We report the genome-wide analysis of direct target genes of SND1 and VND7, two Arabidopsis thaliana NAC domain transcription factors that are master regulators of secondary wall biosynthesis in fibers and vessels, re...We report the genome-wide analysis of direct target genes of SND1 and VND7, two Arabidopsis thaliana NAC domain transcription factors that are master regulators of secondary wall biosynthesis in fibers and vessels, respectively. Systematic mapping of the SND1 binding sequence using electrophoretic mobility shift assay and transactivation analysis demonstrated that SND1 together with other secondary wall NACs （SWNs）, including VND6, VND7, NST1, and NST2, bind to an imperfect palindromic 19-bp consensus sequence designated as secondary wall NAC binding element （SNBE）, （T/A）NN（C/T） （TICIG）TNNNNNNNA（AIC）GN（AJCIT） （A/T）, in the promoters of their direct targets. Genome-wide analysis of direct targets of SND1 and VND7 revealed that they directly activate the expression of not only downstream transcription factors, but also a number of non-transcription factor genes involved in secondary wall biosynthesis, cell wall modification, and programmed cell death, the promoters of which all contain multiple SNBE sites. SND1 and VND7 directly regulate the expression of a set of common targets but each of them also preferentially induces a distinct set of direct targets, which is likely attributed to their differential activation strength toward SNBE sites. Complementation study showed that the SWNs were able to rescue the secondary wall defect in the sndl nstl mutant, indicating that they are functionally interchangeable. Together, our results provide important insight into the complex transcriptional program and the evolutionary mechanism underlying secondary wall biosynthesis, cell wall modification, and programmed cell death in secondary wall-containing cell types.展开更多
NAC proteins are plant-specific transcription factors and enriched with members involved in plant response to drought stress. In this study, we analyzed the expression profiles of TaNAC69 in bread wheat using Affymetr...NAC proteins are plant-specific transcription factors and enriched with members involved in plant response to drought stress. In this study, we analyzed the expression profiles of TaNAC69 in bread wheat using Affymetrix Wheat Genome Array datasets and quantitative RT-PCR. TaNAC69 expression was positively associated with wheat responses to both abiotic and biotic stresses and was closely correlated with a number of stress up-regulated genes. The functional analyses of TaNAC69 in transgenic wheat showed that TaNAC69 driven by a barley drought-inducible HvDhn4s promoter led to marked drought-inducible overexpression of TaNAC69 in the leaves and roots of transgenic lines. The HvDhn4s：Ta- NAC69 transgenic lines produced more shoot biomass under combined mild salt stress and water-limitation conditions, had longer root and more root biomass under polyethylene glycol-induced dehydration. Analysis of transgenic lines with constitutive overexpression of TaNAC69 showed the enhanced expression levels of several stress up-regulated genes. DNA-binding assays revealed that TaNAC69 and its rice homolog （ONAC131） were capable of binding to the promoter elements of three rice genes （chitinase, ZlM, and glyoxalase I） and an Arabidopsis glyoxalase I family gene, which are homologs of TaNAC69 up-regulated stress genes. These data suggest that TaNAC69 is involved in regulating stress upregulated genes and wheat adaptation to drought stress.展开更多
NAC domain proteins are plant-specific transcription factors known to play diverse roles in various plant developmental processes. In the present study, we performed the first comprehensive study of the NAC gene famil...NAC domain proteins are plant-specific transcription factors known to play diverse roles in various plant developmental processes. In the present study, we performed the first comprehensive study of the NAC gene family in Gossypium raimondii Ulbr., incorporating phylogenetic, chromosomal location, gene structure, conserved motif, and expression profiling analyses. We identified 145 NAC transcription factor （NAC-TF） genes that were phylogenetically clustered into 18 distinct subfamilies. Of these, 127 NAC-TF genes were distributed across the 13 chromosomes, 80 （55%） were preferentially retained duplicates located in both duplicated regions and six were located in triplicated chromosomal regions. The majority of NAC-TF genes showed temporal-, spatial-, and tissue-specific expression patterns based on tran- scriptomic and qRT-PCR analyses. However, the expression patterns of several duplicate genes were partially redundant, suggesting the occurrence of sub-functionalization during their evolution. Based on their genomic organization, we concluded that genomic duplications contributed significantly to the expansion of the NAC-TF gene family in G. raimondii. Comprehensive analysis of their expression profiles could provide novel insights into the functional divergence among members of the NAC gene family in G. raimondii.展开更多
Neoadjuvant chemotherapy followed by surgery （NCS） has not been fully evaluated clinically. Currently, the main regimen of neoadjuvant chemotherapy （NAC） used in NCS includes cisplatin. The antitumor effects of NA...Neoadjuvant chemotherapy followed by surgery （NCS） has not been fully evaluated clinically. Currently, the main regimen of neoadjuvant chemotherapy （NAC） used in NCS includes cisplatin. The antitumor effects of NAC reduce lymph node metastasis and the tumor diameter in patients prior to surgery, and this can reduce the number of high risk patients who require postoperative radiation therapy. Many randomized controlled trials （RCTs） have examined the long-term prognosis of NCS compared to primary surgery, but the utility of NCS remains uncertain. The advent of concurrent chemoradiotherapy （CCRT） has markedly improved the outcome of radiotherapy （RT）, and CCRT is now used as a standard method in many cases of advanced bulky cervical cancer. NCS gives a better treatment outcome than radiation therapy alone, but it is important to verify that NCS gives a similar or better outcome compared to CCRT.展开更多
We report here that ORS1, a previously uncharacterized member of the NAC transcription factor family, controls leaf senescence in Arabidopsis thaliana. Overexpression of ORS1 accelerates senescence in transgenic plant...We report here that ORS1, a previously uncharacterized member of the NAC transcription factor family, controls leaf senescence in Arabidopsis thaliana. Overexpression of ORS1 accelerates senescence in transgenic plants, whereas its inhibition delays it. Genes acting downstream of ORS1 were identified by global expression analysis using transgenic plants producing dexamethasone-inducible ORSl-GR fusion protein. Of the 42 up-regulated genes, 30 （-70%） were pre- viously shown to be up-regulated during age-dependent senescence, We also observed that 32 （-76%） of the ORSl-dependent genes were induced by long-term （4 d）, but not short-term （6 h） salinity stress （150 mM NaCI）. Furthermore, expression of 16 and 24 genes, respectively, was induced after 1 and 5 h of treatment with hydrogen peroxide （H2O2）, a reactive oxygen species known to accumulate during salinity stress. ORS1 itself was found to be rapidly and strongly induced by H2O2 treatment in both leaves and roots. Using in vitro binding site selection, we determined the preferred binding motif of ORS1 and found it to be present in half of the ORSl-dependent genes. ORS1 is a paralog of ORE1/ ANACO92/AtNAC2, a previously reported regulator of leaf senescence. Phylogenetic footprinting revealed evolutionary conservation of the ORS1 and ORE1 promoter sequences in different Brassicaceae species, indicating strong positive selection acting on both genes. We conclude that ORS1, similarly to ORE1, triggers expression of senescence-associated genes through a regulatory network that may involve cross-talk with saltand H2O2-dependent signaling pathways.展开更多
The importance of NAC(named as NAM,ATAF1,2,and CUC2)proteins in plant development,transcription regulation and regulatory pathways involving proteinprotein interactions has been increasingly recognized.We report here ...The importance of NAC(named as NAM,ATAF1,2,and CUC2)proteins in plant development,transcription regulation and regulatory pathways involving proteinprotein interactions has been increasingly recognized.We report here the high resolution crystal structure of SNAC1(stress-responsive NAC)NAC domain at 2.5Å.Although the structure of the SNAC1 NAC domain shares a structural similarity with the reported structure of the ANAC NAC1 domain,some key features,especially relating to two loop regions which potentially take the responsibility for DNA-binding,distinguish the SNAC1 NAC domain from other reported NAC structures.Moreover,the dimerization of the SNAC1 NAC domain is demonstrated by both soluble and crystalline conditions,suggesting this dimeric state should be conserved in this type of NAC family.Additionally,we discuss the possible NAC-DNA binding model according to the structure and reported biological evidences.展开更多
Determining how function evolves following gene duplication is necessary for understanding gene expansion.Transcription factors(TFs)are a class of proteins that regulate gene expression by binding to specific cis-acti...Determining how function evolves following gene duplication is necessary for understanding gene expansion.Transcription factors(TFs)are a class of proteins that regulate gene expression by binding to specific cis-acting elements in the promoters of target genes,subsequently activating or repressing their transcription.In the present study,we systematically examined the functional diversification of the NAC transcription factor(NAC-TFs)family by analyzing their chromosomal location,structure,phylogeny,and expression pattern in Gossypium raimondii(Gr)and G.arboreum(Ga).The 145 and 141 NAC genes identified in the Gr and Ga genomes,respectively,were annotated and divided into 18 subfamilies,which showed distinct divergence in gene structure and expression patterns during fiber development.In addition,when the functional parameters were examined,clear divergence was observed within tandem clusters,which suggested that subfunctionalization had occurred among duplicate genes.The expression patterns of homologous gene pairs also changed,suggestive of the diversification of gene function during the evolution of diploid cotton.These findings provide insights into the mechanisms underlying the functional differentiation of duplicated NAC-TFs genes in two diploid cotton species.展开更多
基金This work was supported by a grant from the National Science Foundation （Grant No. ISO-0744170）. No conflict of interest declared.
文摘We report the genome-wide analysis of direct target genes of SND1 and VND7, two Arabidopsis thaliana NAC domain transcription factors that are master regulators of secondary wall biosynthesis in fibers and vessels, respectively. Systematic mapping of the SND1 binding sequence using electrophoretic mobility shift assay and transactivation analysis demonstrated that SND1 together with other secondary wall NACs （SWNs）, including VND6, VND7, NST1, and NST2, bind to an imperfect palindromic 19-bp consensus sequence designated as secondary wall NAC binding element （SNBE）, （T/A）NN（C/T） （TICIG）TNNNNNNNA（AIC）GN（AJCIT） （A/T）, in the promoters of their direct targets. Genome-wide analysis of direct targets of SND1 and VND7 revealed that they directly activate the expression of not only downstream transcription factors, but also a number of non-transcription factor genes involved in secondary wall biosynthesis, cell wall modification, and programmed cell death, the promoters of which all contain multiple SNBE sites. SND1 and VND7 directly regulate the expression of a set of common targets but each of them also preferentially induces a distinct set of direct targets, which is likely attributed to their differential activation strength toward SNBE sites. Complementation study showed that the SWNs were able to rescue the secondary wall defect in the sndl nstl mutant, indicating that they are functionally interchangeable. Together, our results provide important insight into the complex transcriptional program and the evolutionary mechanism underlying secondary wall biosynthesis, cell wall modification, and programmed cell death in secondary wall-containing cell types.
文摘NAC proteins are plant-specific transcription factors and enriched with members involved in plant response to drought stress. In this study, we analyzed the expression profiles of TaNAC69 in bread wheat using Affymetrix Wheat Genome Array datasets and quantitative RT-PCR. TaNAC69 expression was positively associated with wheat responses to both abiotic and biotic stresses and was closely correlated with a number of stress up-regulated genes. The functional analyses of TaNAC69 in transgenic wheat showed that TaNAC69 driven by a barley drought-inducible HvDhn4s promoter led to marked drought-inducible overexpression of TaNAC69 in the leaves and roots of transgenic lines. The HvDhn4s：Ta- NAC69 transgenic lines produced more shoot biomass under combined mild salt stress and water-limitation conditions, had longer root and more root biomass under polyethylene glycol-induced dehydration. Analysis of transgenic lines with constitutive overexpression of TaNAC69 showed the enhanced expression levels of several stress up-regulated genes. DNA-binding assays revealed that TaNAC69 and its rice homolog （ONAC131） were capable of binding to the promoter elements of three rice genes （chitinase, ZlM, and glyoxalase I） and an Arabidopsis glyoxalase I family gene, which are homologs of TaNAC69 up-regulated stress genes. These data suggest that TaNAC69 is involved in regulating stress upregulated genes and wheat adaptation to drought stress.
基金supported by the National Natural Science Foundation of China(31000732)the National High Technology Research and Development Program of China (2013AA210100)
文摘NAC domain proteins are plant-specific transcription factors known to play diverse roles in various plant developmental processes. In the present study, we performed the first comprehensive study of the NAC gene family in Gossypium raimondii Ulbr., incorporating phylogenetic, chromosomal location, gene structure, conserved motif, and expression profiling analyses. We identified 145 NAC transcription factor （NAC-TF） genes that were phylogenetically clustered into 18 distinct subfamilies. Of these, 127 NAC-TF genes were distributed across the 13 chromosomes, 80 （55%） were preferentially retained duplicates located in both duplicated regions and six were located in triplicated chromosomal regions. The majority of NAC-TF genes showed temporal-, spatial-, and tissue-specific expression patterns based on tran- scriptomic and qRT-PCR analyses. However, the expression patterns of several duplicate genes were partially redundant, suggesting the occurrence of sub-functionalization during their evolution. Based on their genomic organization, we concluded that genomic duplications contributed significantly to the expansion of the NAC-TF gene family in G. raimondii. Comprehensive analysis of their expression profiles could provide novel insights into the functional divergence among members of the NAC gene family in G. raimondii.
文摘Neoadjuvant chemotherapy followed by surgery （NCS） has not been fully evaluated clinically. Currently, the main regimen of neoadjuvant chemotherapy （NAC） used in NCS includes cisplatin. The antitumor effects of NAC reduce lymph node metastasis and the tumor diameter in patients prior to surgery, and this can reduce the number of high risk patients who require postoperative radiation therapy. Many randomized controlled trials （RCTs） have examined the long-term prognosis of NCS compared to primary surgery, but the utility of NCS remains uncertain. The advent of concurrent chemoradiotherapy （CCRT） has markedly improved the outcome of radiotherapy （RT）, and CCRT is now used as a standard method in many cases of advanced bulky cervical cancer. NCS gives a better treatment outcome than radiation therapy alone, but it is important to verify that NCS gives a similar or better outcome compared to CCRT.
文摘We report here that ORS1, a previously uncharacterized member of the NAC transcription factor family, controls leaf senescence in Arabidopsis thaliana. Overexpression of ORS1 accelerates senescence in transgenic plants, whereas its inhibition delays it. Genes acting downstream of ORS1 were identified by global expression analysis using transgenic plants producing dexamethasone-inducible ORSl-GR fusion protein. Of the 42 up-regulated genes, 30 （-70%） were pre- viously shown to be up-regulated during age-dependent senescence, We also observed that 32 （-76%） of the ORSl-dependent genes were induced by long-term （4 d）, but not short-term （6 h） salinity stress （150 mM NaCI）. Furthermore, expression of 16 and 24 genes, respectively, was induced after 1 and 5 h of treatment with hydrogen peroxide （H2O2）, a reactive oxygen species known to accumulate during salinity stress. ORS1 itself was found to be rapidly and strongly induced by H2O2 treatment in both leaves and roots. Using in vitro binding site selection, we determined the preferred binding motif of ORS1 and found it to be present in half of the ORSl-dependent genes. ORS1 is a paralog of ORE1/ ANACO92/AtNAC2, a previously reported regulator of leaf senescence. Phylogenetic footprinting revealed evolutionary conservation of the ORS1 and ORE1 promoter sequences in different Brassicaceae species, indicating strong positive selection acting on both genes. We conclude that ORS1, similarly to ORE1, triggers expression of senescence-associated genes through a regulatory network that may involve cross-talk with saltand H2O2-dependent signaling pathways.
基金the National Natural Science Foundation of China(Grant Nos.30730022 and 30870486)the National Basic Research Program(973 Program)(Grant No.2007CB914304)the National Major Projects(grant Nos.2009ZX09311-001 and 2009ZX10004-304).
文摘The importance of NAC(named as NAM,ATAF1,2,and CUC2)proteins in plant development,transcription regulation and regulatory pathways involving proteinprotein interactions has been increasingly recognized.We report here the high resolution crystal structure of SNAC1(stress-responsive NAC)NAC domain at 2.5Å.Although the structure of the SNAC1 NAC domain shares a structural similarity with the reported structure of the ANAC NAC1 domain,some key features,especially relating to two loop regions which potentially take the responsibility for DNA-binding,distinguish the SNAC1 NAC domain from other reported NAC structures.Moreover,the dimerization of the SNAC1 NAC domain is demonstrated by both soluble and crystalline conditions,suggesting this dimeric state should be conserved in this type of NAC family.Additionally,we discuss the possible NAC-DNA binding model according to the structure and reported biological evidences.
基金the National High Technology Research and Development Program of China (2013AA102601)the National Natural Science Foundation of China (31471538)
文摘Determining how function evolves following gene duplication is necessary for understanding gene expansion.Transcription factors(TFs)are a class of proteins that regulate gene expression by binding to specific cis-acting elements in the promoters of target genes,subsequently activating or repressing their transcription.In the present study,we systematically examined the functional diversification of the NAC transcription factor(NAC-TFs)family by analyzing their chromosomal location,structure,phylogeny,and expression pattern in Gossypium raimondii(Gr)and G.arboreum(Ga).The 145 and 141 NAC genes identified in the Gr and Ga genomes,respectively,were annotated and divided into 18 subfamilies,which showed distinct divergence in gene structure and expression patterns during fiber development.In addition,when the functional parameters were examined,clear divergence was observed within tandem clusters,which suggested that subfunctionalization had occurred among duplicate genes.The expression patterns of homologous gene pairs also changed,suggestive of the diversification of gene function during the evolution of diploid cotton.These findings provide insights into the mechanisms underlying the functional differentiation of duplicated NAC-TFs genes in two diploid cotton species.
