Since transgene silencing was found in transgenic plants,many scholars have studied it extensively and considered that it has three functional mechanisms:post dependent gene silencing,transcriptional gene silencing,p...Since transgene silencing was found in transgenic plants,many scholars have studied it extensively and considered that it has three functional mechanisms:post dependent gene silencing,transcriptional gene silencing,post transcriptional gene silencing.At the moment,people have mainly focused on the study of post transcriptional gene silencing and found its features:extensivity,conduction and peculiarity,also put forward some hypothesis for its mechanisms,for example,RNA threshold model,aberrant RNA model,inter or intra molecular base pairing model and so on.Furthermore,post transcriptional gene silencing is being applied in gene engineering of plants.Recently the people have found that post transcriptional gene silencing has bearing on capacity plants resisting virus.Many researchers have studied post transcriptional gene silencing,but there are some questions which need be solved in the future.This article summarizes progresses in features,mechanisms,applies of post transcriptional gene silencing about transgenic plants.展开更多
While human immunodeficiency virus 1(HIV-1) infectionis controlled through continuous, life-long use of a combination of drugs targeting different steps of the virus cycle, HIV-1 is never completely eradicated from th...While human immunodeficiency virus 1(HIV-1) infectionis controlled through continuous, life-long use of a combination of drugs targeting different steps of the virus cycle, HIV-1 is never completely eradicated from the body. Despite decades of research there is still no effective vaccine to prevent HIV-1 infection. Therefore, the possibility of an RNA interference(RNAi)-based cure has become an increasingly explored approach. Endogenous gene expression is controlled at both, transcriptional and post-transcriptional levels by noncoding RNAs, which act through diverse molecular mechanisms including RNAi. RNAi has the potential to control the turning on/off of specific genes through transcriptional gene silencing(TGS), as well as finetuning their expression through post-transcriptional gene silencing(PTGS). In this review we will describe in detail the canonical RNAi pathways for PTGS and TGS, the relationship of TGS with other silencing mechanisms and will discuss a variety of approaches developed to suppress HIV-1 via manipulation of RNAi. We will briefly compare RNAi strategies against other approaches developed to target the virus, highlighting their potential to overcome the major obstacle to finding a cure, which is the specific targeting of the HIV-1 reservoir within latently infected cells.展开更多
Developing transgenics that express high levels of Cry1Ac protein, and at the same time, are phenotypically normal, has not been an easy task to achieve. It has been routinely observed that most of the transgenic plan...Developing transgenics that express high levels of Cry1Ac protein, and at the same time, are phenotypically normal, has not been an easy task to achieve. It has been routinely observed that most of the transgenic plants that survive, show no or extremely low levels of Cry1Ac protein. However, all of these plants do express the selectable marker, nptII gene. In the present study, we record an interesting observation of how one of the genes (cry1Ac) on a single T-DNA fragment is selectively silenced, keeping the expression of the other gene (nptII) intact. Further, this silenced state is inherited.展开更多
The NAC(NAM,ATAF,and CUC)family is considered one of the largest families of plant transcription factor,and its members are involved in fruit ripening.Abscisic acid(ABA)has been demonstrated to modulate the fruit ripe...The NAC(NAM,ATAF,and CUC)family is considered one of the largest families of plant transcription factor,and its members are involved in fruit ripening.Abscisic acid(ABA)has been demonstrated to modulate the fruit ripening process.By applying the virus-induced gene silencing method and next-generation sequencing technology,we conducted a compara-tive analysis of the eff ects of SNAC4(SlNAC48,accession number:NM 001279348.2)and SNAC9(SlNAC19,accession number:XM 004236996.2)on tomato fruit ripening.The results of high-throughput sequencing identified 1262 significant(p<0.05)diff erentially expressed genes(DEGs)in SNAC4-silenced fruit compared to control fruit,while 655 DEGs were identified in SNAC9-silenced fruit.In addition,we selected 26 and 30 significant DEGs(p<0.05 and log 2-fold change>1.0)related to ABA in SNAC4-silenced and SNAC9-silenced tomatoes,respectively,for further analysis.The XET gene and two other genes(E8 and EXP1)were significantly down and upregulated in SNAC4-silenced tomatoes,respectively.However,the PYL9 gene and four other genes(PP2C,CYP707A2,EXPA6,and ACS6)were significantly down and upregulated in SNAC9-silenced tomatoes,respectively.In addition,ten DEGs were selected for use in tests to confirm the accuracy of the transcriptomic results by quantitative real-time polymerase chain reaction(qRT-PCR).Our results highlight the relationship between SNAC4/9 and ABA in the regulation of tomato ripening,which may help provide a theoretical basis for further research on the mechanisms of tomato fruit ripening and senescence.展开更多
Although DNA methylation is known to play an important role in the silencing of transposable elements （TEs） and introduced transgenes, the mechanisms that generate DNA methylation-independent transcrip- tional silen...Although DNA methylation is known to play an important role in the silencing of transposable elements （TEs） and introduced transgenes, the mechanisms that generate DNA methylation-independent transcrip- tional silencing are poorly understood. Previous studies suggest that RNA-directed DNA methylation （RdDM） is required for the silencing of the RD29A-LUC transgene in the Arabidopsis rosl mutant back- ground with defective DNA demethylase. Loss of function of ARGONAUTE 4 （AGO4） gene, which encodes a core RdDM component, partially released the silencing of RD29A-LUC in the rosl/ago4 double mutant plants. A forward genetic screen was performed to identify the mutants with elevated RD29A-LUC trans- gene expression in the rosl/ago4 mutant background. We identified a mutation in the homologous gene of PRP31, which encodes a conserved pre-mRNA splicing factor that regulates the formation of the U4/ U6.U5 snRNP complex in fungi and animals. We previously demonstrated that the splicing factors ZOP1 and STA1 contribute to transcriptional gene silencing. Here, we reveal that Arabidopsis PRP31 associates with ZOP1, STA1, and several other splicing-related proteins, suggesting that these splicing factors are both physically and functionally connected. We show that Arabidopsis PRP31 participates in transcrip- tional gene silencing. Moreover, we report that PRP31, STA1, and ZOP1 are required for development and stress response. Under cold stress, PRP31 is not only necessary for pre-mRNA splicing but also for regulation of cold-responsive gene expression. Our results suggest that the splicing machinery has multiple functions including pre-mRNA splicing, gene regulation, transcriptional gene silencing, and stress response.展开更多
The SU(VAR)-3-9-related protein family member SUVR2 has been previously identified to be involved in transcriptional gene silencing both in RNA-dependent and-independent pathways. It interacts with the chromatin-remod...The SU(VAR)-3-9-related protein family member SUVR2 has been previously identified to be involved in transcriptional gene silencing both in RNA-dependent and-independent pathways. It interacts with the chromatin-remodeling proteins CHR19,CHR27, and CHR28(CHR19/27/28), which are also involved in transcriptional gene silencing. Here our study demonstrated that SUVR2 is almost fully mono-sumoylated in vivo. We successfully identified the exact SUVR2 sumoylation site by combining in vitro mass spectrometric analysis and in vivo immunoblotting confirmation. The luminescence imaging assay and quantitative RT-PCR results demonstrated that SUVR2 sumoylation is involved in transcriptional gene silencing. Furthermore, we found that SUVR2 sumoylation is required for the interaction of SUVR2 with CHR19/27/28, which is consistent with the fact that SUMO proteins are necessary for transcriptional gene silencing. These results suggest that SUVR2 sumoylation contributes to transcriptional gene silencing by facilitating the interaction of SUVR2 with the chromatin-remodeling proteins CHR19/27/28.展开更多
Transcription factors(TFs)orchestrate the regulation of cellular gene expression and thereby determine cell functionality.In this study,we analyzed the distribution of TFs containing domains,which named as ZnFTFs,both...Transcription factors(TFs)orchestrate the regulation of cellular gene expression and thereby determine cell functionality.In this study,we analyzed the distribution of TFs containing domains,which named as ZnFTFs,both in ascomycete and basidiomycete fungi.We found that ZnFTFs were widely distributed in these fungal species,but there was more expansion of the ZnFTF class in Ascomycota than Basidiomycota.We identified 40 ZnFTFs in Ustilaginoidea virens,and demonstrated the involvement of UvZnFTF1 in vegetative growth,conidiation,pigment biosynthesis and pathogenicity.RNA-Seq analysis suggested that UvZnFTF1 may regulate different nutrient metabolism pathways,the production of secondary metabolites,and the expression of pathogen-host interaction genes and secreted protein-encodi ng genes.Analysis of the distributi on of differe nt fungal TFs in U.virens further dem on strated that UvZnFTFs make up a large TF family and may play essential biological roles in U.virens.展开更多
Nuclear envelope proteins have important roles in chromatin organization and signal-dependent transcriptional regulation. A previous study reported that the inner nuclear membrane protein, Otefin （Ote）, was essentia...Nuclear envelope proteins have important roles in chromatin organization and signal-dependent transcriptional regulation. A previous study reported that the inner nuclear membrane protein, Otefin （Ote）, was essential for germline stem cell （GSC） maintenance via interaction with Smad complex. The interaction of Ore with the Smad complex recruits the barn locus to the nuclear periphery and subsequently results in bam transcriptional silencing, revealing that nuclear peripheral localization is essential for barn gene regulation. However, it remains unknown whether the nuclear peripheral localization is sufficient for barn silencing. To address this issue, we have established a tethering system, in which the Gal4 DNA binding domain （DBD） of the Flag：Gal4 DBD：Ote△LEM fusion protein physically interacts with the Gal4 binding sites upstream of bamP-gfp to artificially recruit the reporter gene gfp to the nuclear membrane. Our data demonstrated that the nuclear peripheral localization seemed to affect the expression of the target naked gene in S2 ceils. By contrast, in Drosophila germ cells, the nuclear membrane localization was not sufficient for gene silencing.展开更多
Tomato yellow leaf curl virus(TYLCV)is known to encode 6 canonical viral proteins.Our recent study revealed that TYLCV also encodes some additional small proteins with potential virulence functions.The fifth ORF of TY...Tomato yellow leaf curl virus(TYLCV)is known to encode 6 canonical viral proteins.Our recent study revealed that TYLCV also encodes some additional small proteins with potential virulence functions.The fifth ORF of TYLCV in the complementary sense,which we name C5,is evolutionarily conserved,but little is known about its expression and function during viral infection.Here,we confirmed the expression of the TYLCV C5 by analyzing the promoter activity of its upstream sequences and by detecting the C5 protein in infected cells by using a specific custom-made antibody.Ectopic expression of C5 using a potato virus X(PVX)vector resulted in severe mosaic symptoms and higher virus accumulation levels followed by a burst of reactive oxygen species(ROS)in Nicotiana benthamiana plants.C5 was able to effectively suppress local and systemic post-transcriptional gene silencing(PTGS)induced by single-stranded GFP but not double-stranded GFP,and reversed the transcriptional gene silencing(TGS)of GFP.Furthermore,the mutation of C5 in TYLCV inhibited viral replication and the development of disease symptoms in infected plants.Transgenic overexpression of C5 could complement the virulence of a TYLCV infectious clone encoding a dysfunctional C5.Collectively,this study reveals that TYLCV C5 is a pathogenicity determinant and RNA silencing suppressor,hence expanding our knowledge of the functional repertoire of the TYLCV proteome.展开更多
文摘Since transgene silencing was found in transgenic plants,many scholars have studied it extensively and considered that it has three functional mechanisms:post dependent gene silencing,transcriptional gene silencing,post transcriptional gene silencing.At the moment,people have mainly focused on the study of post transcriptional gene silencing and found its features:extensivity,conduction and peculiarity,also put forward some hypothesis for its mechanisms,for example,RNA threshold model,aberrant RNA model,inter or intra molecular base pairing model and so on.Furthermore,post transcriptional gene silencing is being applied in gene engineering of plants.Recently the people have found that post transcriptional gene silencing has bearing on capacity plants resisting virus.Many researchers have studied post transcriptional gene silencing,but there are some questions which need be solved in the future.This article summarizes progresses in features,mechanisms,applies of post transcriptional gene silencing about transgenic plants.
文摘While human immunodeficiency virus 1(HIV-1) infectionis controlled through continuous, life-long use of a combination of drugs targeting different steps of the virus cycle, HIV-1 is never completely eradicated from the body. Despite decades of research there is still no effective vaccine to prevent HIV-1 infection. Therefore, the possibility of an RNA interference(RNAi)-based cure has become an increasingly explored approach. Endogenous gene expression is controlled at both, transcriptional and post-transcriptional levels by noncoding RNAs, which act through diverse molecular mechanisms including RNAi. RNAi has the potential to control the turning on/off of specific genes through transcriptional gene silencing(TGS), as well as finetuning their expression through post-transcriptional gene silencing(PTGS). In this review we will describe in detail the canonical RNAi pathways for PTGS and TGS, the relationship of TGS with other silencing mechanisms and will discuss a variety of approaches developed to suppress HIV-1 via manipulation of RNAi. We will briefly compare RNAi strategies against other approaches developed to target the virus, highlighting their potential to overcome the major obstacle to finding a cure, which is the specific targeting of the HIV-1 reservoir within latently infected cells.
文摘Developing transgenics that express high levels of Cry1Ac protein, and at the same time, are phenotypically normal, has not been an easy task to achieve. It has been routinely observed that most of the transgenic plants that survive, show no or extremely low levels of Cry1Ac protein. However, all of these plants do express the selectable marker, nptII gene. In the present study, we record an interesting observation of how one of the genes (cry1Ac) on a single T-DNA fragment is selectively silenced, keeping the expression of the other gene (nptII) intact. Further, this silenced state is inherited.
基金supported by the National Natural Science Foundation of China(Nos.31671899 and 31871848)。
文摘The NAC(NAM,ATAF,and CUC)family is considered one of the largest families of plant transcription factor,and its members are involved in fruit ripening.Abscisic acid(ABA)has been demonstrated to modulate the fruit ripening process.By applying the virus-induced gene silencing method and next-generation sequencing technology,we conducted a compara-tive analysis of the eff ects of SNAC4(SlNAC48,accession number:NM 001279348.2)and SNAC9(SlNAC19,accession number:XM 004236996.2)on tomato fruit ripening.The results of high-throughput sequencing identified 1262 significant(p<0.05)diff erentially expressed genes(DEGs)in SNAC4-silenced fruit compared to control fruit,while 655 DEGs were identified in SNAC9-silenced fruit.In addition,we selected 26 and 30 significant DEGs(p<0.05 and log 2-fold change>1.0)related to ABA in SNAC4-silenced and SNAC9-silenced tomatoes,respectively,for further analysis.The XET gene and two other genes(E8 and EXP1)were significantly down and upregulated in SNAC4-silenced tomatoes,respectively.However,the PYL9 gene and four other genes(PP2C,CYP707A2,EXPA6,and ACS6)were significantly down and upregulated in SNAC9-silenced tomatoes,respectively.In addition,ten DEGs were selected for use in tests to confirm the accuracy of the transcriptomic results by quantitative real-time polymerase chain reaction(qRT-PCR).Our results highlight the relationship between SNAC4/9 and ABA in the regulation of tomato ripening,which may help provide a theoretical basis for further research on the mechanisms of tomato fruit ripening and senescence.
文摘Although DNA methylation is known to play an important role in the silencing of transposable elements （TEs） and introduced transgenes, the mechanisms that generate DNA methylation-independent transcrip- tional silencing are poorly understood. Previous studies suggest that RNA-directed DNA methylation （RdDM） is required for the silencing of the RD29A-LUC transgene in the Arabidopsis rosl mutant back- ground with defective DNA demethylase. Loss of function of ARGONAUTE 4 （AGO4） gene, which encodes a core RdDM component, partially released the silencing of RD29A-LUC in the rosl/ago4 double mutant plants. A forward genetic screen was performed to identify the mutants with elevated RD29A-LUC trans- gene expression in the rosl/ago4 mutant background. We identified a mutation in the homologous gene of PRP31, which encodes a conserved pre-mRNA splicing factor that regulates the formation of the U4/ U6.U5 snRNP complex in fungi and animals. We previously demonstrated that the splicing factors ZOP1 and STA1 contribute to transcriptional gene silencing. Here, we reveal that Arabidopsis PRP31 associates with ZOP1, STA1, and several other splicing-related proteins, suggesting that these splicing factors are both physically and functionally connected. We show that Arabidopsis PRP31 participates in transcrip- tional gene silencing. Moreover, we report that PRP31, STA1, and ZOP1 are required for development and stress response. Under cold stress, PRP31 is not only necessary for pre-mRNA splicing but also for regulation of cold-responsive gene expression. Our results suggest that the splicing machinery has multiple functions including pre-mRNA splicing, gene regulation, transcriptional gene silencing, and stress response.
基金supported by the National Key Research and Development Program of China (2016YFA0500801 to Xinjian He)
文摘The SU(VAR)-3-9-related protein family member SUVR2 has been previously identified to be involved in transcriptional gene silencing both in RNA-dependent and-independent pathways. It interacts with the chromatin-remodeling proteins CHR19,CHR27, and CHR28(CHR19/27/28), which are also involved in transcriptional gene silencing. Here our study demonstrated that SUVR2 is almost fully mono-sumoylated in vivo. We successfully identified the exact SUVR2 sumoylation site by combining in vitro mass spectrometric analysis and in vivo immunoblotting confirmation. The luminescence imaging assay and quantitative RT-PCR results demonstrated that SUVR2 sumoylation is involved in transcriptional gene silencing. Furthermore, we found that SUVR2 sumoylation is required for the interaction of SUVR2 with CHR19/27/28, which is consistent with the fact that SUMO proteins are necessary for transcriptional gene silencing. These results suggest that SUVR2 sumoylation contributes to transcriptional gene silencing by facilitating the interaction of SUVR2 with the chromatin-remodeling proteins CHR19/27/28.
基金supported by the National Natural Science Foundation of China(Grant No.31601593)the Young Elite Scientist Sponsorship of China Association for Science and Technology(Grant No.YESS20170108)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20160588).
文摘Transcription factors(TFs)orchestrate the regulation of cellular gene expression and thereby determine cell functionality.In this study,we analyzed the distribution of TFs containing domains,which named as ZnFTFs,both in ascomycete and basidiomycete fungi.We found that ZnFTFs were widely distributed in these fungal species,but there was more expansion of the ZnFTF class in Ascomycota than Basidiomycota.We identified 40 ZnFTFs in Ustilaginoidea virens,and demonstrated the involvement of UvZnFTF1 in vegetative growth,conidiation,pigment biosynthesis and pathogenicity.RNA-Seq analysis suggested that UvZnFTF1 may regulate different nutrient metabolism pathways,the production of secondary metabolites,and the expression of pathogen-host interaction genes and secreted protein-encodi ng genes.Analysis of the distributi on of differe nt fungal TFs in U.virens further dem on strated that UvZnFTFs make up a large TF family and may play essential biological roles in U.virens.
基金supported by the Postdoctoral Science Foundation of China(No.20090460517)
文摘Nuclear envelope proteins have important roles in chromatin organization and signal-dependent transcriptional regulation. A previous study reported that the inner nuclear membrane protein, Otefin （Ote）, was essential for germline stem cell （GSC） maintenance via interaction with Smad complex. The interaction of Ore with the Smad complex recruits the barn locus to the nuclear periphery and subsequently results in bam transcriptional silencing, revealing that nuclear peripheral localization is essential for barn gene regulation. However, it remains unknown whether the nuclear peripheral localization is sufficient for barn silencing. To address this issue, we have established a tethering system, in which the Gal4 DNA binding domain （DBD） of the Flag：Gal4 DBD：Ote△LEM fusion protein physically interacts with the Gal4 binding sites upstream of bamP-gfp to artificially recruit the reporter gene gfp to the nuclear membrane. Our data demonstrated that the nuclear peripheral localization seemed to affect the expression of the target naked gene in S2 ceils. By contrast, in Drosophila germ cells, the nuclear membrane localization was not sufficient for gene silencing.
基金funded by the National Key Research and Development Program of China(2021YFD1400400)the National Natural Science Foundation of China(32172385 and 3193089).
文摘Tomato yellow leaf curl virus(TYLCV)is known to encode 6 canonical viral proteins.Our recent study revealed that TYLCV also encodes some additional small proteins with potential virulence functions.The fifth ORF of TYLCV in the complementary sense,which we name C5,is evolutionarily conserved,but little is known about its expression and function during viral infection.Here,we confirmed the expression of the TYLCV C5 by analyzing the promoter activity of its upstream sequences and by detecting the C5 protein in infected cells by using a specific custom-made antibody.Ectopic expression of C5 using a potato virus X(PVX)vector resulted in severe mosaic symptoms and higher virus accumulation levels followed by a burst of reactive oxygen species(ROS)in Nicotiana benthamiana plants.C5 was able to effectively suppress local and systemic post-transcriptional gene silencing(PTGS)induced by single-stranded GFP but not double-stranded GFP,and reversed the transcriptional gene silencing(TGS)of GFP.Furthermore,the mutation of C5 in TYLCV inhibited viral replication and the development of disease symptoms in infected plants.Transgenic overexpression of C5 could complement the virulence of a TYLCV infectious clone encoding a dysfunctional C5.Collectively,this study reveals that TYLCV C5 is a pathogenicity determinant and RNA silencing suppressor,hence expanding our knowledge of the functional repertoire of the TYLCV proteome.
