segregate boundary from non-boundary cells and contributes to the maintenance of the DV affinity boundary.
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The Hippo Pathway Regulates the Bantam microRNA to Control Cell Proliferation and Apoptosis in Drosophila
Cell, 2006Co-Authors: Barry J. Thompson, Stephen M. CohenAbstract:The Hippo signaling pathway acts upon the Yorkie transcriptional activator to control tissue growth in Drosophila. Activated Yorkie drives growth by stimulating cell proliferation and inhibiting apoptosis, but how it achieves this is not understood. Yorkie is known to activate Cyclin E (CycE) and the apoptosis inhibitor DIAP1. However, overexpression of these targets is not sufficient to cause tissue overgrowth. Here we show that Yorkie also activates expression of the Bantam microRNA, a known regulator of both proliferation and apoptosis. Bantam overexpression mimics Yorkie activation while loss of Bantam function slows the rate of cell proliferation. Bantam is necessary for Yorkie-induced overproliferation and Bantam overexpression is sufficient to rescue survival and proliferation of yorkie mutant cells. Finally, we show that Bantam levels are regulated during both developmentally programmed proliferation arrest and apoptosis. In summary, the results show that the Hippo pathway regulates expression of Bantam to control tissue growth in Drosophila.
Weiqing Pan - One of the best experts on this subject based on the ideXlab platform.
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identification and characterization of novel micrornas from schistosoma japonicum
PLOS ONE, 2008Co-Authors: Xiangyang Xue, Junjun Sun, Qingfeng Zhang, Zhangxun Wang, Yufu Huang, Weiqing PanAbstract:Background Schistosomiasis japonica remains a major public health problem in China. Its pathogen, Schistosoma japonicum has a complex life cycle and a unique repertoire of genes expressed at different life cycle stages. Exploring schistosome gene regulation will yield the best prospects for new drug targets and vaccine candidates. MicroRNAs (miRNAs) are a highly conserved class of noncoding RNA that control many biological processes by sequence-specific inhibition of gene expression. Although a large number of miRNAs have been identified from plants to mammals, it remains no experimental proof whether schistosome exist miRNAs. Methodology and Results We have identified novel miRNAs from Schistosoma japonicum by cloning and sequencing a small (18–26 nt) RNA cDNA library from the adult worms. Five novel miRNAs were identified from 227 cloned RNA sequences and verified by Northern blot. Alignments of the miRNAs with corresponding family members indicated that four of them belong to a metazoan miRNA family: let-7, miR-71, Bantam and miR-125. The fifth potentially new (non conserved) miRNA appears to belong to a previously undescribed family in the genus Schistosome. The novel miRNAs were designated as sja-let-7, sja-miR-71, sja-Bantam, sja-miR-125 and sja-miR-new1, respectively. Expression of sja-let-7, sja-miR-71 and sja-Bantam were analyzed in six stages of the life cycle, i.e. egg, miracidium, sporocyst, cercaria, schistosomulum, and adult worm, by a modified stem-loop reverse transcribed polymerase chain reaction (RT-PCR) method developed in our laboratory. The expression patterns of these miRNAs were highly stage-specific. In particular, sja-miR-71 and sja-Bantam expression reach their peaks in the cercaria stage and then drop quickly to the nadirs in the schistosomulum stage, following penetration of cercaria into a mammalian host. Conclusions Authentic miRNAs were identified for the first time in S. japonicum, including a new schistosome family member. The different expression patterns of the novel miRNAs over the life stages of S. japonicum suggest that they may mediate important roles in Schistosome growth and development.
Xiangyang Xue - One of the best experts on this subject based on the ideXlab platform.
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identification and characterization of novel micrornas from schistosoma japonicum
PLOS ONE, 2008Co-Authors: Xiangyang Xue, Junjun Sun, Qingfeng Zhang, Zhangxun Wang, Yufu Huang, Weiqing PanAbstract:Background Schistosomiasis japonica remains a major public health problem in China. Its pathogen, Schistosoma japonicum has a complex life cycle and a unique repertoire of genes expressed at different life cycle stages. Exploring schistosome gene regulation will yield the best prospects for new drug targets and vaccine candidates. MicroRNAs (miRNAs) are a highly conserved class of noncoding RNA that control many biological processes by sequence-specific inhibition of gene expression. Although a large number of miRNAs have been identified from plants to mammals, it remains no experimental proof whether schistosome exist miRNAs. Methodology and Results We have identified novel miRNAs from Schistosoma japonicum by cloning and sequencing a small (18–26 nt) RNA cDNA library from the adult worms. Five novel miRNAs were identified from 227 cloned RNA sequences and verified by Northern blot. Alignments of the miRNAs with corresponding family members indicated that four of them belong to a metazoan miRNA family: let-7, miR-71, Bantam and miR-125. The fifth potentially new (non conserved) miRNA appears to belong to a previously undescribed family in the genus Schistosome. The novel miRNAs were designated as sja-let-7, sja-miR-71, sja-Bantam, sja-miR-125 and sja-miR-new1, respectively. Expression of sja-let-7, sja-miR-71 and sja-Bantam were analyzed in six stages of the life cycle, i.e. egg, miracidium, sporocyst, cercaria, schistosomulum, and adult worm, by a modified stem-loop reverse transcribed polymerase chain reaction (RT-PCR) method developed in our laboratory. The expression patterns of these miRNAs were highly stage-specific. In particular, sja-miR-71 and sja-Bantam expression reach their peaks in the cercaria stage and then drop quickly to the nadirs in the schistosomulum stage, following penetration of cercaria into a mammalian host. Conclusions Authentic miRNAs were identified for the first time in S. japonicum, including a new schistosome family member. The different expression patterns of the novel miRNAs over the life stages of S. japonicum suggest that they may mediate important roles in Schistosome growth and development.
Carolyn A Emery - One of the best experts on this subject based on the ideXlab platform.
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the effect of the zero tolerance for head contact rule change on the risk of concussions in youth ice hockey players
American Journal of Sports Medicine, 2017Co-Authors: Maciej Krolikowski, Amanda M Black, Luz Palaciosderflingher, Tracy Blake, Kathryn J Schneider, Carolyn A EmeryAbstract:Background:Ice hockey is a popular winter sport in Canada. Concussions account for the greatest proportion of all injuries in youth ice hockey. In 2011, a policy change enforcing “zero tolerance for head contact” was implemented in all leagues in Canada.Purpose:To determine if the risk of game-related concussions and more severe concussions (ie, resulting in >10 days of time loss) and the mechanisms of a concussion differed for Pee Wee class (ages 11-12 years) and Bantam class (ages 13-14 years) players after the 2011 “zero tolerance for head contact” policy change compared with players in similar divisions before the policy change.Study Design:Cohort study; Level of evidence, 3.Methods:The retrospective cohort included Pee Wee (most elite 70%, 2007-2008; n = 891) and Bantam (most elite 30%, 2008-2009; n = 378) players before the rule change and Pee Wee (2011-2012; n = 588) and Bantam (2011-2012; n = 242) players in the same levels of play after the policy change. Suspected concussions were identified by ...
Kathryn J Schneider - One of the best experts on this subject based on the ideXlab platform.
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the effect of the zero tolerance for head contact rule change on the risk of concussions in youth ice hockey players
American Journal of Sports Medicine, 2017Co-Authors: Maciej Krolikowski, Amanda M Black, Luz Palaciosderflingher, Tracy Blake, Kathryn J Schneider, Carolyn A EmeryAbstract:Background:Ice hockey is a popular winter sport in Canada. Concussions account for the greatest proportion of all injuries in youth ice hockey. In 2011, a policy change enforcing “zero tolerance for head contact” was implemented in all leagues in Canada.Purpose:To determine if the risk of game-related concussions and more severe concussions (ie, resulting in >10 days of time loss) and the mechanisms of a concussion differed for Pee Wee class (ages 11-12 years) and Bantam class (ages 13-14 years) players after the 2011 “zero tolerance for head contact” policy change compared with players in similar divisions before the policy change.Study Design:Cohort study; Level of evidence, 3.Methods:The retrospective cohort included Pee Wee (most elite 70%, 2007-2008; n = 891) and Bantam (most elite 30%, 2008-2009; n = 378) players before the rule change and Pee Wee (2011-2012; n = 588) and Bantam (2011-2012; n = 242) players in the same levels of play after the policy change. Suspected concussions were identified by ...
