dna RADIO: Radio host and All About Jazz Contributor Ed Blanco celebrates 13 years of Jazz Café on WDNA 88.9FM By news.allaboutjazz.com Published On :: 2020-04-30T16:45:38+00:00 Jazz radio host and All About Jazz contributor Ed Blanco, in May 2020 celebrates 13 years as producer and host of Jazz Café, an early Sunday morning jazz show on WDNA, 88.9FM in Miami, Florida... Full Article
dna Stock Alert: Applied DNA Sciences Stock Surges 94% In Premarket By www.rttnews.com Published On :: Mon, 04 May 2020 13:16:12 GMT Shares of Applied DNA Sciences Inc. (APDN) are soaring over 94% in pre-market today, after the company and Takis Biotech announced the production of neutralizing antibodies against SARS-CoV-2 after DNA vaccination in animals. Full Article
dna How Laura Cumming unearthed the truth about her mother's kidnapping, 90 years later By www.cbc.ca Published On :: Fri, 10 Jan 2020 15:09:05 EST The Edinburgh-born art critic and biographer spoke with Eleanor Wachtel about investigating the real story behind her mother’s disappearance as a child in 1929. Full Article Radio/Writers & Company
dna Mating echidnas of Moonie keep outback family up all night, but citizen science provides silver lining By www.abc.net.au Published On :: Thu, 01 Aug 2019 08:00:00 +1000 Lynelle Urquhart's home on a property west of Moonie in outback Queensland is normally quiet. But she has been having trouble sleeping lately, thanks to late-night activity under the floorboards. Full Article ABC Southern Queensland southqld Disasters and Accidents:Drought:All Environment:All:All Human Interest:All:All Human Interest:Animals:All Science and Technology:Animals:All Science and Technology:Animals:Mammals Australia:QLD:Moonie 4406 Australia:QLD:Toowoomba 4350
dna Micro Dame Edna portrait on a matchstick By www.abc.net.au Published On :: Wed, 14 Aug 2019 10:35:00 +1000 Full Article ABC Sunshine Coast sunshine Arts and Entertainment:Visual Art:Painting Australia:QLD:Montville 4560
dna Micro Dame Edna portrait with 20 cent piece for comparison By www.abc.net.au Published On :: Wed, 14 Aug 2019 10:35:00 +1000 Full Article ABC Sunshine Coast sunshine Arts and Entertainment:All:All Arts and Entertainment:Visual Art:Painting Australia:QLD:Montville 4560
dna All-points alert as echidna forces way into home By www.abc.net.au Published On :: Tue, 05 May 2020 13:45:13 +1000 It's an open-and-shut case of home invasion as a wildlife carer captures Novak the beak-and-enter artist refusing to accept the "no entry" rule. Full Article Animal Behaviour Science and Technology Animal Science Animals Human Interest Animals and Nature
dna Theo Hayez's family outraged over DNA on hat claim by news agency By www.abc.net.au Published On :: Wed, 06 May 2020 13:11:32 +1000 The family of missing backpacker Theo Hayez criticises Belgian media for claiming DNA on a cap found near Cape Byron Lighthouse suggested it was owned by the teen, who has not been seen for almost a year. Full Article Law Crime and Justice Police Missing Person Community and Society Death Grief
dna Dancers perform a creation dance of the goanna, kangaroo, emu and echidna at the Wagga Wagga corroboree By www.abc.net.au Published On :: Mon, 28 Oct 2019 16:33:00 +1100 Full Article ABC Riverina riverina Arts and Entertainment:Dance:All Community and Society:History:All Community and Society:Indigenous (Aboriginal and Torres Strait Islander):Aboriginal Community and Society:Indigenous (Aboriginal and Torres Strait Islander):Aboriginal Language Community and Society:Indigenous (Aboriginal and Torres Strait Islander):Indigenous Culture Australia:NSW:Wagga Wagga 2650
dna Jon Rowdon with Buffy the echidna By www.abc.net.au Published On :: Fri, 03 May 2019 19:17:00 +1000 Full Article ABC Ballarat ballarat Human Interest:Animals:All Science and Technology:Animals:Animal Behaviour Australia:VIC:Hepburn Springs 3461
dna Echidna waddles into a fruit shop and Robert Irwin returns it to the wild By www.abc.net.au Published On :: Tue, 21 May 2019 15:22:00 +1000 Robert Irwin comes to the rescue when an echidna waddles into a Sunshine Coast fruit shop and wedges itself under a fridge. Full Article ABC Local sunshine Human Interest:Animals:All Australia:QLD:Maroochydore 4558
dna Footage emerges of echidna swimming in waters on South Australia's Kangaroo Island By www.abc.net.au Published On :: Mon, 07 Oct 2019 17:09:00 +1100 Footage emerges of an echidna cooling off in the warmer weather with a swim on South Australia's Kangaroo Island. One expert says it is not uncommon to see them in water on hot days. Full Article 639 ABC North and West adelaide northandwest Arts and Entertainment:Kids Games and Links:Animals and Nature Human Interest:All:All Human Interest:Animals:All Science and Technology:Animals:All Science and Technology:Animals:Mammals Sport:Swimming:All Australia:All:All Australia:SA:Adelaide 5000 Australia:SA:All Australia:SA:American River 5221 Australia:SA:Kingscote 5223 Australia:SA:Penneshaw 5222
dna Kelpie DNA study unravels mysterious origins of Australian working dog, but finds no dingo By www.abc.net.au Published On :: Fri, 28 Jun 2019 08:18:00 +1000 The Australian kelpie's origins have long been shrouded in mystery, but new genetics research has found some vital answers to the iconic working dog's ancestry. Full Article ABC Kimberley sydney southwestvic kimberley perth Human Interest:All:All Human Interest:Animals:All Rural:Farm Labour:All Rural:Livestock:Beef Cattle Rural:Livestock:Sheep Production Science and Technology:All:All Science and Technology:Animals:All Science and Technology:Animals:Animal Behaviour Australia:NSW:The University of Sydney 2006 Australia:VIC:Casterton 3311 Australia:WA:Kununurra 6743 Australia:WA:Perth 6000 United Kingdom:Scotland:All
dna Woman charged over Bendigo child stealing to be forced to provide DNA sample By www.abc.net.au Published On :: Tue, 05 Nov 2019 14:20:00 +1100 A Bendigo court orders a woman charged with child stealing to provide a DNA sample after she refused to cooperate with authorities. Her lawyer says the woman remains in hospital waiting for an MRI test. Full Article ABC Central Victoria centralvic melbourne Community and Society:Family and Children:All Community and Society:Family and Children:Children Law Crime and Justice:All:All Law Crime and Justice:Courts and Trials:All Law Crime and Justice:Crime:All Australia:VIC:Bendigo 3550 Australia:VIC:Melbourne 3000
dna Case dropped against man accused of attempting to kidnap 6yo at caravan park By www.abc.net.au Published On :: Thu, 19 Sep 2019 15:06:00 +1000 The case against Queensland man Ronald John Toft, who was accused of trying to kidnap a six-year-old girl at an Adelaide caravan park earlier this year, is dropped. Full Article ABC North Queensland northqld adelaide Community and Society:All:All Community and Society:Family and Children:All Law Crime and Justice:All:All Law Crime and Justice:Courts and Trials:All Australia:All:All Australia:QLD:All Australia:QLD:Lucinda 4850 Australia:SA:Adelaide 5000 Australia:SA:All Australia:SA:West Beach 5024
dna DNA confirms 'seriously cute' pup is all dingo By www.abc.net.au Published On :: Fri, 01 Nov 2019 14:14:00 +1100 Full Article ABC Goulburn Murray goulburnmurray Environment:All:All Environment:Pests:All Human Interest:All:All Human Interest:Animals:All Rural:All:All Rural:Pest Management:All Rural:Veterinary Medicine:All Science and Technology:All:All Science and Technology:Animals:All Science and Technology:Animals:Animal Behaviour Australia:All:All Australia:VIC:All Australia:VIC:Wandiligong 3744
dna Mixed-breed DNA test By www.abc.net.au Published On :: Sat, 05 Oct 2019 18:51:00 +1000 Full Article ABC Radio Darwin darwin Community and Society:All:All Community and Society:Charities and Community Organisations:All Community and Society:Indigenous (Aboriginal and Torres Strait Islander):Aboriginal Human Interest:All:All Human Interest:Animals:All Human Interest:Offbeat:All Lifestyle and Leisure:Lifestyle:All Rural:Community Development:All Rural:Livestock:Animal Nutrition Science and Technology:Animals:Animal Behaviour Australia:NT:Darwin 0800
dna Modern transgender family: The naturally conceived Canberra baby with DNA from both of his parents By www.abc.net.au Published On :: Thu, 26 Sep 2019 08:14:00 +1000 The Sutherlands hope that telling their story will help transgender parents be accepted to the point where, one day, "no-one bats an eyelid". Full Article ABC Radio Canberra canberra Community and Society:All:All Community and Society:Family and Children:All Community and Society:Family and Children:Marriage Community and Society:Sexuality:All Health:All:All Health:Reproduction and Contraception:All Health:Reproduction and Contraception:Pregnancy and Childbirth Australia:ACT:All Australia:ACT:Canberra 2600
dna Canberra man kidnapped and 'sadistically' tortured for nine hours over $450, court hears By www.abc.net.au Published On :: Wed, 09 Oct 2019 14:06:00 +1100 A Canberra man was told by a trio of kidnappers that his genitals would be cut off and that he would "die" for an alleged debt of $450 that he used to send to his family in Africa, a court has heard. Full Article ABC Radio Canberra canberra Law Crime and Justice:All:All Law Crime and Justice:Courts and Trials:All Australia:ACT:All Australia:ACT:Canberra 2600 Australia:ACT:Moncrieff 2914
dna Family of Irma Palasics, brutally killed 20 years ago, call for new DNA testing in search for killer By www.abc.net.au Published On :: Sun, 03 Nov 2019 10:56:00 +1100 Irma Palasics was killed during a brutal home invasion in 1999, but her killers were never identified. Twenty years later, her family believe new forensic procedures could find the people responsible. Full Article ABC Radio Canberra canberra Law Crime and Justice:All:All Law Crime and Justice:Crime:All Law Crime and Justice:Police:All Australia:ACT:All Australia:ACT:Canberra 2600 Australia:All:All
dna NSW Police charge man who allegedly kidnapped and sexually assaulted schoolgirl By www.abc.net.au Published On :: Sat, 26 Aug 2017 14:27:00 +1000 NSW Police charge a man who allegedly wore a camouflage suit as he abducted and sexually assaulted a 12-year-old girl while she was walking to school on the Central Coast three months ago. Full Article ABC Radio Central Coast centralcoast Law Crime and Justice:All:All Law Crime and Justice:Sexual Offences:All Australia:NSW:Wyong 2259
dna Friednash: Lessons of the Greatest Generation will help us and defeat our silent, deadly enemy By feeds.denverpost.com Published On :: Fri, 24 Apr 2020 14:00:59 +0000 Each of us is morally and ethically called upon to do the right thing, make sacrifices, and take the necessary steps to keep our family, friends, co-workers and community safe. Full Article Opinion Opinion Columnists Perspective 9/11 coronavirus coronavirus in Colorado culture depression Doug Friednash economy government Great Depression health jobs John Hickenlooper Wall Street World War II
dna Friednash: Deploy federal funds to feed seniors and rescue Colorado’s restaurants By feeds.denverpost.com Published On :: Thu, 07 May 2020 13:00:06 +0000 The restaurant industry predicts that as many as 30% of all Denver restaurants and 22% statewide may permanently go out of business if they can’t open before the end of May. Full Article Opinion Opinion Columnists Perspective budget business closures California child care Denver restaurants employment FEMA financial government grocery stores health hospitals infrastructure manufacturing restaurants sales tax tax
dna Friednash: Deploy federal funds to feed seniors and rescue Colorado’s restaurants By feeds.denverpost.com Published On :: Thu, 07 May 2020 13:00:06 +0000 The restaurant industry predicts that as many as 30% of all Denver restaurants and 22% statewide may permanently go out of business if they can’t open before the end of May. Full Article Opinion Opinion Columnists Perspective budget business closures California child care Denver restaurants employment FEMA financial government grocery stores health hospitals infrastructure manufacturing restaurants sales tax tax
dna Friednash: Deploy federal funds to feed seniors and rescue Colorado’s restaurants By feeds.denverpost.com Published On :: Thu, 07 May 2020 13:00:06 +0000 The restaurant industry predicts that as many as 30% of all Denver restaurants and 22% statewide may permanently go out of business if they can’t open before the end of May. Full Article Opinion Opinion Columnists Perspective budget business closures California child care Denver restaurants employment FEMA financial government grocery stores health hospitals infrastructure manufacturing restaurants sales tax tax
dna BET House Party Presents: Jaime Broadnax By feeds.bet.com Published On :: Tue, 28 Apr 2020 10:36:00 EDT Join us on Facebook Live today! Full Article National News
dna Jessica Jones has a heart to heart moment with her kidnapper daughter By scans-daily.dreamwidth.org Published On :: Sat, 09 May 2020 17:44:59 GMT Posted by: brerrabbit( Read more... ) comments Full Article char: purple girl/kara killgrave creator: filipe andrade title: jessica jones creator: kelly thompson char: jewel/jessica jones
dna Geneticists pump the brakes on DNA, revealing key developmental process By www.princeton.edu Published On :: Thu, 05 Mar 2020 11:43:28 -0500 Researchers at Princeton have revealed the inner workings of a gene repression mechanism in fruit fly embryos, adding insight to the study of human diseases. Full Article
dna With new DNA analysis, the Neanderthal story gets even more complex By www.pbs.org Published On :: A new study reveals that some European Neanderthals might have displaced their relatives in Siberia, while others mingled with another, still mysterious, ancient human population. Full Article
dna In a controversial study, DNA from today’s southern Africans hints at possible “homeland” for modern humans By www.pbs.org Published On :: But many questions remain about the true origin of the Homo sapiens species. Full Article
dna Dogs, drones, and DNA: How eight “extinct” species were rediscovered By www.pbs.org Published On :: A giant tortoise, a seabird, and a gecko all went undetected by scientists for more than a century. Full Article
dna News24.com | Pirates kidnap 6 crewmen from 2 fishing boats off Gabon: source By www.news24.com Published On :: Tue, 05 May 2020 11:20:38 +0200 Pirates have attacked two fishing vessels near the Gabonese capital Libreville, abducting six crewmen, a source close to the Gabonese government told AFP. Full Article
dna For Some Refugees, Safe Haven Now Depends on a DNA Test By feedproxy.google.com Published On :: Mon, 19 Oct 2015 15:43:58 EST Changes to a program designed to reunite refugees with family in the U.S. have slowed -- and in some cases outright denied -- legitimate entries into the country. Full Article
dna A comprehensive evaluation of a typical plant telomeric G-quadruplex (G4) DNA reveals the dynamics of G4 formation, rearrangement, and unfolding [Plant Biology] By feedproxy.google.com Published On :: 2020-04-17T00:06:05-07:00 Telomeres are specific nucleoprotein structures that are located at the ends of linear eukaryotic chromosomes and play crucial roles in genomic stability. Telomere DNA consists of simple repeats of a short G-rich sequence: TTAGGG in mammals and TTTAGGG in most plants. In recent years, the mammalian telomeric G-rich repeats have been shown to form G-quadruplex (G4) structures, which are crucial for modulating telomere functions. Surprisingly, even though plant telomeres are essential for plant growth, development, and environmental adaptions, only few reports exist on plant telomeric G4 DNA (pTG4). Here, using bulk and single-molecule assays, including CD spectroscopy, and single-molecule FRET approaches, we comprehensively characterized the structure and dynamics of a typical plant telomeric sequence, d[GGG(TTTAGGG)3]. We found that this sequence can fold into mixed G4s in potassium, including parallel and antiparallel structures. We also directly detected intermediate dynamic transitions, including G-hairpin, parallel G-triplex, and antiparallel G-triplex structures. Moreover, we observed that pTG4 is unfolded by the AtRecQ2 helicase but not by AtRecQ3. The results of our work shed light on our understanding about the existence, topological structures, stability, intermediates, unwinding, and functions of pTG4. Full Article
dna The histone H4 basic patch regulates SAGA-mediated H2B deubiquitination and histone acetylation [DNA and Chromosomes] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Histone H2B monoubiquitylation (H2Bub1) has central functions in multiple DNA-templated processes, including gene transcription, DNA repair, and replication. H2Bub1 also is required for the trans-histone regulation of H3K4 and H3K79 methylation. Although previous studies have elucidated the basic mechanisms that establish and remove H2Bub1, we have only an incomplete understanding of how H2Bub1 is regulated. We report here that the histone H4 basic patch regulates H2Bub1. Yeast cells with arginine-to-alanine mutations in the H4 basic patch (H42RA) exhibited a significant loss of global H2Bub1. H42RA mutant yeast strains also displayed chemotoxin sensitivities similar to, but less severe than, strains containing a complete loss of H2Bub1. We found that the H4 basic patch regulates H2Bub1 levels independently of interactions with chromatin remodelers and separately from its regulation of H3K79 methylation. To measure H2B ubiquitylation and deubiquitination kinetics in vivo, we used a rapid and reversible optogenetic tool, the light-inducible nuclear exporter, to control the subcellular location of the H2Bub1 E3 ligase, Bre1. The ability of Bre1 to ubiquitylate H2B was unaffected in the H42RA mutant. In contrast, H2Bub1 deubiquitination by SAGA-associated Ubp8, but not by Ubp10, increased in the H42RA mutant. Consistent with a function for the H4 basic patch in regulating SAGA deubiquitinase activity, we also detected increased SAGA-mediated histone acetylation in H4 basic patch mutants. Our findings uncover that the H4 basic patch has a regulatory function in SAGA-mediated histone modifications. Full Article
dna Impact of 1,N6-ethenoadenosine, a damaged ribonucleotide in DNA, on translesion synthesis and repair [Enzymology] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 Incorporation of ribonucleotides into DNA can severely diminish genome integrity. However, how ribonucleotides instigate DNA damage is poorly understood. In DNA, they can promote replication stress and genomic instability and have been implicated in several diseases. We report here the impact of the ribonucleotide rATP and of its naturally occurring damaged analog 1,N6-ethenoadenosine (1,N6-ϵrA) on translesion synthesis (TLS), mediated by human DNA polymerase η (hpol η), and on RNase H2–mediated incision. Mass spectral analysis revealed that 1,N6-ϵrA in DNA generates extensive frameshifts during TLS, which can lead to genomic instability. Moreover, steady-state kinetic analysis of the TLS process indicated that deoxypurines (i.e. dATP and dGTP) are inserted predominantly opposite 1,N6-ϵrA. We also show that hpol η acts as a reverse transcriptase in the presence of damaged ribonucleotide 1,N6-ϵrA but has poor RNA primer extension activities. Steady-state kinetic analysis of reverse transcription and RNA primer extension showed that hpol η favors the addition of dATP and dGTP opposite 1,N6-ϵrA. We also found that RNase H2 recognizes 1,N6-ϵrA but has limited incision activity across from this lesion, which can lead to the persistence of this detrimental DNA adduct. We conclude that the damaged and unrepaired ribonucleotide 1,N6-ϵrA in DNA exhibits mutagenic potential and can also alter the reading frame in an mRNA transcript because 1,N6-ϵrA is incompletely incised by RNase H2. Full Article
dna A comprehensive evaluation of a typical plant telomeric G-quadruplex (G4) DNA reveals the dynamics of G4 formation, rearrangement, and unfolding [Plant Biology] By feedproxy.google.com Published On :: 2020-04-17T00:06:05-07:00 Telomeres are specific nucleoprotein structures that are located at the ends of linear eukaryotic chromosomes and play crucial roles in genomic stability. Telomere DNA consists of simple repeats of a short G-rich sequence: TTAGGG in mammals and TTTAGGG in most plants. In recent years, the mammalian telomeric G-rich repeats have been shown to form G-quadruplex (G4) structures, which are crucial for modulating telomere functions. Surprisingly, even though plant telomeres are essential for plant growth, development, and environmental adaptions, only few reports exist on plant telomeric G4 DNA (pTG4). Here, using bulk and single-molecule assays, including CD spectroscopy, and single-molecule FRET approaches, we comprehensively characterized the structure and dynamics of a typical plant telomeric sequence, d[GGG(TTTAGGG)3]. We found that this sequence can fold into mixed G4s in potassium, including parallel and antiparallel structures. We also directly detected intermediate dynamic transitions, including G-hairpin, parallel G-triplex, and antiparallel G-triplex structures. Moreover, we observed that pTG4 is unfolded by the AtRecQ2 helicase but not by AtRecQ3. The results of our work shed light on our understanding about the existence, topological structures, stability, intermediates, unwinding, and functions of pTG4. Full Article
dna Single-molecule level structural dynamics of DNA unwinding by human mitochondrial Twinkle helicase [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-04-24T06:08:45-07:00 Knowledge of the molecular events in mitochondrial DNA (mtDNA) replication is crucial to understanding the origins of human disorders arising from mitochondrial dysfunction. Twinkle helicase is an essential component of mtDNA replication. Here, we employed atomic force microscopy imaging in air and liquids to visualize ring assembly, DNA binding, and unwinding activity of individual Twinkle hexamers at the single-molecule level. We observed that the Twinkle subunits self-assemble into hexamers and higher-order complexes that can switch between open and closed-ring configurations in the absence of DNA. Our analyses helped visualize Twinkle loading onto and unloading from DNA in an open-ringed configuration. They also revealed that closed-ring conformers bind and unwind several hundred base pairs of duplex DNA at an average rate of ∼240 bp/min. We found that the addition of mitochondrial single-stranded (ss) DNA–binding protein both influences the ways Twinkle loads onto defined DNA substrates and stabilizes the unwound ssDNA product, resulting in a ∼5-fold stimulation of the apparent DNA-unwinding rate. Mitochondrial ssDNA-binding protein also increased the estimated translocation processivity from 1750 to >9000 bp before helicase disassociation, suggesting that more than half of the mitochondrial genome could be unwound by Twinkle during a single DNA-binding event. The strategies used in this work provide a new platform to examine Twinkle disease variants and the core mtDNA replication machinery. They also offer an enhanced framework to investigate molecular mechanisms underlying deletion and depletion of the mitochondrial genome as observed in mitochondrial diseases. Full Article
dna Atomic force microscopy-based characterization of the interaction of PriA helicase with stalled DNA replication forks [DNA and Chromosomes] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 In bacteria, the restart of stalled DNA replication forks requires the DNA helicase PriA. PriA can recognize and remodel abandoned DNA replication forks, unwind DNA in the 3'-to-5' direction, and facilitate the loading of the helicase DnaB onto the DNA to restart replication. Single-stranded DNA–binding protein (SSB) is typically present at the abandoned forks, but it is unclear how SSB and PriA interact, although it has been shown that the two proteins interact both physically and functionally. Here, we used atomic force microscopy to visualize the interaction of PriA with DNA substrates with or without SSB. These experiments were done in the absence of ATP to delineate the substrate recognition pattern of PriA before its ATP-catalyzed DNA-unwinding reaction. These analyses revealed that in the absence of SSB, PriA binds preferentially to a fork substrate with a gap in the leading strand. Such a preference has not been observed for 5'- and 3'-tailed duplexes, suggesting that it is the fork structure that plays an essential role in PriA's selection of DNA substrates. Furthermore, we found that in the absence of SSB, PriA binds exclusively to the fork regions of the DNA substrates. In contrast, fork-bound SSB loads PriA onto the duplex DNA arms of forks, suggesting a remodeling of PriA by SSB. We also demonstrate that the remodeling of PriA requires a functional C-terminal domain of SSB. In summary, our atomic force microscopy analyses reveal key details in the interactions between PriA and stalled DNA replication forks with or without SSB. Full Article
dna Chemical roadblocking of DNA transcription for nascent RNA display [RNA] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Site-specific arrest of RNA polymerases (RNAPs) is fundamental to several technologies that assess RNA structure and function. Current in vitro transcription “roadblocking” approaches inhibit transcription elongation by blocking RNAP with a protein bound to the DNA template. One limitation of protein-mediated transcription roadblocking is that it requires inclusion of a protein factor extrinsic to the minimal in vitro transcription reaction. In this work, we developed a chemical approach for halting transcription by Escherichia coli RNAP. We first established a sequence-independent method for site-specific incorporation of chemical lesions into dsDNA templates by sequential PCR and translesion synthesis. We then show that interrupting the transcribed DNA strand with an internal desthiobiotin-triethylene glycol modification or 1,N6-etheno-2'-deoxyadenosine base efficiently and stably halts Escherichia coli RNAP transcription. By encoding an intrinsic stall site within the template DNA, our chemical transcription roadblocking approach enables display of nascent RNA molecules from RNAP in a minimal in vitro transcription reaction. Full Article
dna A comprehensive evaluation of a typical plant telomeric G-quadruplex (G4) DNA reveals the dynamics of G4 formation, rearrangement, and unfolding [Plant Biology] By www.jbc.org Published On :: 2020-04-17T00:06:05-07:00 Telomeres are specific nucleoprotein structures that are located at the ends of linear eukaryotic chromosomes and play crucial roles in genomic stability. Telomere DNA consists of simple repeats of a short G-rich sequence: TTAGGG in mammals and TTTAGGG in most plants. In recent years, the mammalian telomeric G-rich repeats have been shown to form G-quadruplex (G4) structures, which are crucial for modulating telomere functions. Surprisingly, even though plant telomeres are essential for plant growth, development, and environmental adaptions, only few reports exist on plant telomeric G4 DNA (pTG4). Here, using bulk and single-molecule assays, including CD spectroscopy, and single-molecule FRET approaches, we comprehensively characterized the structure and dynamics of a typical plant telomeric sequence, d[GGG(TTTAGGG)3]. We found that this sequence can fold into mixed G4s in potassium, including parallel and antiparallel structures. We also directly detected intermediate dynamic transitions, including G-hairpin, parallel G-triplex, and antiparallel G-triplex structures. Moreover, we observed that pTG4 is unfolded by the AtRecQ2 helicase but not by AtRecQ3. The results of our work shed light on our understanding about the existence, topological structures, stability, intermediates, unwinding, and functions of pTG4. Full Article
dna Proline-rich 11 (PRR11) drives F-actin assembly by recruiting the actin-related protein 2/3 complex in human non-small cell lung carcinoma [DNA and Chromosomes] By www.jbc.org Published On :: 2020-04-17T00:06:05-07:00 The actin cytoskeleton is extremely dynamic and supports diverse cellular functions in many physiological and pathological processes, including tumorigenesis. However, the mechanisms that regulate the actin-related protein 2/3 (ARP2/3) complex and thereby promote actin polymerization and organization in cancer cells are not well-understood. We previously implicated the proline-rich 11 (PRR11) protein in lung cancer development. In this study, using immunofluorescence staining, actin polymerization assays, and siRNA-mediated gene silencing, we uncovered that cytoplasmic PRR11 is involved in F-actin polymerization and organization. We found that dysregulation of PRR11 expression results in F-actin rearrangement and nuclear instability in non-small cell lung cancer cells. Results from molecular mechanistic experiments indicated that PRR11 associates with and recruits the ARP2/3 complex, facilitates F-actin polymerization, and thereby disrupts the F-actin cytoskeleton, leading to abnormal nuclear lamina assembly and chromatin reorganization. Inhibition of the ARP2/3 complex activity abolished irregular F-actin polymerization, lamina assembly, and chromatin reorganization due to PRR11 overexpression. Notably, experiments with truncated PRR11 variants revealed that PRR11 regulates F-actin through different regions. We found that deletion of either the N or C terminus of PRR11 abrogates its effects on F-actin polymerization and nuclear instability and that deletion of amino acid residues 100–184 or 100–200 strongly induces an F-actin structure called the actin comet tail, not observed with WT PRR11. Our findings indicate that cytoplasmic PRR11 plays an essential role in regulating F-actin assembly and nuclear stability by recruiting the ARP2/3 complex in human non-small cell lung carcinoma cells. Full Article
dna Single-molecule level structural dynamics of DNA unwinding by human mitochondrial Twinkle helicase [Molecular Biophysics] By www.jbc.org Published On :: 2020-04-24T06:08:45-07:00 Knowledge of the molecular events in mitochondrial DNA (mtDNA) replication is crucial to understanding the origins of human disorders arising from mitochondrial dysfunction. Twinkle helicase is an essential component of mtDNA replication. Here, we employed atomic force microscopy imaging in air and liquids to visualize ring assembly, DNA binding, and unwinding activity of individual Twinkle hexamers at the single-molecule level. We observed that the Twinkle subunits self-assemble into hexamers and higher-order complexes that can switch between open and closed-ring configurations in the absence of DNA. Our analyses helped visualize Twinkle loading onto and unloading from DNA in an open-ringed configuration. They also revealed that closed-ring conformers bind and unwind several hundred base pairs of duplex DNA at an average rate of ∼240 bp/min. We found that the addition of mitochondrial single-stranded (ss) DNA–binding protein both influences the ways Twinkle loads onto defined DNA substrates and stabilizes the unwound ssDNA product, resulting in a ∼5-fold stimulation of the apparent DNA-unwinding rate. Mitochondrial ssDNA-binding protein also increased the estimated translocation processivity from 1750 to >9000 bp before helicase disassociation, suggesting that more than half of the mitochondrial genome could be unwound by Twinkle during a single DNA-binding event. The strategies used in this work provide a new platform to examine Twinkle disease variants and the core mtDNA replication machinery. They also offer an enhanced framework to investigate molecular mechanisms underlying deletion and depletion of the mitochondrial genome as observed in mitochondrial diseases. Full Article
dna CRISPR-Cas12a has widespread off-target and dsDNA-nicking effects [DNA and Chromosomes] By www.jbc.org Published On :: 2020-04-24T06:08:45-07:00 Cas12a (Cpf1) is an RNA-guided endonuclease in the bacterial type V-A CRISPR-Cas anti-phage immune system that can be repurposed for genome editing. Cas12a can bind and cut dsDNA targets with high specificity in vivo, making it an ideal candidate for expanding the arsenal of enzymes used in precise genome editing. However, this reported high specificity contradicts Cas12a's natural role as an immune effector against rapidly evolving phages. Here, we employed high-throughput in vitro cleavage assays to determine and compare the native cleavage specificities and activities of three different natural Cas12a orthologs (FnCas12a, LbCas12a, and AsCas12a). Surprisingly, we observed pervasive sequence-specific nicking of randomized target libraries, with strong nicking of DNA sequences containing up to four mismatches in the Cas12a-targeted DNA-RNA hybrid sequences. We also found that these nicking and cleavage activities depend on mismatch type and position and vary with Cas12a ortholog and CRISPR RNA sequence. Our analysis further revealed robust nonspecific nicking of dsDNA when Cas12a is activated by binding to a target DNA. Together, our findings reveal that Cas12a has multiple nicking activities against dsDNA substrates and that these activities vary among different Cas12a orthologs. Full Article
dna Withdrawal: miR-21-mediated radioresistance occurs via promoting repair of DNA double strand breaks. [Withdrawals/Retractions] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 VOLUME 292 (2017) PAGES 3531–3540This article has been withdrawn by Shuofeng Hu, Xiaomin Ying, Xiangming Zhang, and Ya Wang. Baocheng Hu, Xiang Wang, Ping Wang, Jian Wang, and Hongyan Wang could not be reached. In Fig. 1C, the DAPI and merged images for the no IR control were switched. The DNA-PKcs and actin immunoblots on the left appear to have been spliced. In Fig. 4C, the DNA-PKcs immunoblot appears to have been spliced. In Fig. 4D, lanes 1 and 5; lanes 2, 6, and 8; and lanes 3 and 7 of the DNA-PKcs immunoblot are the same. In the p-DNA-PKcs immunoblot, lanes 1 and 8, lanes 2 and 6, and lanes 3 and 7 are the same. In the CRY2 immunoblot, lanes 5 and 7 are the same. In the CDC25A immunoblot, lanes 3 and 8 are the same. In the GSK3B immunoblot, lanes 1 and 5 and lanes 3 and 7 are the same. Also in the GSK3B immunoblot, the upper GSK3B bands in lanes 6 and 8 are the same. Lanes 4 and 8 of the cyclin D1 immunoblot are the same. In Fig. 5A, the CDC25A immunoblot appears to have been spliced. Also in Fig. 5A, lanes 2–4 and lanes 6–8 of the CDC25A immunoblot are the same. Lanes 4–6 and 7–9 of the actin immunoblot are the same. In Fig. 5C, lane 1 of the CDC25A immunoblot was reused in lane 5, and lanes 3 and 4 were reused in lanes 7 and 8. In the... Full Article
dna Withdrawal: Distinct roles of Ape1 protein, an enzyme involved in DNA repair, in high or low linear energy transfer ionizing radiation-induced cell killing. [Withdrawals/Retractions] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 VOLUME 289 (2014) PAGES 30635–30644This article has been withdrawn by Guangnan Chen, Dongkyoo Park, Francis A. Cucinotta, David S. Yu, Xingming Deng, William S. Dynan, Paul W. Doetsch, and Ya Wang. Hongyan Wang, Xiang Wang, Xiangming Zhang, and Xiaobing Tang could not be reached. The last two lanes of the actin immunoblot in Fig. 1A were reused in the last two lanes of the actin immunoblot in Fig. 1C. In Fig. 2A, the γ-H2AX and the merge with DAPI images for no IR treatment do not match. In Fig. 3A, lanes 3 and 4 of the γ-H2AX immunoblot were reused in lanes 7 and 8, and lanes 5 and 6 of the H2A immunoblot were reused in lanes 7 and 8. In Fig. 3B, lanes 5 and 6 of the H2A immunoblot were reused in lanes 7 and 8. In Fig. 3C, lanes 5 and 6 of the γ-H2AX immunoblot were reused in lanes 7 and 8. Additionally, lanes 1 and 2 of the H2A immunoblot were reused in lanes 3 and 4. In Fig. 3D, lanes 1 and 2 of the Mre11 immunoblot from lysates were reused in lanes 4 and 5. In the γ-H2AX immunoblot, lane 3 was reused in lane 7, and lane 4 was reused in lanes 6 and 8. Also in the H2A immunoblot, lanes 1 and 2 were reused in lanes 3 and 4. In Fig. 4B, lanes 2 and 6 of the Mre11 immunoblot from Ogg1−/− cells are the same. In the Ape1... Full Article
dna Impact of 1,N6-ethenoadenosine, a damaged ribonucleotide in DNA, on translesion synthesis and repair [Enzymology] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 Incorporation of ribonucleotides into DNA can severely diminish genome integrity. However, how ribonucleotides instigate DNA damage is poorly understood. In DNA, they can promote replication stress and genomic instability and have been implicated in several diseases. We report here the impact of the ribonucleotide rATP and of its naturally occurring damaged analog 1,N6-ethenoadenosine (1,N6-ϵrA) on translesion synthesis (TLS), mediated by human DNA polymerase η (hpol η), and on RNase H2–mediated incision. Mass spectral analysis revealed that 1,N6-ϵrA in DNA generates extensive frameshifts during TLS, which can lead to genomic instability. Moreover, steady-state kinetic analysis of the TLS process indicated that deoxypurines (i.e. dATP and dGTP) are inserted predominantly opposite 1,N6-ϵrA. We also show that hpol η acts as a reverse transcriptase in the presence of damaged ribonucleotide 1,N6-ϵrA but has poor RNA primer extension activities. Steady-state kinetic analysis of reverse transcription and RNA primer extension showed that hpol η favors the addition of dATP and dGTP opposite 1,N6-ϵrA. We also found that RNase H2 recognizes 1,N6-ϵrA but has limited incision activity across from this lesion, which can lead to the persistence of this detrimental DNA adduct. We conclude that the damaged and unrepaired ribonucleotide 1,N6-ϵrA in DNA exhibits mutagenic potential and can also alter the reading frame in an mRNA transcript because 1,N6-ϵrA is incompletely incised by RNase H2. Full Article
dna Atomic force microscopy-based characterization of the interaction of PriA helicase with stalled DNA replication forks [DNA and Chromosomes] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 In bacteria, the restart of stalled DNA replication forks requires the DNA helicase PriA. PriA can recognize and remodel abandoned DNA replication forks, unwind DNA in the 3'-to-5' direction, and facilitate the loading of the helicase DnaB onto the DNA to restart replication. Single-stranded DNA–binding protein (SSB) is typically present at the abandoned forks, but it is unclear how SSB and PriA interact, although it has been shown that the two proteins interact both physically and functionally. Here, we used atomic force microscopy to visualize the interaction of PriA with DNA substrates with or without SSB. These experiments were done in the absence of ATP to delineate the substrate recognition pattern of PriA before its ATP-catalyzed DNA-unwinding reaction. These analyses revealed that in the absence of SSB, PriA binds preferentially to a fork substrate with a gap in the leading strand. Such a preference has not been observed for 5'- and 3'-tailed duplexes, suggesting that it is the fork structure that plays an essential role in PriA's selection of DNA substrates. Furthermore, we found that in the absence of SSB, PriA binds exclusively to the fork regions of the DNA substrates. In contrast, fork-bound SSB loads PriA onto the duplex DNA arms of forks, suggesting a remodeling of PriA by SSB. We also demonstrate that the remodeling of PriA requires a functional C-terminal domain of SSB. In summary, our atomic force microscopy analyses reveal key details in the interactions between PriA and stalled DNA replication forks with or without SSB. Full Article
dna Genetic evidence for reconfiguration of DNA polymerase {theta} active site for error-free translesion synthesis in human cells [DNA and Chromosomes] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 The action mechanisms revealed by the biochemical and structural analyses of replicative and translesion synthesis (TLS) DNA polymerases (Pols) are retained in their cellular roles. In this regard, DNA polymerase θ differs from other Pols in that whereas purified Polθ misincorporates an A opposite 1,N6-ethenodeoxyadenosine (ϵdA) using an abasic-like mode, Polθ performs predominantly error-free TLS in human cells. To test the hypothesis that Polθ adopts a different mechanism for replicating through ϵdA in human cells than in the purified Pol, here we analyze the effects of mutations in the two highly conserved tyrosine residues, Tyr-2387 and Tyr-2391, in the Polθ active site. Our findings that these residues are indispensable for TLS by the purified Pol but are not required in human cells, as well as other findings, provide strong evidence that the Polθ active site is reconfigured in human cells to stabilize ϵdA in the syn conformation for Hoogsteen base pairing with the correct nucleotide. The evidence that a DNA polymerase can configure its active site entirely differently in human cells than in the purified Pol establishes a new paradigm for DNA polymerase function. Full Article
dna Icelandic DNA jigsaw-puzzle brings new knowledge about Neanderthals By www.eurekalert.org Published On :: Thu, 23 Apr 2020 00:00:00 EDT (Aarhus University) An international team of researchers has put together a new image of Neanderthals based on the genes Neanderthals left in the DNA of modern humans when they had children with them about 50,000 years ago. The researchers found the new information by trawling the genomes of more than 27,000 Icelanders. Among other things, they discovered that Neanderthal children had older mothers and younger fathers than the Homo-Sapien children in Africa did at the time. Full Article