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
目的:对珊瑚菜(Glehnia littoralis)4-香豆酸:辅酸A连接酶(4-Coumarate:Coenzyme A Ligase,Gl4CL)基因编码区进行克隆及序列分析。方法:本研究在前期珊瑚菜高通量测序的基础上,利用c DNA末端快速扩增(Rapid Amplification of c DNA Ends...目的:对珊瑚菜(Glehnia littoralis)4-香豆酸:辅酸A连接酶(4-Coumarate:Coenzyme A Ligase,Gl4CL)基因编码区进行克隆及序列分析。方法:本研究在前期珊瑚菜高通量测序的基础上,利用c DNA末端快速扩增(Rapid Amplification of c DNA Ends,RACE)方法对Gl4CL基因全长c DNA序列进行克隆。对Gl4CL蛋白进行理化性质、蛋白二级结构及三维结构预测分析。利用实时荧光定量PCR方法检测Gl4CL基因在珊瑚菜的根、叶中的表达情况。结果:Gl4CL基因cDNA序列全长1 951 bp,编码544个氨基酸,其中开放阅读框1 635 bp,5′非编码区153 bp,3′非编码区163 bp。生物信息学分析表明,Gl4CL蛋白大小约为59.481 k Da,等电点为8.20。Gl4CL基因在珊瑚菜的根和叶均存在表达,且在根中表达量显著高于叶。结论:本研究为进一步开展Gl4CL基因功能和遗传调控研究奠定基础,通过深入探讨Gl4CL基因的表达调控与木质素、植株生长表型等关系,有望获得抗病虫害、抗逆性强的北沙参高产优质品系。展开更多
Protein modification by small ubiquitin-like modifier(SUMO)is an important regulatory mechanism for multiple cellular pro-cesses.Although the canonical pathway involving the ubiquitylation or phosphorylation of IκBα...Protein modification by small ubiquitin-like modifier(SUMO)is an important regulatory mechanism for multiple cellular pro-cesses.Although the canonical pathway involving the ubiquitylation or phosphorylation of IκBα has been well characterized,little is known about the sumoylation of IkBa in the control of NF-κB activity.Here,we find that histone deacetylase 4(HDAC4)negatively regulates tumor necrosis factor-alpha-or lipopolysaccharide-triggered NF-κB activation.HDAC4 belongs to the SUMO E3 ligase family and can directly sumoylate IκBα.The cytoplasm location of HDAC4 is essential for IκBαsumoylation.The Cys292 of HDAC4 is a key site for its SUMO E3 ligase activity.The sumoylation of IkBc prevents its polyubiquitination and degradation be-cause these two modifications occur both at the Lys21.Our findings reveal a previously undiscovered role for HDAC4 in the inflammatory response as a SUMO E3 ligase for IκBαsumoylation.Our work provides insight into mechanisms ensuring optimal mediation of the NF-κB pathway.展开更多
DNA double-strand breaks(DSBs)are one of the most lethal forms of DNA damage that is not efficiently repaired in prokaryotes.Certain microorganisms can handle chromosomal DSBs using the error-prone non-homologous end ...DNA double-strand breaks(DSBs)are one of the most lethal forms of DNA damage that is not efficiently repaired in prokaryotes.Certain microorganisms can handle chromosomal DSBs using the error-prone non-homologous end joining(NHEJ)system and ultimately cause genome mutagenesis.Here,we demonstrated that Enterobacteria phage T4 DNA ligase alone is capable of mediating in vivo chromosome DSBs repair in Escherichia coli.The ligation efficiency of DSBs with T4 DNA ligase is one order of magnitude higher than the NHEJ system from Mycobacterium tuberculosis.This process introduces chromosome DNA excision with different sizes,which can be manipulated by regulating the activity of host-exonuclease RecBCD.The DNA deletion length reduced either by inactivating recB or expressing the RecBCD inhibitor Gam protein fromλphage.Furthermore,we also found single nucleotide substitutions at the DNA junction,suggesting that T4 DNA ligase,as a single component non-homologous end joining system,has great potential in genome mutagenesis,genome reduction and genome editing.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.
基金Foundation item:The National Basic Research Program of China(grant numbers 2010CB126306&2012CB944504)the National Science Fund for Excellent Young Scholars of NSFC(grant number 31222052)the FEBL grant 2011FBZ23
文摘目的:对珊瑚菜(Glehnia littoralis)4-香豆酸:辅酸A连接酶(4-Coumarate:Coenzyme A Ligase,Gl4CL)基因编码区进行克隆及序列分析。方法:本研究在前期珊瑚菜高通量测序的基础上,利用c DNA末端快速扩增(Rapid Amplification of c DNA Ends,RACE)方法对Gl4CL基因全长c DNA序列进行克隆。对Gl4CL蛋白进行理化性质、蛋白二级结构及三维结构预测分析。利用实时荧光定量PCR方法检测Gl4CL基因在珊瑚菜的根、叶中的表达情况。结果:Gl4CL基因cDNA序列全长1 951 bp,编码544个氨基酸,其中开放阅读框1 635 bp,5′非编码区153 bp,3′非编码区163 bp。生物信息学分析表明,Gl4CL蛋白大小约为59.481 k Da,等电点为8.20。Gl4CL基因在珊瑚菜的根和叶均存在表达,且在根中表达量显著高于叶。结论:本研究为进一步开展Gl4CL基因功能和遗传调控研究奠定基础,通过深入探讨Gl4CL基因的表达调控与木质素、植株生长表型等关系,有望获得抗病虫害、抗逆性强的北沙参高产优质品系。
基金This study was supported by the National Key Research and Development Program of China(2018YFA0507201 to X.C.and 2018YFA0507202 to Y.Z.)the Program for Youth Innovation Promotion Association in Chinese Academy of Sciences to J.C.the China Postdoctoral Science Foundation(2020M672580 to Q.Y).
文摘Protein modification by small ubiquitin-like modifier(SUMO)is an important regulatory mechanism for multiple cellular pro-cesses.Although the canonical pathway involving the ubiquitylation or phosphorylation of IκBα has been well characterized,little is known about the sumoylation of IkBa in the control of NF-κB activity.Here,we find that histone deacetylase 4(HDAC4)negatively regulates tumor necrosis factor-alpha-or lipopolysaccharide-triggered NF-κB activation.HDAC4 belongs to the SUMO E3 ligase family and can directly sumoylate IκBα.The cytoplasm location of HDAC4 is essential for IκBαsumoylation.The Cys292 of HDAC4 is a key site for its SUMO E3 ligase activity.The sumoylation of IkBc prevents its polyubiquitination and degradation be-cause these two modifications occur both at the Lys21.Our findings reveal a previously undiscovered role for HDAC4 in the inflammatory response as a SUMO E3 ligase for IκBαsumoylation.Our work provides insight into mechanisms ensuring optimal mediation of the NF-κB pathway.
基金This work was supported by grants from the National Natural Science Foundation of China[31730003,31670077]Natural Science Foundation of Shandong Province[ZR2017ZB0210].
文摘DNA double-strand breaks(DSBs)are one of the most lethal forms of DNA damage that is not efficiently repaired in prokaryotes.Certain microorganisms can handle chromosomal DSBs using the error-prone non-homologous end joining(NHEJ)system and ultimately cause genome mutagenesis.Here,we demonstrated that Enterobacteria phage T4 DNA ligase alone is capable of mediating in vivo chromosome DSBs repair in Escherichia coli.The ligation efficiency of DSBs with T4 DNA ligase is one order of magnitude higher than the NHEJ system from Mycobacterium tuberculosis.This process introduces chromosome DNA excision with different sizes,which can be manipulated by regulating the activity of host-exonuclease RecBCD.The DNA deletion length reduced either by inactivating recB or expressing the RecBCD inhibitor Gam protein fromλphage.Furthermore,we also found single nucleotide substitutions at the DNA junction,suggesting that T4 DNA ligase,as a single component non-homologous end joining system,has great potential in genome mutagenesis,genome reduction and genome editing.
