表观遗传修饰新发现

,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Critical roles of,DNA dmethylation,in the activation of ripening-induced genes and inhibition of ripening-repressed genes in tomoto fruit,PNAS,Published online May 15,2017,1,郝雪峰,1.Abstract,DNA methylation,is a conserved epigenetic mark important for genome integrity,development,and environmental responses in plants and mammals.,Active DNA demethylaton,in plants is initiated by a family of 5-mC DNA glycosylases/lyases(i.e.,DNA demethylases).,This study suggests,that active DNA demethylation is required for both the,activation,of ripening-induced genes and the,inhibition,of ripening-repressed genes.,2,2.1 Research Background,Cytosine methylation levels&gene activation,5-mC levels,are dynamically regulated by,methylation,and,demethylation,reactions.,DNA methylation,is generally associated with,inactive transcription,.,Active DNA demethylation,is critical for,gene activation,or for,the prevention of silencing,.,DNA methylation site:,In mammals:CG,（,DNMTs,）,In plants:CG,（,MET1,）,/CHH,（,CMT2,DRM2,）,/CNG,（,CMT3,）,3,4,2.2 Research Background,ROS1 preferentially targets TEs,TEs,（,Transposable Elements,）,When ROS1 targeted TEs are located in the promoter regions of genes,ROS1 can,protect gene expression,by demethylating the adjacent TE,s,.,Many studies have demonstrated that,by demethylating nearby TEs,active DNA demethylation is critical for,gene activation,or for the,prevention of silencing,.,2.3 Research Background,In contrast to,Arabidopsis,Tomato,is an economically,important crop,and a,model,for studying fleshy fruit ripening,.,Fruit ripening is associated with many distinct changes,which are driven by,phytohormones,and,developmental factors,.,In addition to,ethylene,and the,TFs,DNA methylation,is another key regulator of fruit ripening.,5,2.4 Research Background,Tomato contains four putative DNA demethylases:,SlDML 1,4,SlDML 1/2,：,most closely related to,AtROS1,SlDMLs play critical roles in fruit ripening.,RNAi against the conserved HhH-GPD domain,Which,SlDML(s)is required for fruit ripening?,What impact,dose active DNA demethylation have on the genome-wide during fruit ripening?,6,3.Research Contents,Generated,two,mutant,alleles of SlDML2.,in the tomato cultivar Micro-Tom,using CRISPR/Cas 9 system,Determined,the,genome-wide effect,of SlDML2 on DNA demethylation.,compared the DNA methylomes of WT and,sidml2,mutant fruits;,Analyzed,the,transcriptome,of,sidml2,mutant fruits.,4.Result,4.1 Generation of stable,loss-of-function mutant alleles of,SlDML2,using the CRISPR/Cas9 gene-editing system.,8,4.Result,4.2 The,sldml2,mutations inhibit fruit ripening.,9,4.Result,4.3,The,sldml2,mutations cause genome-wide DNA hypermethylation.,W,hole-genome bisulfite sequencing,was performed,to i,nvestigate the genetic function of SlDML2,in DNA demethylation during fruit ripening,.,单个碱基,被测序的,平均次数,测序获得的序列,占,整个基因组,的比例,The results is consistent with the presumed function of SlDML2 in DNA demethylaton.,Differentially methylated regions,11,(A).DNA methylation,levels of,sldml2-1,hyper-DMRs,in fruits at 46 dpa.,(B).Boxplots showing,DNA methylation levels,at combined hyper-DMRs.,DNA methylation levels of several,sldml2,hyper-DMRs(boxed regions)in WT and,sldml2,.,13,(A)The,compositions of hyer-DMRs,.(B),Density plots,of 1,5,.,14,Chromosomal distribution of,SlDML2-targeted TEs,and,total TEs,.,(C).,Boxplots showing distances between SIDML2-targeted or nontargeted TE(Left)and IG regions(Right)and their nearest protein-coding genes.,(D).,Boxplot showing the distances between genes and their nearest TEs in Arabidopsis and tomato.,(E).,Percentages of genes that contain TEs in their 500-bp,1000-bp,and 2000-bp upstream sequences in Arabidopsis,tomato,maize,and rice.,15,(C)Boxplots showing distances between SIDML2-targeted or nontargeted TE(Left)and IG regions(Right),and their nearest protein-coding genes.,(D)Boxplot showing t