DNA double-strand breaks （DSBs） are introduced in cells by ionizing radiation and reactive oxygen species. In addition, they are commonly generated during V（D）J recombination, an essential aspect of the developing...DNA double-strand breaks （DSBs） are introduced in cells by ionizing radiation and reactive oxygen species. In addition, they are commonly generated during V（D）J recombination, an essential aspect of the developing immune system. Failure to effectively repair these DSBs can result in chromosome breakage, cell death, onset of cancer, and defects in the immune system of higher vertebrates. Fortunately, all mammalian cells possess two enzymatic pathways that mediate the repair of DSBs： homologous recombination and non-homologous end-joining （NHEJ）. The NHEJ process utilizes enzymes that capture both ends of the broken DNA molecule, bring them together in a synaptic DNA-protein complex, and finally repair the DNA break. In this review, all the known enzymes that play a role in the NHEJ process are discussed and a working model for the co-operation of these enzymes during DSB repair is presented.展开更多
The genomes of eukaryotic cells are under continuous assault by environmental agents and endogenous metabolic byproducts. Damage induced in DNA usually leads to a cascade of cellular events, the DNA damage response. F...The genomes of eukaryotic cells are under continuous assault by environmental agents and endogenous metabolic byproducts. Damage induced in DNA usually leads to a cascade of cellular events, the DNA damage response. Failure of the DNA damage response can lead to development of malignancy by reducing the efficiency and fidelity of DNA repair. The NBS1 protein is a component of the MRE11/RAD50/NBS 1 complex （MRN） that plays a critical role in the cellular response to DNA damage and the maintenance of chromosomal integrity. Mutations in the NBS1 gene are responsible for Nijmegen breakage syndrome （NBS）, a hereditary disorder that imparts an increased predisposition to development of malignancy. The phenotypic characteristics of cells isolated from NBS patients point to a deficiency in the repair of DNA double strand breaks. Here, we review the current knowledge of the role of NBS1 in the DNA damage response. Emphasis is placed on the role of NBS1 in the DNA double strand repair, modulation of the DNA damage sensing and signaling, cell cycle checkpoint control and maintenance oftelomere stability.展开更多
Hepatitis B virus(HBV),one of the well-known DNA oncogenic viruses,is the leading cause of hepatocellular carcinoma(HCC).In infected hepatocytes,HBV DNA can be integrated into the host genome through an insertional mu...Hepatitis B virus(HBV),one of the well-known DNA oncogenic viruses,is the leading cause of hepatocellular carcinoma(HCC).In infected hepatocytes,HBV DNA can be integrated into the host genome through an insertional mutagenesis process inducing tumorigenesis.Dissection of the genomic features surrounding integration sites will deepen our understanding of mechanisms underlying integration.Moreover,the quantity and biological activity of integration sites may reflect the DNA damage within affected cells or the potential survival benefits they may confer.The wellknown human genomic features include repeat elements,particular regions(such as telomeres),and frequently interrupted genes(e.g.,telomerase reverse transcriptase[i.e.TERT],lysine methyltransferase 2B[i.e.KMT2B],cyclin E1[CCNE1],and cyclin A2[CCNA2]).Consequently,distinct genomic features within diverse integrations differentiate their biological functions.Meanwhile,accumulating evidence has shown that viral proteins produced by integrants may cause cell damage even after the suppression of HBV replication.The integration-derived gene products can also serve as tumor markers,promoting the development of novel therapeutic strategies for HCC.Viral integrants can be single copy or multiple copies of different fragments with complicated rearrangement,which warrants elucidation of the whole viral integrant arrangement in future studies.All of these considerations underlie an urgent need to develop novel methodology and technology for sequence characterization and function evaluation of integration events in chronic hepatitis B-associated disease progression by monitoring both host genomic features and viral integrants.This endeavor may also serve as a promising solution for evaluating the risk of tumorigenesis and as a companion diagnostic for designing therapeutic strategies targeting integration-related disease complications.展开更多
The CRISPR/Cas9 technology is evolved from a type II bacterial immune system and represents a new generation of targeted genome editing technology that can be applied to nearly all organisms. Site-specific modificatio...The CRISPR/Cas9 technology is evolved from a type II bacterial immune system and represents a new generation of targeted genome editing technology that can be applied to nearly all organisms. Site-specific modification is achieved by a single guide RNA(usually about 20nucleotides) that is complementary to a target gene or locus and is anchored by a protospaceradjacent motif. Cas9 nuclease then cleaves the targeted DNA to generate double-strand breaks(DSBs), which are subsequently repaired by non-homologous end joining(NHEJ) or homology-directed repair(HDR) mechanisms. NHEJ may introduce indels that cause frame shift mutations and hence the disruption of gene functions. When combined with double or multiplex guide RNA design, NHEJ may also introduce targeted chromosome deletions,whereas HDR can be engineered for target gene correction, gene replacement, and gene knock-in. In this review, we briefly survey the history of the CRISPR/Cas9 system invention and its genome-editing mechanism. We also describe the most recent innovation of the CRISPR/Cas9 technology, particularly the broad applications of modified Cas9 variants, and discuss the potential of this system for targeted genome editing and modification for crop improvement.展开更多
RecQ5 in mammalian cells has been suggested to suppress inappropriate homologous recombination.However,the specific pathway(s)in which it is involved and the underlining mechanism(s)remain poorly understood.We took ad...RecQ5 in mammalian cells has been suggested to suppress inappropriate homologous recombination.However,the specific pathway(s)in which it is involved and the underlining mechanism(s)remain poorly understood.We took advantage of genetic tools in Drosophila to investigate how Drosophila RecQ5(dRecQ5)functions in vivo in homologous recombination-mediated double strand break(DSB)repair.We generated null alleles of dRecQ5 using the targeted recombination technique.The mutant animals are homozygous viable,but with growth retardation during development.The mutants are sensitive to both exogenous DSB-inducing treatment,such as gamma-irradiation,and endogenously induced double strand breaks(DSBs)by I-Sce I endonuclease.In the absence of dRecQ5,single strand annealing(SSA)-mediated DSB repair is compromised with compensatory increases in either inter-homologous gene conversion,or non-homologous end joining(NHEJ)when inter-chromosomal homologous sequence is unavailable.Loss of function of dRecQ5 also leads to genome instability in loss of heterozygosity(LOH)assays.Together,our data demonstrate that dRecQ5 functions in SSA-mediated DSB repair to achieve its full efficiency and in suppression of LOH in Drosophila.展开更多
Site-specific recognition modules with DNA nuclease have tremendous potential as molecular tools for genome targeting. The type III transcription activator-like effectors （TALEs） contain a DNA binding domain consist...Site-specific recognition modules with DNA nuclease have tremendous potential as molecular tools for genome targeting. The type III transcription activator-like effectors （TALEs） contain a DNA binding domain consisting of tandem repeats that can be engineered to bind user-defined specific DNA sequences. We demonstrated that customized TALE-based nucleases （TALENs）, constructed using a method called ＂unit assembly＂, specifically target the endogenous FRIGIDA gene in Brassica oleracea L. var. capitata L. The results indicate that the TALENs bound to the target site and cleaved double-strand DNA in vitro and in vivo, whereas the effector binding elements have a 23 bp spacer. The T7 endonuclease I assay and sequencing data show that TALENs made double-strand breaks, which were repaired by a non- homologous end-joining pathway within the target sequence. These data show the feasibility of applying customized TALENs to target and modify the genome with deletions in those organisms that are still in lacking gene target methods to provide germplasms in breeding improvement.展开更多
The hematopoietic system is susceptible to ionizing radiation(IR),which can cause acute hematopoietic failure or long-term myelosuppression.As the most primitive cells of the hematopoietic hierarchy,hematopoietic stem...The hematopoietic system is susceptible to ionizing radiation(IR),which can cause acute hematopoietic failure or long-term myelosuppression.As the most primitive cells of the hematopoietic hierarchy,hematopoietic stem cells(HSCs)maintain lifelong hematopoietic homeostasis and promote hematopoietic regeneration during stress.Numerous studies have shown that nuclear and mitochondrial genomes are the main targets of radiation injury in HSCs.More importantly,the damage of DNA may trigger a series of biological responses that largely determine HSC fate following IR exposure.Although some essential pathways and factors involved in DNA injury and damage in HSCs have been revealed,a comprehensive understanding of the biological effects of radiation on HSCs still needs to be improved.This review focuses on recent insights into the molecular mechanisms underlying DNA damage and repair in HSCs after IR.Then summarize corresponding regulatory measures,which may provide a reference for further research in this field.展开更多
Fast neutrons have sufficient energy to liberate recoil protons,alpha particles,and other products when they interact with the nuclei of the target material through scattering and absorption processes.Physical interac...Fast neutrons have sufficient energy to liberate recoil protons,alpha particles,and other products when they interact with the nuclei of the target material through scattering and absorption processes.Physical interactions with biological tissues occur mainly with hydrogen nuclei and as the protons interact with the hydrogen in tissues,they create dense ionization chains along their tracks thus depositing energy.Fast neutron therapy was pioneered by Robert Stone in 1938 a few years after the discovery of the neutron.Its main advantage is the limited sensitivity to hypoxia and treatment of slow-growing tumors hence better local control.This is where photon therapy has yet to have much success.Energy deposition by fast neutrons in living tissues is higher than in conventional radiotherapy using mega voltage(MV)photon beams.This higher energy deposition gives fast neutrons a higher relative biological effectiveness(RBE)in dealing with certain tumors.Fast neutrons also have a higher linear energy transfer(LET)and can reach deep-sited tumors better than photon therapy.The main challenge with Fast neutron therapy has been extreme toxicity in late-reacting tissues.Overall,fast neutron therapy holds potential for the treatment of certain tumors by leveraging the unique interaction characteristics of fast neutrons with biological tissues.This review therefore intends to bring this uniqueness to light to enhance the understanding of the radiobiological properties of fast neutrons and the advantages associated with its therapy.展开更多
More than half of cancer patients are treated with radiotherapy,which kills tumor cells by directly and indirectly inducing DNA damage,including cytotoxic DNA double-strand breaks(DSBs).Tumor cells respond to these th...More than half of cancer patients are treated with radiotherapy,which kills tumor cells by directly and indirectly inducing DNA damage,including cytotoxic DNA double-strand breaks(DSBs).Tumor cells respond to these threats by activating a complex signaling network termed the DNA damage response(DDR).The DDR arrests the cell cycle,upregulates DNA repair,and triggers apoptosis when damage is excessive.The DDR signaling and DNA repair pathways are fertile terrain for therapeutic intervention.This review highlights strategies to improve therapeutic gain by targeting DDR and DNA repair pathways to radiosensitize tumor cells,overcome intrinsic and acquired tumor radioresistance,and protect normal tissue.Many biological and environmental factors determine tumor and normal cell responses to ionizing radiation and genotoxic chemotherapeutics.These include cell type and cell cycle phase distribution;tissue/tumor microenvironment and oxygen levels;DNA damage load and quality;DNA repair capacity;and susceptibility to apoptosis or other active or passive cell death pathways.We provide an overview of radiobiological parameters associated with X-ray,proton,and carbon ion radiotherapy;DNA repair and DNA damage signaling pathways;and other factors that regulate tumor and normal cell responses to radiation.We then focus on recent studies exploiting DSB repair pathways to enhance radiotherapy therapeutic gain.展开更多
Maintenance of cellular homeostasis and genome integrity is a critical responsibility of DNA double-strand break(DSB)signaling.P53-binding protein 1(53BP1)plays a critical role in coordinating the DSB repair pathway c...Maintenance of cellular homeostasis and genome integrity is a critical responsibility of DNA double-strand break(DSB)signaling.P53-binding protein 1(53BP1)plays a critical role in coordinating the DSB repair pathway choice and promotes the non-homologous end-joining(NHEJ)-mediated DSB repair pathway that rejoins DSB ends.New insights have been gained into a basic molecular mechanism that is involved in 53BP1 recruitment to the DNA lesion and how 53BP1 then recruits the DNA break-responsive effectors that promote NHEJ-mediated DSB repair while inhibiting homologous recombination(HR)signaling.This review focuses on the up-and downstream pathways of 53BP1 and how 53BP1 promotes NHEJ-mediated DSB repair,which in turn promotes the sensitivity of poly(ADP-ribose)polymerase inhibitor(PARPi)in BRCA1-deficient cancers and consequently provides an avenue for improving cancer therapy strategies.展开更多
The clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)is widely used for targeted genomic and epigenomic modifications and imaging in cells and organisms,and holds trem...The clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)is widely used for targeted genomic and epigenomic modifications and imaging in cells and organisms,and holds tremendous promise in clinical applications.The efficiency and accuracy of the technology are partly determined by the target binding affinity and residence time of Cas9-single-guide RNA(sgRNA)at a given site.However,little attention has been paid to the effect of target binding affinity and residence duration on the repair of Cas9-induced DNA double-strand breaks(DSBs).We propose that the choice of DSB repair pathway may be altered by variation in the binding affinity and residence duration of Cas9-sgRNA at the cleaved target,contributing to significantly heterogeneous mutations in CRISPR/Cas9 genome editing.Here,we discuss the effect of Cas9-sgRNA target binding and residence on the choice of DSB repair pathway in CRISPR/Cas9 genome editing,and the opportunity this presents to optimize Cas9-based technology.展开更多
Meiosis is an essential step in gametogenesis which is the key process in sexually reproducing organisms as meiotic aberrations may result in infertility. In meiosis, programmed DNA double-strand break (DSB) formation...Meiosis is an essential step in gametogenesis which is the key process in sexually reproducing organisms as meiotic aberrations may result in infertility. In meiosis, programmed DNA double-strand break (DSB) formation is one of the fundamental processes that are essential for maintaining homolog interactions and correcting segregation of chromosomes. Although the number and distribution of meiotic DSBs are tightly regulated, still abnormalities in DSB formation are known to cause meiotic arrest and infertility. This review is a detailed account of molecular bases of meiotic DSB formation, its evolutionary conservation, and variations in different species. We further reviewed the mutations of DSB formation genes in association with human infertility and also proposed the future directions and strategies about the study of meiotic DSB formation.展开更多
文摘DNA double-strand breaks （DSBs） are introduced in cells by ionizing radiation and reactive oxygen species. In addition, they are commonly generated during V（D）J recombination, an essential aspect of the developing immune system. Failure to effectively repair these DSBs can result in chromosome breakage, cell death, onset of cancer, and defects in the immune system of higher vertebrates. Fortunately, all mammalian cells possess two enzymatic pathways that mediate the repair of DSBs： homologous recombination and non-homologous end-joining （NHEJ）. The NHEJ process utilizes enzymes that capture both ends of the broken DNA molecule, bring them together in a synaptic DNA-protein complex, and finally repair the DNA break. In this review, all the known enzymes that play a role in the NHEJ process are discussed and a working model for the co-operation of these enzymes during DSB repair is presented.
文摘The genomes of eukaryotic cells are under continuous assault by environmental agents and endogenous metabolic byproducts. Damage induced in DNA usually leads to a cascade of cellular events, the DNA damage response. Failure of the DNA damage response can lead to development of malignancy by reducing the efficiency and fidelity of DNA repair. The NBS1 protein is a component of the MRE11/RAD50/NBS 1 complex （MRN） that plays a critical role in the cellular response to DNA damage and the maintenance of chromosomal integrity. Mutations in the NBS1 gene are responsible for Nijmegen breakage syndrome （NBS）, a hereditary disorder that imparts an increased predisposition to development of malignancy. The phenotypic characteristics of cells isolated from NBS patients point to a deficiency in the repair of DNA double strand breaks. Here, we review the current knowledge of the role of NBS1 in the DNA damage response. Emphasis is placed on the role of NBS1 in the DNA double strand repair, modulation of the DNA damage sensing and signaling, cell cycle checkpoint control and maintenance oftelomere stability.
基金This work was supported by the 111Project(Project No.:B13003)Innovation Promotion Association CAS(2016098)National Natural Science Foundation of China(81201700)to D.Z。
文摘Hepatitis B virus(HBV),one of the well-known DNA oncogenic viruses,is the leading cause of hepatocellular carcinoma(HCC).In infected hepatocytes,HBV DNA can be integrated into the host genome through an insertional mutagenesis process inducing tumorigenesis.Dissection of the genomic features surrounding integration sites will deepen our understanding of mechanisms underlying integration.Moreover,the quantity and biological activity of integration sites may reflect the DNA damage within affected cells or the potential survival benefits they may confer.The wellknown human genomic features include repeat elements,particular regions(such as telomeres),and frequently interrupted genes(e.g.,telomerase reverse transcriptase[i.e.TERT],lysine methyltransferase 2B[i.e.KMT2B],cyclin E1[CCNE1],and cyclin A2[CCNA2]).Consequently,distinct genomic features within diverse integrations differentiate their biological functions.Meanwhile,accumulating evidence has shown that viral proteins produced by integrants may cause cell damage even after the suppression of HBV replication.The integration-derived gene products can also serve as tumor markers,promoting the development of novel therapeutic strategies for HCC.Viral integrants can be single copy or multiple copies of different fragments with complicated rearrangement,which warrants elucidation of the whole viral integrant arrangement in future studies.All of these considerations underlie an urgent need to develop novel methodology and technology for sequence characterization and function evaluation of integration events in chronic hepatitis B-associated disease progression by monitoring both host genomic features and viral integrants.This endeavor may also serve as a promising solution for evaluating the risk of tumorigenesis and as a companion diagnostic for designing therapeutic strategies targeting integration-related disease complications.
基金supported in part by the Key Transgenic Breeding Program of the Ministry of Agriculture of China(ZX2014X08009-001 and ZX2016X08009-001)the Agricultural Science and Technology Innovation Program of CAAS
文摘The CRISPR/Cas9 technology is evolved from a type II bacterial immune system and represents a new generation of targeted genome editing technology that can be applied to nearly all organisms. Site-specific modification is achieved by a single guide RNA(usually about 20nucleotides) that is complementary to a target gene or locus and is anchored by a protospaceradjacent motif. Cas9 nuclease then cleaves the targeted DNA to generate double-strand breaks(DSBs), which are subsequently repaired by non-homologous end joining(NHEJ) or homology-directed repair(HDR) mechanisms. NHEJ may introduce indels that cause frame shift mutations and hence the disruption of gene functions. When combined with double or multiplex guide RNA design, NHEJ may also introduce targeted chromosome deletions,whereas HDR can be engineered for target gene correction, gene replacement, and gene knock-in. In this review, we briefly survey the history of the CRISPR/Cas9 system invention and its genome-editing mechanism. We also describe the most recent innovation of the CRISPR/Cas9 technology, particularly the broad applications of modified Cas9 variants, and discuss the potential of this system for targeted genome editing and modification for crop improvement.
基金This work has been financially supported by the National Basic Research Program(973 Program)(Nos.2009CB918702,2005CB522804)the National Natural Science Foundation of China(Grant Nos.30623005,90608029 and 30771217)Chinese Academy of Sciences(KSCX1-YW-R-70).
文摘RecQ5 in mammalian cells has been suggested to suppress inappropriate homologous recombination.However,the specific pathway(s)in which it is involved and the underlining mechanism(s)remain poorly understood.We took advantage of genetic tools in Drosophila to investigate how Drosophila RecQ5(dRecQ5)functions in vivo in homologous recombination-mediated double strand break(DSB)repair.We generated null alleles of dRecQ5 using the targeted recombination technique.The mutant animals are homozygous viable,but with growth retardation during development.The mutants are sensitive to both exogenous DSB-inducing treatment,such as gamma-irradiation,and endogenously induced double strand breaks(DSBs)by I-Sce I endonuclease.In the absence of dRecQ5,single strand annealing(SSA)-mediated DSB repair is compromised with compensatory increases in either inter-homologous gene conversion,or non-homologous end joining(NHEJ)when inter-chromosomal homologous sequence is unavailable.Loss of function of dRecQ5 also leads to genome instability in loss of heterozygosity(LOH)assays.Together,our data demonstrate that dRecQ5 functions in SSA-mediated DSB repair to achieve its full efficiency and in suppression of LOH in Drosophila.
基金supported by grants from the National Basic Research Program of China (973 program, 2012CB113900)the National Natural Science Foundation of China (31071802)the Chongqing Natural Science Foundation (2011BA1002)
文摘Site-specific recognition modules with DNA nuclease have tremendous potential as molecular tools for genome targeting. The type III transcription activator-like effectors （TALEs） contain a DNA binding domain consisting of tandem repeats that can be engineered to bind user-defined specific DNA sequences. We demonstrated that customized TALE-based nucleases （TALENs）, constructed using a method called ＂unit assembly＂, specifically target the endogenous FRIGIDA gene in Brassica oleracea L. var. capitata L. The results indicate that the TALENs bound to the target site and cleaved double-strand DNA in vitro and in vivo, whereas the effector binding elements have a 23 bp spacer. The T7 endonuclease I assay and sequencing data show that TALENs made double-strand breaks, which were repaired by a non- homologous end-joining pathway within the target sequence. These data show the feasibility of applying customized TALENs to target and modify the genome with deletions in those organisms that are still in lacking gene target methods to provide germplasms in breeding improvement.
基金supported by National Natural Science Foundation of China(No.81930090,82203974)Natural Science Foundation of Chongqing City,China(No.CSTB2023NSCQ-MSX0284)+2 种基金Postdoctoral Innovative Talent Support Program of China(No.BX20220398)China Postdoctoral Science Foundation(No.2022M723867)Postdoctoral Innovative Talent Support Program of Chongqing,(No.CQBX2021017)China.
文摘The hematopoietic system is susceptible to ionizing radiation(IR),which can cause acute hematopoietic failure or long-term myelosuppression.As the most primitive cells of the hematopoietic hierarchy,hematopoietic stem cells(HSCs)maintain lifelong hematopoietic homeostasis and promote hematopoietic regeneration during stress.Numerous studies have shown that nuclear and mitochondrial genomes are the main targets of radiation injury in HSCs.More importantly,the damage of DNA may trigger a series of biological responses that largely determine HSC fate following IR exposure.Although some essential pathways and factors involved in DNA injury and damage in HSCs have been revealed,a comprehensive understanding of the biological effects of radiation on HSCs still needs to be improved.This review focuses on recent insights into the molecular mechanisms underlying DNA damage and repair in HSCs after IR.Then summarize corresponding regulatory measures,which may provide a reference for further research in this field.
文摘Fast neutrons have sufficient energy to liberate recoil protons,alpha particles,and other products when they interact with the nuclei of the target material through scattering and absorption processes.Physical interactions with biological tissues occur mainly with hydrogen nuclei and as the protons interact with the hydrogen in tissues,they create dense ionization chains along their tracks thus depositing energy.Fast neutron therapy was pioneered by Robert Stone in 1938 a few years after the discovery of the neutron.Its main advantage is the limited sensitivity to hypoxia and treatment of slow-growing tumors hence better local control.This is where photon therapy has yet to have much success.Energy deposition by fast neutrons in living tissues is higher than in conventional radiotherapy using mega voltage(MV)photon beams.This higher energy deposition gives fast neutrons a higher relative biological effectiveness(RBE)in dealing with certain tumors.Fast neutrons also have a higher linear energy transfer(LET)and can reach deep-sited tumors better than photon therapy.The main challenge with Fast neutron therapy has been extreme toxicity in late-reacting tissues.Overall,fast neutron therapy holds potential for the treatment of certain tumors by leveraging the unique interaction characteristics of fast neutrons with biological tissues.This review therefore intends to bring this uniqueness to light to enhance the understanding of the radiobiological properties of fast neutrons and the advantages associated with its therapy.
文摘More than half of cancer patients are treated with radiotherapy,which kills tumor cells by directly and indirectly inducing DNA damage,including cytotoxic DNA double-strand breaks(DSBs).Tumor cells respond to these threats by activating a complex signaling network termed the DNA damage response(DDR).The DDR arrests the cell cycle,upregulates DNA repair,and triggers apoptosis when damage is excessive.The DDR signaling and DNA repair pathways are fertile terrain for therapeutic intervention.This review highlights strategies to improve therapeutic gain by targeting DDR and DNA repair pathways to radiosensitize tumor cells,overcome intrinsic and acquired tumor radioresistance,and protect normal tissue.Many biological and environmental factors determine tumor and normal cell responses to ionizing radiation and genotoxic chemotherapeutics.These include cell type and cell cycle phase distribution;tissue/tumor microenvironment and oxygen levels;DNA damage load and quality;DNA repair capacity;and susceptibility to apoptosis or other active or passive cell death pathways.We provide an overview of radiobiological parameters associated with X-ray,proton,and carbon ion radiotherapy;DNA repair and DNA damage signaling pathways;and other factors that regulate tumor and normal cell responses to radiation.We then focus on recent studies exploiting DSB repair pathways to enhance radiotherapy therapeutic gain.
文摘Maintenance of cellular homeostasis and genome integrity is a critical responsibility of DNA double-strand break(DSB)signaling.P53-binding protein 1(53BP1)plays a critical role in coordinating the DSB repair pathway choice and promotes the non-homologous end-joining(NHEJ)-mediated DSB repair pathway that rejoins DSB ends.New insights have been gained into a basic molecular mechanism that is involved in 53BP1 recruitment to the DNA lesion and how 53BP1 then recruits the DNA break-responsive effectors that promote NHEJ-mediated DSB repair while inhibiting homologous recombination(HR)signaling.This review focuses on the up-and downstream pathways of 53BP1 and how 53BP1 promotes NHEJ-mediated DSB repair,which in turn promotes the sensitivity of poly(ADP-ribose)polymerase inhibitor(PARPi)in BRCA1-deficient cancers and consequently provides an avenue for improving cancer therapy strategies.
基金supported by the National Natural Science Foundation of China(Nos.31671385 and 31870806)the Zhejiang Provincial Natural Science Foundation of China(Nos.LY18C050001 and LQ20C050004)the Fundamental Research Funds for the Central Universities in China(No.2019QNA7031)。
文摘The clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)is widely used for targeted genomic and epigenomic modifications and imaging in cells and organisms,and holds tremendous promise in clinical applications.The efficiency and accuracy of the technology are partly determined by the target binding affinity and residence time of Cas9-single-guide RNA(sgRNA)at a given site.However,little attention has been paid to the effect of target binding affinity and residence duration on the repair of Cas9-induced DNA double-strand breaks(DSBs).We propose that the choice of DSB repair pathway may be altered by variation in the binding affinity and residence duration of Cas9-sgRNA at the cleaved target,contributing to significantly heterogeneous mutations in CRISPR/Cas9 genome editing.Here,we discuss the effect of Cas9-sgRNA target binding and residence on the choice of DSB repair pathway in CRISPR/Cas9 genome editing,and the opportunity this presents to optimize Cas9-based technology.
基金This work was supported by the National Key Research and Developmental Program of China(2018YFC1003700,2018YFC1003400,and 2016YFC1000600)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB19000000)+1 种基金the National Natural Science Foundation of China(31890780,31630050,32061143006,82071709,and 31871514)the Fundamental Research Funds for the Central Universities(YD2070002006).
文摘Meiosis is an essential step in gametogenesis which is the key process in sexually reproducing organisms as meiotic aberrations may result in infertility. In meiosis, programmed DNA double-strand break (DSB) formation is one of the fundamental processes that are essential for maintaining homolog interactions and correcting segregation of chromosomes. Although the number and distribution of meiotic DSBs are tightly regulated, still abnormalities in DSB formation are known to cause meiotic arrest and infertility. This review is a detailed account of molecular bases of meiotic DSB formation, its evolutionary conservation, and variations in different species. We further reviewed the mutations of DSB formation genes in association with human infertility and also proposed the future directions and strategies about the study of meiotic DSB formation.
