scholarly journals Ethylene Response of Plum ACC Synthase 1 (ACS1) Promoter is Mediated through the Binding Site of Abscisic Acid Insensitive 5 (ABI5)  

Plants ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 117 ◽  
Author(s):  
Avi Sadka ◽  
Qiaoping Qin ◽  
Jianrong Feng ◽  
Macarena Farcuh ◽  
Lyudmila Shlizerman ◽  
...  

The enzyme 1-amino-cyclopropane-1-carboxylic acid synthase (ACS) participates in the ethylene biosynthesis pathways and it is tightly regulated transcriptionally and post-translationally. Notwithstanding its major role in climacteric fruit ripening, the transcriptional regulation of ACS during ripening is not fully understood. We studied fruit ripening in two Japanese plum cultivars, the climacteric Santa Rosa (SR) and its non-climacteric bud sport mutant, Sweet Miriam (SM). As the two cultivars show considerable difference in ACS expression, they provide a good system for the study of the transcriptional regulation of the gene. To investigate the differential transcriptional regulation of ACS1 genes in the SR and SM, their promoter regions, which showed only minor sequence differences, were isolated and used to identify the binding of transcription factors interacting with specific ACS1 cis-acting elements. Three transcription factors (TFs), abscisic acid-insensitive 5 (ABI5), GLABRA 2 (GL2), and TCP2, showed specific binding to the ACS1 promoter. Synthetic DNA fragments containing multiple cis-acting elements of these TFs fused to β-glucuronidase (GUS), showed the ABI5 binding site mediated ethylene and abscisic acid (ABA) responses of the promoter. While TCP2 and GL2 showed constant and similar expression levels in SM and SR fruit during ripening, ABI5 expression in SM fruits was lower than in SR fruits during advanced fruit ripening states. Overall, the work demonstrates the complex transcriptional regulation of ACS1.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Niels J. Nieuwenhuizen ◽  
Xiuyin Chen ◽  
Mickaël Pellan ◽  
Lei Zhang ◽  
Lindy Guo ◽  
...  

Abstract Background The phytohormone ethylene controls many processes in plant development and acts as a key signaling molecule in response to biotic and abiotic stresses: it is rapidly induced by flooding, wounding, drought, and pathogen attack as well as during abscission and fruit ripening. In kiwifruit (Actinidia spp.), fruit ripening is characterized by two distinct phases: an early phase of system-1 ethylene biosynthesis characterized by absence of autocatalytic ethylene, followed by a late burst of autocatalytic (system-2) ethylene accompanied by aroma production and further ripening. Progress has been made in understanding the transcriptional regulation of kiwifruit fruit ripening but the regulation of system-1 ethylene biosynthesis remains largely unknown. The aim of this work is to better understand the transcriptional regulation of both systems of ethylene biosynthesis in contrasting kiwifruit organs: fruit and leaves. Results A detailed molecular study in kiwifruit (A. chinensis) revealed that ethylene biosynthesis was regulated differently between leaf and fruit after mechanical wounding. In fruit, wound ethylene biosynthesis was accompanied by transcriptional increases in 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS), ACC oxidase (ACO) and members of the NAC class of transcription factors (TFs). However, in kiwifruit leaves, wound-specific transcriptional increases were largely absent, despite a more rapid induction of ethylene production compared to fruit, suggesting that post-transcriptional control mechanisms in kiwifruit leaves are more important. One ACS member, AcACS1, appears to fulfil a dominant double role; controlling both fruit wound (system-1) and autocatalytic ripening (system-2) ethylene biosynthesis. In kiwifruit, transcriptional regulation of both system-1 and -2 ethylene in fruit appears to be controlled by temporal up-regulation of four NAC (NAM, ATAF1/2, CUC2) TFs (AcNAC1–4) that induce AcACS1 expression by directly binding to the AcACS1 promoter as shown using gel-shift (EMSA) and by activation of the AcACS1 promoter in planta as shown by gene activation assays combined with promoter deletion analysis. Conclusions Our results indicate that in kiwifruit the NAC TFs AcNAC2–4 regulate both system-1 and -2 ethylene biosynthesis in fruit during wounding and ripening through control of AcACS1 expression levels but not in leaves where post-transcriptional/translational regulatory mechanisms may prevail.


Microbiology ◽  
2005 ◽  
Vol 151 (1) ◽  
pp. 259-268 ◽  
Author(s):  
Birgit Baumgarth ◽  
Frank Wilco Bartels ◽  
Dario Anselmetti ◽  
Anke Becker ◽  
Robert Ros

The exopolysaccharide galactoglucan promotes the establishment of symbiosis between the nitrogen-fixing Gram-negative soil bacterium Sinorhizobium meliloti 2011 and its host plant alfalfa. The transcriptional regulator ExpG activates expression of galactoglucan biosynthesis genes by direct binding to the expA1, expG/expD1 and expE1 promoter regions. ExpG is a member of the MarR family of regulatory proteins. Analysis of target sequences of an ExpG(His)6 fusion protein in the exp promoter regions resulted in the identification of a binding site composed of a conserved palindromic region and two associated sequence motifs. Association and dissociation kinetics of the specific binding of ExpG(His)6 to this binding site were characterized by standard biochemical methods and by single-molecule spectroscopy based on the atomic force microscope (AFM). Dynamic force spectroscopy indicated a distinct difference in the kinetics between the wild-type binding sequence and two mutated binding sites, leading to a closer understanding of the ExpG–DNA interaction.


1994 ◽  
Vol 14 (11) ◽  
pp. 7517-7526 ◽  
Author(s):  
H S Ip ◽  
D B Wilson ◽  
M Heikinheimo ◽  
Z Tang ◽  
C N Ting ◽  
...  

The unique contractile phenotype of cardiac myocytes is determined by the expression of a set of cardiac muscle-specific genes. By analogy to other mammalian developmental systems, it is likely that the coordinate expression of cardiac genes is controlled by lineage-specific transcription factors that interact with promoter and enhancer elements in the transcriptional regulatory regions of these genes. Although previous reports have identified several cardiac muscle-specific transcriptional elements, relatively little is known about the lineage-specific transcription factors that regulate these elements. In this report, we demonstrate that the slow/cardiac muscle-specific troponin C (cTnC) enhancer contains a specific binding site for the lineage-restricted zinc finger transcription factor GATA-4. This GATA-4-binding site is required for enhancer activity in primary cardiac myocytes. Moreover, the cTnC enhancer can be transactivated by overexpression of GATA-4 in non-cardiac muscle cells such as NIH 3T3 cells. In situ hybridization studies demonstrate that GATA-4 and cTnC have overlapping patterns of expression in the hearts of postimplantation mouse embryos and that GATA-4 gene expression precedes cTnC expression. Indirect immunofluorescence reveals GATA-4 expression in cultured cardiac myocytes from neonatal rats. Taken together, these results are consistent with a model in which GATA-4 functions to direct tissue-specific gene expression during mammalian cardiac development.


2009 ◽  
Vol 191 (14) ◽  
pp. 4513-4521 ◽  
Author(s):  
Victor J. McAlister ◽  
Gail E. Christie

ABSTRACT The Serratia marcescens NucC protein is structurally and functionally homologous to the P2 Ogr family of eubacterial zinc finger transcription factors required for late gene expression in P2- and P4-related bacteriophages. These activators exhibit site-specific binding to a conserved DNA sequence, TGT-N3-R-N4-Y-N3-aCA, that is located upstream of NucC-dependent S. marcescens promoters and the late promoters of P2-related phages. In this report we describe the interactions of NucC with the P2 FETUD late operon promoter P F . NucC is shown to bind P F as a tetramer and to make 12 symmetrical contacts to the DNA phosphodiester backbone. The backbone contacts are centered on the TGT-N3-R-N4-Y-N3-aCA motif. Major groove base contacts can be seen at most positions within the ∼24-bp binding site. Minor groove contacts map to adjacent positions in the downstream half of the binding site, which corresponds to the area in which the DNA also appears to be bent by NucC binding. NucC binding provides a new example of protein-DNA interaction that is strikingly different from the DNA binding demonstrated for eukaryotic zinc-finger transcription factors.


2020 ◽  
Author(s):  
Yinglin Ji ◽  
Yi Qu ◽  
Zhongyu Jiang ◽  
Xin Su ◽  
Pengtao Yue ◽  
...  

ABSTRACTThe plant hormone ethylene is important for the ripening of climacteric fruit, such as pear (Pyrus ussuriensis), and the brassinosteroid (BR) class of phytohormones affects ethylene biosynthesis during ripening, although via an unknown molecular mechanism. Here, we observed that exogenous BR treatment suppressed ethylene production during pear fruit ripening, and that the expression of the transcription factor PuBZR1 was enhanced by epibrassinolide (EBR) treatment during pear fruit ripening. PuBZR1 was shown to interact with PuACO1, which converts 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene, and suppress its activity. We also observed that BR-activated PuBZR1 bound to the promoters of PuACO1 and of PuACS1a, which encodes ACC synthase, and directly suppressed their transcription. Moreover, PuBZR1 suppressed the expression of transcription factor PuERF2 by binding its promoter, and PuERF2 bound to the promoters of PuACO1 and PuACS1a. We concluded that PuBZR1 indirectly suppresses the transcription of PuACO1 and PuACS1a through its regulation of PuERF2. Ethylene production and the expression profiles of the corresponding apple (Malus domestica) homologs showed similar changes following EBR treatment. Together, these results suggest that BR-activated BZR1 suppresses ACO1 activity and the expression of ACO1 and ACS1a, thereby reducing ethylene production during pear and apple fruit ripening. This likely represents a conserved mechanism by which exogenous BR suppresses ethylene biosynthesis during climacteric fruit ripening.One-sentence summaryBR-activated BZR1 suppresses ACO1 activity and expression of ACO1 and ACS1a, which encode two ethylene biosynthesis enzymes, thereby reducing ethylene production during pear and apple fruit ripening.


1994 ◽  
Vol 14 (11) ◽  
pp. 7517-7526
Author(s):  
H S Ip ◽  
D B Wilson ◽  
M Heikinheimo ◽  
Z Tang ◽  
C N Ting ◽  
...  

The unique contractile phenotype of cardiac myocytes is determined by the expression of a set of cardiac muscle-specific genes. By analogy to other mammalian developmental systems, it is likely that the coordinate expression of cardiac genes is controlled by lineage-specific transcription factors that interact with promoter and enhancer elements in the transcriptional regulatory regions of these genes. Although previous reports have identified several cardiac muscle-specific transcriptional elements, relatively little is known about the lineage-specific transcription factors that regulate these elements. In this report, we demonstrate that the slow/cardiac muscle-specific troponin C (cTnC) enhancer contains a specific binding site for the lineage-restricted zinc finger transcription factor GATA-4. This GATA-4-binding site is required for enhancer activity in primary cardiac myocytes. Moreover, the cTnC enhancer can be transactivated by overexpression of GATA-4 in non-cardiac muscle cells such as NIH 3T3 cells. In situ hybridization studies demonstrate that GATA-4 and cTnC have overlapping patterns of expression in the hearts of postimplantation mouse embryos and that GATA-4 gene expression precedes cTnC expression. Indirect immunofluorescence reveals GATA-4 expression in cultured cardiac myocytes from neonatal rats. Taken together, these results are consistent with a model in which GATA-4 functions to direct tissue-specific gene expression during mammalian cardiac development.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yudong Liu ◽  
Yuan Shi ◽  
Deding Su ◽  
Wang Lu ◽  
Zhengguo Li

AbstractGRAS proteins are plant-specific transcription factors that play crucial roles in plant development and stress responses. However, their involvement in the ripening of economically important fruits and their transcriptional regulatory mechanisms remain largely unclear. Here, we demonstrated that SlGRAS4, encoding a transcription factor of the GRAS family, was induced by the tomato ripening process and regulated by ethylene. Overexpression of SlGRAS4 accelerated fruit ripening, increased the total carotenoid content and increased PSY1 expression in SlGRAS4-OE fruit compared to wild-type fruit. The expression levels of key ethylene biosynthesis genes (SlACS2, SlACS4, SlACO1, and SlACO3) and crucial ripening regulators (RIN and NOR) were increased in SlGRAS4-OE fruit. The negative regulator of tomato fruit ripening, SlMADS1, was repressed in OE fruit. Exogenous ethylene and 1-MCP treatment revealed that more endogenous ethylene was derived in SlGRAS4-OE fruit. More obvious phenotypes were observed in OE seedlings after ACC treatment. Yeast one-hybrid and dual-luciferase assays confirmed that SlGRAS4 can directly bind SlACO1 and SlACO3 promoters to activate their transcription, and SlGRAS4 can also directly repress SlMADS1 expression. Our study identified that SlGRAS4 acts as a new regulator of fruit ripening by regulating ethylene biosynthesis genes in a direct manner. This provides new knowledge of GRAS transcription factors involved in regulating fruit ripening.


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