To meet the low-cost concept advocated by the sodium metal anode,this paper reports the use of a pulsed electrodeposition technology with ionic liquids as electrolytes to achieve uniform nanoplating of metallic magnes...To meet the low-cost concept advocated by the sodium metal anode,this paper reports the use of a pulsed electrodeposition technology with ionic liquids as electrolytes to achieve uniform nanoplating of metallic magnesium films at around 20 nm on spaced titanium dioxide(TiO_(2))nanotubes(STNA-Mg).First,the sodiophilic magnesium metal coating can effectively reduce the nucleation overpotential of sodium metal.Moreover,three-dimensional STNA can limit the volume expansion during sodium metal plating and stripping to achieve the ultrastable deposition and stripping of sodium metals with a high Coulombic efficiency of up to 99.5%and a small voltage polarization of 5 mV in symmetric Na||Na batteries.In addition,the comparative study of sodium metal deposition behavior of STNA-Mg and STNA-Cu prepared by the same route further confirmed the advantage of magnesium metal to guide sodium metal growth.Finally,the prepared STNA-Mg-Na metal anode and commercial sodium vanadium phosphate cathode were assembled into a full cell,delivering a discharge capacity of 110.2 mAh·g^(-1)with a retention rate of 95.6%after 110 cycles at 1C rate.展开更多
In 2023,Baishideng Publishing Group(Baishideng)routinely published 47 openaccess journals,including 46 English-language journals and 1 Chinese-language journal.Our successes were accomplished through the collective de...In 2023,Baishideng Publishing Group(Baishideng)routinely published 47 openaccess journals,including 46 English-language journals and 1 Chinese-language journal.Our successes were accomplished through the collective dedicated efforts of Baishideng staffs,Editorial Board Members,and Peer Reviewers.Among these 47 Baishideng journals,7 are included in the Science Citation Index Expanded(SCIE)and 6 in the Emerging Sources Citation Index(ESCI).With the support of Baishideng authors,company staffs,Editorial Board Members,and Peer Reviewers,the publication work of 2023 is about to be successfully completed.This editorial summarizes the 2023 activities and accomplishments of the 13 SCIEand ESCI-indexed Baishideng journals,outlines the Baishideng publishing policy changes and additions made this year,and highlights the unique advantages of Baishideng journals.展开更多
Background:Patients who survive initial esophagogastric variceal bleeding(EVB)are at an increased risk of recurrent bleeding and death;however,a reliable predictive model is lacking.We aimed to develop a model for reb...Background:Patients who survive initial esophagogastric variceal bleeding(EVB)are at an increased risk of recurrent bleeding and death;however,a reliable predictive model is lacking.We aimed to develop a model for rebleeding prediction in patients with EVB after modified percutaneous transhepatic variceal embolization(PTVE)with cyanoacrylate.Methods:A total of 122 patients with EVB who underwent PTVE from January 2015 to November 2020 were enrolled.Multivariate logistic analyses were conducted to determine independent risk factors for nomogram construction.The discrimination,calibration,and clinical utility of the nomogram were compared with the Model for End-stage Liver Disease score(MELD)and the Child–Pugh model.Risk stratification was performed according to the nomogram.Results:Rebleeding within 3 months of PTVE occurred in 32 patients(26.2%).Independent rebleeding indicators included prior history of endoscopic therapy,Child–Pugh score,partial splenic embolization,and creatinine level.The nomogram incorporating these four predictors achieved excellent calibration and discriminatory abilities,with a concordance index of 0.85,which was confirmed to be 0.83 through bootstrapping validation.The nomogram demonstrated superior discrimination and clinical applicability than the MELD and Child–Pugh models.As shown in the Kaplan–Meier curves,high-risk patients had a high probability of rebleeding(P<0.001).Conclusions:The creatinine-based nomogram had a superior ability to predict rebleeding after PTVE in patients with EVB.Risk stratification may help identify high-risk patients and lead to the earlier implementation of aggressive treatments and formulation of intensive follow-up plans.展开更多
Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9...Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9 ortholog from Staphylococcus aureus(SaCas9), is important in genome editing because it can edit sites with HHHAAT protospacer adjacent motif(PAM) that the canonical Streptococcus pyogenes Cas9(SpCas9) or its variants(e.g. xCas9, Cas9-NG) cannot. However, several technical parameters of SaKKH involved base editors have not been well defined and this uncertainty limits their application. We developed an effective multiplex cytosine base editor(SaKKHn-pBE) and showed that it recognized NNARRT, NNCRRT, NNGRGT, and NNTRGT PAMs. Based on 27 targets tested, we defined technical parameters of SaKKHn-pBE including the editing window, the preferred sequence context, and the mutation type. The editing efficiency was further improved by modification of the SaKKH sgRNA. These advances can be applied in future research and molecular breeding in rice and other plants.展开更多
Persistent hepatic cellular metabolic stress and liver inflammatory stimuli are key signatures of nonalcoholic steatohepatitis(NASH).DDX3X is a vital molecule involved in cell fate decisions in both pro-survival stres...Persistent hepatic cellular metabolic stress and liver inflammatory stimuli are key signatures of nonalcoholic steatohepatitis(NASH).DDX3X is a vital molecule involved in cell fate decisions in both pro-survival stress granule(SG)and pro-death NOD-like receptor family pyrin domain containing 3(NLRP3)inflammasome assembly in response to stress signals.However,the role of DDX3X in NASH remains unclear.We characterized the cell type-specific roles of DDX3X in NASH.Human liver tissues from NASH patients and normal control subjects were collected to assess DDX3X expression and distribution.Nutritional steatohepatitis models were constructed by feeding macrophage-specific DDX3X knockout(DDX3^(XΔMφ)),hepatocyte-specific DDX3X knockout(DDX3X^(Δhep)),and wild-type control(DDX3X^(fl/fl))mice a high-fat and high-cholesterol(HFHC)diet,a methionine-and choline-deficient(MCD)diet,and a high-fat/high-iron/high-fructose/high-cholesterol,low-methionine,and choline-deficient(HFHIHFHC-MCD)diet.The study demonstrated that DDX3X was predominantly expressed in macrophages and hepatocytes in control liver tissues,and its expression was down-regulated in patients or mice with NASH.Compared to DDX3X^(fl/fl) littermates,DDX3^(XΔMφ)mice showed improved liver histology in nutritional steatohepatitis models.Loss of macrophage DDX3X inhibited NLRP3 inflammasome-mediated pyroptosis,causing anti-inflammatory M2 polarization and alleviating hepatocyte steatohepatitic changes.DDX3X^(Δhep) mice developed marked steatohepatitis in multiple nutritional steatohepatitis models compared to DDX3X^(fl/fl) littermates.DDX3X-deleted hepatocytes showed impaired SG assembly,leading to increased sensitivity and intolerance to metabolic stimulation and resultant steatohepatitis.In conclusion,DDX3X plays opposite roles in different cell types during the progression of NASH.A better understanding of the cell-specific differences in the crosstalk between SG formation and NLRP3 activation is crucial for developing prospective targeted DDX3X inhibitors for the treatment of NASH.展开更多
The propensity of metallic Na dendrites from uneven electrodeposits and the low Coulombic efficiency due to the inevitable existence of "dead sodium" are crucial barriers to realizing the Na metal anode.Here...The propensity of metallic Na dendrites from uneven electrodeposits and the low Coulombic efficiency due to the inevitable existence of "dead sodium" are crucial barriers to realizing the Na metal anode.Herein,we report a multifunctional sodiophilic skeleton based on the packing of hard carbon(HC)microspheres for stable sodium metal electrodeposition without "dead sodium".Firstly,HC is sodiophilic substrate due to the intrinsic heteroatoms or defects which is a favor for the nucleation of Na.Secondly,silver nanoparticles electroplating on HC(Ag-HC)was adopted to boost the Na diffusion and further regulate the uniform Na metal epitaxial deposition due to well compatibility with AIMD simulation.Finally,the packing of HC microspheres provides the inner space for Na plating.Importantly,it was first found by Cryo-TEM that Na metal deposition in nanoscale is achieved by oriented attachment along[110]direction,leading to the formation of polycrystalline Na metal film on Ag-HC.Such epitaxial deposition can efficiently reduce the formation of "dead sodium" as revealed by chromatography tests,allowing the high Coulombic efficiency and good cycling stability robust kinetics.Finally,HC-Ag||Na_(3)V_(2)(PO_(4))_(3)full cell with a low negative/positive ratio of 0.6 is firstly achieved and displays good cycling stability.This finding provides a new practical strategy without pre-plating of Na metals and demonstrates a highly reversible polycrystalline Na metal anode toward a high-energy Na-based battery.展开更多
We demonstrate that the Mg-doping in barriers can partially screen the polarization fields of InGaN-based green light-emitting diodes.The photocurrent spectra show that the Mg-doping samples have smaller polarization ...We demonstrate that the Mg-doping in barriers can partially screen the polarization fields of InGaN-based green light-emitting diodes.The photocurrent spectra show that the Mg-doping samples have smaller polarization fields and the blue shift of the peak with increasing current is observed.The reduction of polarization fields can be attributed to the screening of the impurity holes generated by the Mg atoms in the barriers.The efficiency droop is sensitive to the Mg-doping concentration in barriers,while the sample with Mg concentration of 5×10^(19) cm^(-3) exhibits the lowest efficiency degradation of 12.4%at a high injection current.展开更多
Dear Editor,Base editors(BEs)based on the CRISPR/Cas9 system,including cytosine base editors and adenine base editors,which can efficiently perform four transition mutations(C·G-to-T·A and A·T-to-G·...Dear Editor,Base editors(BEs)based on the CRISPR/Cas9 system,including cytosine base editors and adenine base editors,which can efficiently perform four transition mutations(C·G-to-T·A and A·T-to-G·C),have been well studied and widely used to produce base mutations in a variety of organisms,including in plants such as rice.展开更多
A novel high nitrogen medium-entropy alloy CrCoNiN, which had higher strength and slightly lower ductility than CrCoNi alloy, was successfully manufactured by pressurized metallurgy.The microstructure and corrosion be...A novel high nitrogen medium-entropy alloy CrCoNiN, which had higher strength and slightly lower ductility than CrCoNi alloy, was successfully manufactured by pressurized metallurgy.The microstructure and corrosion behaviour were investigated by microscopic, electrochemical and spectroscopic methods. The results indicated that nitrogen existed in the form of Cr2N precipitates and uniformly distributed N atoms, and nitrogen alloying significantly refined the grain size. Besides, nitrogen enriched on the outmost surface of passive film and metal/film interface as ammonia (NH3 and NH4^+) and CrN, respectively. The significant improvement of corrosion resistance of CrCoNiN was attributed to the lower metastahle pitting susceptibility together with thicker, less defective and more compact passive film.展开更多
The development of CRISPR/Cas9-mediated base editing has made genomic modification more efficient. However, selection of genetically modified cells from millions of treated cells, especially plant cells, is still chal...The development of CRISPR/Cas9-mediated base editing has made genomic modification more efficient. However, selection of genetically modified cells from millions of treated cells, especially plant cells, is still challenging. In this study, an efficient surrogate reporter system based on a defective hygromycin resistance gene was established in rice to enrich base-edited cells. After step-by-step optimization, the Discriminated sgRNAs-based SurroGate system (DisSUGs) was established by artificially differentiating the editing abilities of a wild-type single guide RNA (sgRNA) targeting the surrogate reporter gene and an enhanced sgRNA targeting endogenous sites. The DisSUGs enhanced the efficiency of screening base-edited cells by 3- to 5-fold for a PmCDA1-based cytosine-to-tyrosine base editor (PCBE), and 2.5- to 6.5-fold for an adenine base editor (ABE) at endogenous targets. These targets showed editing efficiencies of <25% in the conventional systems. The DisSUGs greatly enhanced the frequency of homozygous substitutions and expanded the activity window slightly for both a PCBE and an ABE. Analyses of the total number of single-nucleotide variants from whole-genome sequencing revealed that, compared with the no-enrichment PCBE strategy, the DisSUGs did not alter the frequency of genome-wide sgRNA-independent off-target mutations, but slightly increased the frequency of target-dependent off-target mutations. Collectively, the DisSUGs developed in this study greatly enhances the efficiency of screening plant base-edited cells and will be a useful system in future applications.展开更多
Dear Editor,Base editors(BEs),including cytosine base editor(CBE)and adenine base editor(ABE),have been widely used to generate irreversible nucleotide substitution in plants and animals.However,their wide application...Dear Editor,Base editors(BEs),including cytosine base editor(CBE)and adenine base editor(ABE),have been widely used to generate irreversible nucleotide substitution in plants and animals.However,their wide applications are largely hindered by the strict NG protospacer adjacent motif(PAM)sequences recognized by Streptococcus pyogenes Cas9(SpCas9)and its engineered variants,such as SpCas9-NG and xCas9(Hua et al.,2019;Ren et al.,2019;Wu et al.,2019;Zhong et al.,2019;Zhang et al.,2020).Most recently,it was reported that three new SpCas9 variants,SpCas9-NRRH,SpCas9-NRTH,and SpCas9-NRCH,could recognize non-G PAMs(NRNH,where R is A or G and H is A,C,or T)in human cells(Miller et al.,2020).Meanwhile,SPRY,another new SpCas9 variant,was developed to greatly expand the editing scope of BEs to nearly PAMless(Walton et al.,2020).In this study,we generated a series of efficient BE toolkits and almost achieved C-to-T mutation without PAM restriction except for NTG PAM,and largely expanded A-to-G mutation scope in stable transformed rice,providing a reference for application in other plants.展开更多
基金financially supported by the National Natural Science Foundation of China (No.51874099)the National Science Foundation of Fujian Province’s Key Project,China (No.2021J02031)the support from the open fund from the Academy of Carbon Neutrality of Fujian Normal University,China (No.CZH2022-06)。
文摘To meet the low-cost concept advocated by the sodium metal anode,this paper reports the use of a pulsed electrodeposition technology with ionic liquids as electrolytes to achieve uniform nanoplating of metallic magnesium films at around 20 nm on spaced titanium dioxide(TiO_(2))nanotubes(STNA-Mg).First,the sodiophilic magnesium metal coating can effectively reduce the nucleation overpotential of sodium metal.Moreover,three-dimensional STNA can limit the volume expansion during sodium metal plating and stripping to achieve the ultrastable deposition and stripping of sodium metals with a high Coulombic efficiency of up to 99.5%and a small voltage polarization of 5 mV in symmetric Na||Na batteries.In addition,the comparative study of sodium metal deposition behavior of STNA-Mg and STNA-Cu prepared by the same route further confirmed the advantage of magnesium metal to guide sodium metal growth.Finally,the prepared STNA-Mg-Na metal anode and commercial sodium vanadium phosphate cathode were assembled into a full cell,delivering a discharge capacity of 110.2 mAh·g^(-1)with a retention rate of 95.6%after 110 cycles at 1C rate.
文摘In 2023,Baishideng Publishing Group(Baishideng)routinely published 47 openaccess journals,including 46 English-language journals and 1 Chinese-language journal.Our successes were accomplished through the collective dedicated efforts of Baishideng staffs,Editorial Board Members,and Peer Reviewers.Among these 47 Baishideng journals,7 are included in the Science Citation Index Expanded(SCIE)and 6 in the Emerging Sources Citation Index(ESCI).With the support of Baishideng authors,company staffs,Editorial Board Members,and Peer Reviewers,the publication work of 2023 is about to be successfully completed.This editorial summarizes the 2023 activities and accomplishments of the 13 SCIEand ESCI-indexed Baishideng journals,outlines the Baishideng publishing policy changes and additions made this year,and highlights the unique advantages of Baishideng journals.
基金the Key Scientific Research Project of Colleges and Universities in Henan Province,China(grant number 17A320011)。
文摘Background:Patients who survive initial esophagogastric variceal bleeding(EVB)are at an increased risk of recurrent bleeding and death;however,a reliable predictive model is lacking.We aimed to develop a model for rebleeding prediction in patients with EVB after modified percutaneous transhepatic variceal embolization(PTVE)with cyanoacrylate.Methods:A total of 122 patients with EVB who underwent PTVE from January 2015 to November 2020 were enrolled.Multivariate logistic analyses were conducted to determine independent risk factors for nomogram construction.The discrimination,calibration,and clinical utility of the nomogram were compared with the Model for End-stage Liver Disease score(MELD)and the Child–Pugh model.Risk stratification was performed according to the nomogram.Results:Rebleeding within 3 months of PTVE occurred in 32 patients(26.2%).Independent rebleeding indicators included prior history of endoscopic therapy,Child–Pugh score,partial splenic embolization,and creatinine level.The nomogram incorporating these four predictors achieved excellent calibration and discriminatory abilities,with a concordance index of 0.85,which was confirmed to be 0.83 through bootstrapping validation.The nomogram demonstrated superior discrimination and clinical applicability than the MELD and Child–Pugh models.As shown in the Kaplan–Meier curves,high-risk patients had a high probability of rebleeding(P<0.001).Conclusions:The creatinine-based nomogram had a superior ability to predict rebleeding after PTVE in patients with EVB.Risk stratification may help identify high-risk patients and lead to the earlier implementation of aggressive treatments and formulation of intensive follow-up plans.
基金supported by the Beijing Scholars Program[BSP041]。
文摘Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9 ortholog from Staphylococcus aureus(SaCas9), is important in genome editing because it can edit sites with HHHAAT protospacer adjacent motif(PAM) that the canonical Streptococcus pyogenes Cas9(SpCas9) or its variants(e.g. xCas9, Cas9-NG) cannot. However, several technical parameters of SaKKH involved base editors have not been well defined and this uncertainty limits their application. We developed an effective multiplex cytosine base editor(SaKKHn-pBE) and showed that it recognized NNARRT, NNCRRT, NNGRGT, and NNTRGT PAMs. Based on 27 targets tested, we defined technical parameters of SaKKHn-pBE including the editing window, the preferred sequence context, and the mutation type. The editing efficiency was further improved by modification of the SaKKH sgRNA. These advances can be applied in future research and molecular breeding in rice and other plants.
基金grants from the National Natural Science Foundation of China(nos.82000548,82100621,82170574,and 81402337)the Funding for Clinical Trials from the Affiliated Drum Tower Hospital,Medical School of Nanjing University(no.2021-LCYJ-PY-4)and the Natural Science Fund of Jiangsu Province(no.BK20210147).
文摘Persistent hepatic cellular metabolic stress and liver inflammatory stimuli are key signatures of nonalcoholic steatohepatitis(NASH).DDX3X is a vital molecule involved in cell fate decisions in both pro-survival stress granule(SG)and pro-death NOD-like receptor family pyrin domain containing 3(NLRP3)inflammasome assembly in response to stress signals.However,the role of DDX3X in NASH remains unclear.We characterized the cell type-specific roles of DDX3X in NASH.Human liver tissues from NASH patients and normal control subjects were collected to assess DDX3X expression and distribution.Nutritional steatohepatitis models were constructed by feeding macrophage-specific DDX3X knockout(DDX3^(XΔMφ)),hepatocyte-specific DDX3X knockout(DDX3X^(Δhep)),and wild-type control(DDX3X^(fl/fl))mice a high-fat and high-cholesterol(HFHC)diet,a methionine-and choline-deficient(MCD)diet,and a high-fat/high-iron/high-fructose/high-cholesterol,low-methionine,and choline-deficient(HFHIHFHC-MCD)diet.The study demonstrated that DDX3X was predominantly expressed in macrophages and hepatocytes in control liver tissues,and its expression was down-regulated in patients or mice with NASH.Compared to DDX3X^(fl/fl) littermates,DDX3^(XΔMφ)mice showed improved liver histology in nutritional steatohepatitis models.Loss of macrophage DDX3X inhibited NLRP3 inflammasome-mediated pyroptosis,causing anti-inflammatory M2 polarization and alleviating hepatocyte steatohepatitic changes.DDX3X^(Δhep) mice developed marked steatohepatitis in multiple nutritional steatohepatitis models compared to DDX3X^(fl/fl) littermates.DDX3X-deleted hepatocytes showed impaired SG assembly,leading to increased sensitivity and intolerance to metabolic stimulation and resultant steatohepatitis.In conclusion,DDX3X plays opposite roles in different cell types during the progression of NASH.A better understanding of the cell-specific differences in the crosstalk between SG formation and NLRP3 activation is crucial for developing prospective targeted DDX3X inhibitors for the treatment of NASH.
基金financially supported by the National Natural Science Foundation of China(NSFC 51874099)the National Science Foundation of Fujian Province’s Key Project(2021J02031)。
文摘The propensity of metallic Na dendrites from uneven electrodeposits and the low Coulombic efficiency due to the inevitable existence of "dead sodium" are crucial barriers to realizing the Na metal anode.Herein,we report a multifunctional sodiophilic skeleton based on the packing of hard carbon(HC)microspheres for stable sodium metal electrodeposition without "dead sodium".Firstly,HC is sodiophilic substrate due to the intrinsic heteroatoms or defects which is a favor for the nucleation of Na.Secondly,silver nanoparticles electroplating on HC(Ag-HC)was adopted to boost the Na diffusion and further regulate the uniform Na metal epitaxial deposition due to well compatibility with AIMD simulation.Finally,the packing of HC microspheres provides the inner space for Na plating.Importantly,it was first found by Cryo-TEM that Na metal deposition in nanoscale is achieved by oriented attachment along[110]direction,leading to the formation of polycrystalline Na metal film on Ag-HC.Such epitaxial deposition can efficiently reduce the formation of "dead sodium" as revealed by chromatography tests,allowing the high Coulombic efficiency and good cycling stability robust kinetics.Finally,HC-Ag||Na_(3)V_(2)(PO_(4))_(3)full cell with a low negative/positive ratio of 0.6 is firstly achieved and displays good cycling stability.This finding provides a new practical strategy without pre-plating of Na metals and demonstrates a highly reversible polycrystalline Na metal anode toward a high-energy Na-based battery.
基金Supported by the Science and Technology Plan of the State Ministry of Science and Technology(No 2011BAE01B17).
文摘We demonstrate that the Mg-doping in barriers can partially screen the polarization fields of InGaN-based green light-emitting diodes.The photocurrent spectra show that the Mg-doping samples have smaller polarization fields and the blue shift of the peak with increasing current is observed.The reduction of polarization fields can be attributed to the screening of the impurity holes generated by the Mg atoms in the barriers.The efficiency droop is sensitive to the Mg-doping concentration in barriers,while the sample with Mg concentration of 5×10^(19) cm^(-3) exhibits the lowest efficiency degradation of 12.4%at a high injection current.
文摘Dear Editor,Base editors(BEs)based on the CRISPR/Cas9 system,including cytosine base editors and adenine base editors,which can efficiently perform four transition mutations(C·G-to-T·A and A·T-to-G·C),have been well studied and widely used to produce base mutations in a variety of organisms,including in plants such as rice.
基金supported by the National Natural Science Foundation of China(Grant Nos.51434004,U1435205,51774074)the Transformation Project of Major Scientific and Technological Achievements in Shenyang(Grant No.Z17-5-003)
文摘A novel high nitrogen medium-entropy alloy CrCoNiN, which had higher strength and slightly lower ductility than CrCoNi alloy, was successfully manufactured by pressurized metallurgy.The microstructure and corrosion behaviour were investigated by microscopic, electrochemical and spectroscopic methods. The results indicated that nitrogen existed in the form of Cr2N precipitates and uniformly distributed N atoms, and nitrogen alloying significantly refined the grain size. Besides, nitrogen enriched on the outmost surface of passive film and metal/film interface as ammonia (NH3 and NH4^+) and CrN, respectively. The significant improvement of corrosion resistance of CrCoNiN was attributed to the lower metastahle pitting susceptibility together with thicker, less defective and more compact passive film.
基金This work was supported by Beijing Academy of Agriculture&Forestry Scien ces,Beijing,ChinaThe funding in eluded Innovative Team Con-struction Project of BAAFS(JNKYT201603)the Beijing Scholars Program(BSP041).
文摘The development of CRISPR/Cas9-mediated base editing has made genomic modification more efficient. However, selection of genetically modified cells from millions of treated cells, especially plant cells, is still challenging. In this study, an efficient surrogate reporter system based on a defective hygromycin resistance gene was established in rice to enrich base-edited cells. After step-by-step optimization, the Discriminated sgRNAs-based SurroGate system (DisSUGs) was established by artificially differentiating the editing abilities of a wild-type single guide RNA (sgRNA) targeting the surrogate reporter gene and an enhanced sgRNA targeting endogenous sites. The DisSUGs enhanced the efficiency of screening base-edited cells by 3- to 5-fold for a PmCDA1-based cytosine-to-tyrosine base editor (PCBE), and 2.5- to 6.5-fold for an adenine base editor (ABE) at endogenous targets. These targets showed editing efficiencies of <25% in the conventional systems. The DisSUGs greatly enhanced the frequency of homozygous substitutions and expanded the activity window slightly for both a PCBE and an ABE. Analyses of the total number of single-nucleotide variants from whole-genome sequencing revealed that, compared with the no-enrichment PCBE strategy, the DisSUGs did not alter the frequency of genome-wide sgRNA-independent off-target mutations, but slightly increased the frequency of target-dependent off-target mutations. Collectively, the DisSUGs developed in this study greatly enhances the efficiency of screening plant base-edited cells and will be a useful system in future applications.
基金This work was supported by Beijing Academy of Agriculture&Forestry SciencesThe funding included Beijing Municipal Natural Science Foundation(6204041)the Beijing Scholars Program(BSP041).
文摘Dear Editor,Base editors(BEs),including cytosine base editor(CBE)and adenine base editor(ABE),have been widely used to generate irreversible nucleotide substitution in plants and animals.However,their wide applications are largely hindered by the strict NG protospacer adjacent motif(PAM)sequences recognized by Streptococcus pyogenes Cas9(SpCas9)and its engineered variants,such as SpCas9-NG and xCas9(Hua et al.,2019;Ren et al.,2019;Wu et al.,2019;Zhong et al.,2019;Zhang et al.,2020).Most recently,it was reported that three new SpCas9 variants,SpCas9-NRRH,SpCas9-NRTH,and SpCas9-NRCH,could recognize non-G PAMs(NRNH,where R is A or G and H is A,C,or T)in human cells(Miller et al.,2020).Meanwhile,SPRY,another new SpCas9 variant,was developed to greatly expand the editing scope of BEs to nearly PAMless(Walton et al.,2020).In this study,we generated a series of efficient BE toolkits and almost achieved C-to-T mutation without PAM restriction except for NTG PAM,and largely expanded A-to-G mutation scope in stable transformed rice,providing a reference for application in other plants.