Precise spatiotemporal control of the timing and extent of asymmetric cell divisions(AcDs)is essential for plant development.In the Arabidopsis root,ground tissue maturation involves an additional AcD of the endo-derm...Precise spatiotemporal control of the timing and extent of asymmetric cell divisions(AcDs)is essential for plant development.In the Arabidopsis root,ground tissue maturation involves an additional AcD of the endo-dermis that maintains the inner cell layer as the endodermis and generates the middle cortex to the outside.Through regulation of the cell cycle regulator CYCLIND6;1(CYCD6;1),the transcription factors SCARECROW(SCR)and SHORT-ROOT(SHR)play critical roles in this process.In the present study,we found that loss of function of NAC1,a NAC transcription factor family gene,causes markedly increased periclinal cell divisions in the root endodermis.Importantly,NAC1 directly represses the transcription of CYCD6;1 by recruiting the co-repressor TOPLESS(TPL),creating a fine-tuned mechanism to maintain proper root ground tissue patterning by limiting production of middle cortex cells.Biochemical and genetic analyses further showed that NAC1 physically interacts with SCR and SHR to restrict excessive periclinal cell divisions in the endo-dermis during root middle cortex formation.Although NAC1-TPL is recruited to the CYCD6;1 promoter and represses its transcription in an SCR-dependent manner,NAC1 and SHR antagonize each other to regu-late the expression of CYCD6;1.Collectively,our study provides mechanistic insights into how the NAC1-TPL module integrates with the master transcriptional regulators SCR and SHR to control root ground tissue patterning by fine-tuning spatiotemporal expression of CYCD6;1 in Arabidopsis.展开更多
A 1050 bp up-stream regulatory fragment of the transcription factor gene NAC1 in Arabidopsis thaliana was isolated using polymerase chain reaction(PCR)based techniques.The fragment was used to substitute the 35S promo...A 1050 bp up-stream regulatory fragment of the transcription factor gene NAC1 in Arabidopsis thaliana was isolated using polymerase chain reaction(PCR)based techniques.The fragment was used to substitute the 35S promoter of the pBI121 plasmid to construct a β-glucuronidase gene(GUS)expression system.The construct was introduced into tobacco(Nico- tiana tabaccum)plants by the Agrobacterium-mediated transferring method.GUS expression pattern was studied by using the transgenic lines.The results showed that the GUS driven by the NAC1 up-stream regulatory region was specifically expressed in the root meristem region,basal areas of the lateral root primordium and the lateral roots.The GUS expression was induced by 3-indolebutyric acid (IBA)and gibberellins(GA3 and GA4+7).The results indicated that the up-stream regulatory fragment of NAC1 responded to plant hormones.The fragment might be involved in both auxins and gibberel- lins signaling in promoting the development of lateral roots.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
基金supported by the National Natural Science Foundation of China(32170338 and 32061143005)Innovative Research Groups of Shandong University(2020QNQT014)+3 种基金the Shandong Province Natural Science Foundation of the Major Basic Research Program(2017C03)(to Z.D.)by the National Natural Science Foundation of China(32170311 and 31970192)the Shandong Province Funds for Excellent Young Scholars(ZR2020YQ19)the Program of Shandong University Qilu Young Scholars(to X.K.).
文摘Precise spatiotemporal control of the timing and extent of asymmetric cell divisions(AcDs)is essential for plant development.In the Arabidopsis root,ground tissue maturation involves an additional AcD of the endo-dermis that maintains the inner cell layer as the endodermis and generates the middle cortex to the outside.Through regulation of the cell cycle regulator CYCLIND6;1(CYCD6;1),the transcription factors SCARECROW(SCR)and SHORT-ROOT(SHR)play critical roles in this process.In the present study,we found that loss of function of NAC1,a NAC transcription factor family gene,causes markedly increased periclinal cell divisions in the root endodermis.Importantly,NAC1 directly represses the transcription of CYCD6;1 by recruiting the co-repressor TOPLESS(TPL),creating a fine-tuned mechanism to maintain proper root ground tissue patterning by limiting production of middle cortex cells.Biochemical and genetic analyses further showed that NAC1 physically interacts with SCR and SHR to restrict excessive periclinal cell divisions in the endo-dermis during root middle cortex formation.Although NAC1-TPL is recruited to the CYCD6;1 promoter and represses its transcription in an SCR-dependent manner,NAC1 and SHR antagonize each other to regu-late the expression of CYCD6;1.Collectively,our study provides mechanistic insights into how the NAC1-TPL module integrates with the master transcriptional regulators SCR and SHR to control root ground tissue patterning by fine-tuning spatiotemporal expression of CYCD6;1 in Arabidopsis.
基金supported by the National Natural Science Foundation of China(Grant No.30200169)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20010019008).
文摘A 1050 bp up-stream regulatory fragment of the transcription factor gene NAC1 in Arabidopsis thaliana was isolated using polymerase chain reaction(PCR)based techniques.The fragment was used to substitute the 35S promoter of the pBI121 plasmid to construct a β-glucuronidase gene(GUS)expression system.The construct was introduced into tobacco(Nico- tiana tabaccum)plants by the Agrobacterium-mediated transferring method.GUS expression pattern was studied by using the transgenic lines.The results showed that the GUS driven by the NAC1 up-stream regulatory region was specifically expressed in the root meristem region,basal areas of the lateral root primordium and the lateral roots.The GUS expression was induced by 3-indolebutyric acid (IBA)and gibberellins(GA3 and GA4+7).The results indicated that the up-stream regulatory fragment of NAC1 responded to plant hormones.The fragment might be involved in both auxins and gibberel- lins signaling in promoting the development of lateral roots.
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.
