The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Elitza Deltcheva - One of the best experts on this subject based on the ideXlab platform.
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crispr rna maturation by trans encoded small rna and Host Factor rnase iii
Nature, 2011Co-Authors: Elitza Deltcheva, Cynthia M Sharma, Karine Gonzales, Zaid Ahmed Pirzada, Maria R Eckert, Krzysztof Chylinski, Yanjie Chao, Jorg Vogel, Emmanuelle CharpentierAbstract:CRISPR/Cas systems constitute a widespread class of immunity systems that protect bacteria and archaea against phages and plasmids, and commonly use repeat/spacer-derived short crRNAs to silence foreign nucleic acids in a sequence-specific manner. Although the maturation of crRNAs represents a key event in CRISPR activation, the responsible endoribonucleases (CasE, Cas6, Csy4) are missing in many CRISPR/Cas subtypes. Here, differential RNA sequencing of the human pathogen Streptococcus pyogenes uncovered tracrRNA, a trans-encoded small RNA with 24-nucleotide complementarity to the repeat regions of crRNA precursor transcripts. We show that tracrRNA directs the maturation of crRNAs by the activities of the widely conserved endogenous RNase III and the CRISPR-associated Csn1 protein; all these components are essential to protect S. pyogenes against prophage-derived DNA. Our study reveals a novel pathway of small guide RNA maturation and the first example of a Host Factor (RNase III) required for bacterial RNA-mediated immunity against invaders.
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crispr rna maturation by trans encoded small rna and Host Factor rnase iii
Nature, 2011Co-Authors: Elitza Deltcheva, Cynthia M Sharma, Karine Gonzales, Zaid Ahmed Pirzada, Maria R Eckert, Krzysztof Chylinski, Yanjie Chao, Jorg VogelAbstract:CRISPR is a microbial RNA-based immune system protecting against viral and plasmid invasions. The CRISPR system is thought to rely on cleavage of a precursor RNA transcript by Cas endonucleases, but not all species with CRISPR-type immunity encode Cas proteins. A new study reveals an alternative pathway for CRISPR activation in the human pathogen Streptococcus pyogenes, in which a trans-encoded small RNA directs processing of precursor RNA into crRNAs through endogenous RNase III and the CRISPR-associated Csn1 protein.
Krzysztof Chylinski - One of the best experts on this subject based on the ideXlab platform.
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crispr rna maturation by trans encoded small rna and Host Factor rnase iii
Nature, 2011Co-Authors: Elitza Deltcheva, Cynthia M Sharma, Karine Gonzales, Zaid Ahmed Pirzada, Maria R Eckert, Krzysztof Chylinski, Yanjie Chao, Jorg Vogel, Emmanuelle CharpentierAbstract:CRISPR/Cas systems constitute a widespread class of immunity systems that protect bacteria and archaea against phages and plasmids, and commonly use repeat/spacer-derived short crRNAs to silence foreign nucleic acids in a sequence-specific manner. Although the maturation of crRNAs represents a key event in CRISPR activation, the responsible endoribonucleases (CasE, Cas6, Csy4) are missing in many CRISPR/Cas subtypes. Here, differential RNA sequencing of the human pathogen Streptococcus pyogenes uncovered tracrRNA, a trans-encoded small RNA with 24-nucleotide complementarity to the repeat regions of crRNA precursor transcripts. We show that tracrRNA directs the maturation of crRNAs by the activities of the widely conserved endogenous RNase III and the CRISPR-associated Csn1 protein; all these components are essential to protect S. pyogenes against prophage-derived DNA. Our study reveals a novel pathway of small guide RNA maturation and the first example of a Host Factor (RNase III) required for bacterial RNA-mediated immunity against invaders.
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crispr rna maturation by trans encoded small rna and Host Factor rnase iii
Nature, 2011Co-Authors: Elitza Deltcheva, Cynthia M Sharma, Karine Gonzales, Zaid Ahmed Pirzada, Maria R Eckert, Krzysztof Chylinski, Yanjie Chao, Jorg VogelAbstract:CRISPR is a microbial RNA-based immune system protecting against viral and plasmid invasions. The CRISPR system is thought to rely on cleavage of a precursor RNA transcript by Cas endonucleases, but not all species with CRISPR-type immunity encode Cas proteins. A new study reveals an alternative pathway for CRISPR activation in the human pathogen Streptococcus pyogenes, in which a trans-encoded small RNA directs processing of precursor RNA into crRNAs through endogenous RNase III and the CRISPR-associated Csn1 protein.
Brett D Lindenbach - One of the best experts on this subject based on the ideXlab platform.
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a sensitive yellow fever virus entry reporter identifies valosin containing protein vcp p97 as an essential Host Factor for flavivirus uncoating
Mbio, 2020Co-Authors: Harish N Ramanathan, Shuo Zhang, Florian Douam, Jinhong Chang, Priscilla L Yang, John W Schoggins, Alexander Ploss, Brett D LindenbachAbstract:ABSTRACT While the basic mechanisms of flavivirus entry and fusion are understood, little is known about the postfusion events that precede RNA replication, such as nucleocapsid disassembly. We describe here a sensitive, conditionally replication-defective yellow fever virus (YFV) entry reporter, YFVΔSK/Nluc, to quantitively monitor the translation of incoming, virus particle-delivered genomes. We validated that YFVΔSK/Nluc gene expression can be neutralized by YFV-specific antisera and requires known flavivirus entry pathways and cellular Factors, including clathrin- and dynamin-mediated endocytosis, endosomal acidification, YFV E glycoprotein-mediated fusion, and cellular LY6E and RPLP1 expression. The initial round of YFV translation was shown to require cellular ubiquitylation, consistent with recent findings that dengue virus capsid protein must be ubiquitylated in order for nucleocapsid uncoating to occur. Importantly, translation of incoming YFV genomes also required valosin-containing protein (VCP)/p97, a cellular ATPase that unfolds and extracts ubiquitylated client proteins from large complexes. RNA transfection and washout experiments showed that VCP/p97 functions at a postfusion, pretranslation step in YFV entry. Finally, VCP/p97 activity was required by other flaviviruses in mammalian cells and by YFV in mosquito cells. Together, these data support a critical role for VCP/p97 in the disassembly of incoming flavivirus nucleocapsids during a postfusion step in virus entry. IMPORTANCE Flaviviruses are an important group of RNA viruses that cause significant human disease. The mechanisms by which flavivirus nucleocapsids are disassembled during virus entry remain unclear. Here, we used a yellow fever virus entry reporter, which expresses a sensitive reporter enzyme but does not replicate, to show that nucleocapsid disassembly requires the cellular protein-disaggregating enzyme valosin-containing protein, also known as p97.
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a sensitive yellow fever virus entry reporter identifies valosin containing protein vcp p97 as an essential Host Factor for flavivirus uncoating
bioRxiv, 2019Co-Authors: Harish N Ramanathan, Shuo Zhang, Florian Douam, Jinhong Chang, Priscilla L Yang, Alexander Ploss, Brett D LindenbachAbstract:While the basic mechanisms of flavivirus entry and fusion are understood, little is known about the post-fusion events that precede RNA replication, such as nucleocapsid disassembly. We describe here a sensitive, conditionally replication-defective yellow fever virus (YFV) entry reporter, YFV{Delta}SK/Nluc, to quantitively monitor the translation of incoming, virus particle-delivered genomes. We validated that YFV{Delta}SK/Nluc gene expression can be neutralized by YFV-specific antisera and requires known flavivirus entry pathways, including clathrin- and dynamin-mediated endocytosis, endosomal acidification, YFV E glycoprotein-mediated fusion, and cellular LY6E expression; however, as expected, gene expression from the defective reporter virus was insensitive to a small molecule inhibitor of YFV RNA replication. YFV{Delta}SK/Nluc gene expression was also shown to require cellular ubiquitylation, consistent with recent findings that dengue virus capsid protein must be ubiquitylated in order for nucleocapsid uncoating to occur, as well as valosin-containing protein (VCP)/p97, a cellular ATPase that unfolds and extracts ubiquitylated client proteins from large macromolecular complexes. RNA transfection and washout experiments showed that VCP/p97 functions at a post-fusion, pre-translation step in YFV entry. Together, these data support a critical role for VCP/p97 in the disassembly of incoming flavivirus nucleocapsids during a post-fusion step in virus entry.nnIMPORTANCEFlaviviruses are an important group of RNA viruses that cause significant human disease. The mechanisms by which flavivirus nucleocapsids are disassembled during virus entry remain unclear. Here we show that the yellow fever virus nucleocapsid disassembly requires the cellular protein-disaggregating enzyme valosin-containing protein, also known as p97.
James M Cunningham - One of the best experts on this subject based on the ideXlab platform.
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critical role for cholesterol in lassa fever virus entry identified by a novel small molecule inhibitor targeting the viral receptor lamp1
PLOS Pathogens, 2018Co-Authors: May Kwangmei Wang, Anna N Honko, Huanying Zhou, Julie Dyall, Lisa E Hensley, Ashley K Gartin, James M CunninghamAbstract:Lassa fever virus (LASV) is endemic in West Africa and causes severe hemorrhagic fever and sensorineural hearing loss. We identified a small molecule inhibitor of LASV and used it to analyze the mechanism of entry. Using a photo-reactive analog that retains antiviral activity as a probe, we identified the inhibitor target as lysosome-associated membrane protein 1 (LAMP1), a Host Factor that binds to the LASV glycoprotein (GP) during infection. We found that LAMP1 binding to LASV GP is cholesterol-dependent, and that the inhibitor blocks infection by competing with cholesterol in LAMP1. Mutational analysis of a docking-based model identified a putative inhibitor binding site in the cholesterol-binding pocket within the LAMP1 domain that binds GP. These findings identify a critical role for cholesterol in LASV entry and a potential target for therapeutic intervention.
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development of locked nucleic acid antisense oligonucleotides targeting ebola viral proteins and Host Factor niemann pick c1
Nucleic Acid Therapeutics, 2018Co-Authors: Jessica Chery, James M Cunningham, Andreas Petri, Alexandre Wagschal, Shobha Vasudevan, Sakari Kauppinen, Anders M NaarAbstract:The Ebola virus is a zoonotic pathogen that can cause severe hemorrhagic fever in humans, with up to 90% lethality. The deadly 2014 Ebola outbreak quickly made an unprecedented impact on human live...
Jorg Vogel - One of the best experts on this subject based on the ideXlab platform.
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crispr rna maturation by trans encoded small rna and Host Factor rnase iii
Nature, 2011Co-Authors: Elitza Deltcheva, Cynthia M Sharma, Karine Gonzales, Zaid Ahmed Pirzada, Maria R Eckert, Krzysztof Chylinski, Yanjie Chao, Jorg Vogel, Emmanuelle CharpentierAbstract:CRISPR/Cas systems constitute a widespread class of immunity systems that protect bacteria and archaea against phages and plasmids, and commonly use repeat/spacer-derived short crRNAs to silence foreign nucleic acids in a sequence-specific manner. Although the maturation of crRNAs represents a key event in CRISPR activation, the responsible endoribonucleases (CasE, Cas6, Csy4) are missing in many CRISPR/Cas subtypes. Here, differential RNA sequencing of the human pathogen Streptococcus pyogenes uncovered tracrRNA, a trans-encoded small RNA with 24-nucleotide complementarity to the repeat regions of crRNA precursor transcripts. We show that tracrRNA directs the maturation of crRNAs by the activities of the widely conserved endogenous RNase III and the CRISPR-associated Csn1 protein; all these components are essential to protect S. pyogenes against prophage-derived DNA. Our study reveals a novel pathway of small guide RNA maturation and the first example of a Host Factor (RNase III) required for bacterial RNA-mediated immunity against invaders.
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crispr rna maturation by trans encoded small rna and Host Factor rnase iii
Nature, 2011Co-Authors: Elitza Deltcheva, Cynthia M Sharma, Karine Gonzales, Zaid Ahmed Pirzada, Maria R Eckert, Krzysztof Chylinski, Yanjie Chao, Jorg VogelAbstract:CRISPR is a microbial RNA-based immune system protecting against viral and plasmid invasions. The CRISPR system is thought to rely on cleavage of a precursor RNA transcript by Cas endonucleases, but not all species with CRISPR-type immunity encode Cas proteins. A new study reveals an alternative pathway for CRISPR activation in the human pathogen Streptococcus pyogenes, in which a trans-encoded small RNA directs processing of precursor RNA into crRNAs through endogenous RNase III and the CRISPR-associated Csn1 protein.