FAX2 Mediates Fatty Acid Export from Plastids in Developing Arabidopsis Seeds

2019 ◽  
Vol 60 (10) ◽  
pp. 2231-2242 ◽  
Author(s):  
Yinshuai Tian ◽  
Xueyan Lv ◽  
Guilan Xie ◽  
Linghui Wang ◽  
Tingwei Dai ◽  
...  
Keyword(s):  
Target Gene ◽  
Seed Oil ◽  
Mutant Cell ◽  
Lipid Production ◽  
Building Blocks ◽  
Wild Type ◽  
Oil Accumulation ◽  
Oil Synthesis ◽  
Family Protein ◽  
Synthesis Activity

Abstract Vegetable oils are mainly stored in the form of triacylglycerol (TAG) in oilseeds. Fatty acids (FAs), one of the building blocks for TAG assembly, are synthesized in plastids and then exported to the endoplasmic reticulum for storage oil synthesis. A recent study demonstrated that the export of FAs from plastids was mediated by a FAX (FA export) family protein. However, the significance of FAs export from plastid during seed oil accumulation has not been investigated. In this study, we found that FAX2 was highly expressed in developing Arabidopsis seeds and the expression level was consistent with FAs synthesis activity. FAX2 mutant seeds showed an approximately 18% reduction of lipid levels compared with wild-type seeds. By contrast, overexpression of FAX2 enhanced seed lipid accumulation by up to 30%. The FAs export activity of FAX2 was confirmed by yeast mutant cell complementation analysis. Our results showed that FAX2 could interact with other proteins to facilitate FAs transport. Taken together, these results indicate that FAX2-mediated FA export from plastids is important for seed oil accumulation, and that FAX2 can be used as a target gene for increasing lipid production in oilseeds.

Effect of soluble sugar content in silique wall on seed oil accumulation during the seed-filling stage in Brassica napus

2018 ◽  
Vol 69 (12) ◽  
pp. 1251
Author(s):  
Fei Ni ◽  
Jiahuan Liu ◽  
Jing Zhang ◽  
Mohammad Nauman Khan ◽  
Tao Luo ◽  
...  
Keyword(s):  
Seed Yield ◽  
Seed Oil ◽  
Sugar Content ◽  
Soluble Sugar ◽  
C:N Ratio ◽  
Oil Accumulation ◽  
N Application ◽  
Soluble Sugar Content ◽  
Oil Synthesis ◽  
Oil Concentration

Soluble sugar content in silique wall and seeds of rapeseed (Brassica napus L.) has significant effects on seed oil formation and accumulation. We studied the relationship between soluble sugar content in B. napus seeds and silique wall and oil concentration under field conditions in two cropping seasons, and examined changes in soluble sugar content in seeds and silique wall under different nitrogen (N) levels. Two commercialised Chinese rapeseed varieties, HZ9 and HZ62, with high seed yield and different N responses were used. Our results indicated that carbon (C):N ratio and soluble sugar content in silique wall had the greater effect on seed oil concentration. When C:N ratio and soluble sugar content in silique wall were within 5–15% and 10–25%, respectively, plants had relatively well coordinated C and N metabolism, facilitating oil accumulation. During 25–35 days of silique development, when C:N ratio and soluble sugar content in silique wall were within 10–15 and 15–25%, respectively, oil synthesis was fastest; the highest accumulation rate was 3.8% per day. When they were each <5%, seeds tended to mature, and oil synthesis gradually decreased, ceased or degraded. During the early stage of silique development, if C:N ratio and soluble sugar content in silique wall were >15% and 30%, there was no apparent tendency for oil accumulation, probably because of adverse environmental conditions. When N application increased from 0 to 270kg ha–1, final oil concentration in seeds decreased by 0.024%. In summary, C:N ratio and soluble sugar content in silique wall are important in regulating seed oil concentration, whereas excessive N application significantly reduced seed oil concentration. Therefore, appropriate reduction of N application would save resources, provide environment benefits and increase rapeseed oil production with no substantial reduction in seed yield, through coordinated seed yield and oil concentration.

scholarly journals In SilicoIdentification and Comparative Genomics of Candidate Genes Involved in Biosynthesis and Accumulation of Seed Oil in Plants

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Arti Sharma ◽  
Rajinder Singh Chauhan
Keyword(s):  
Fatty Acids ◽  
Comparative Genomics ◽  
Plant Species ◽  
Seed Oil ◽  
Structure And Function ◽  
Oil Bodies ◽  
Oil Accumulation ◽  
Oil Synthesis ◽  
Total Oil ◽  
And Function

Genes involved in fatty acids biosynthesis, modification and oil body formation are expected to be conserved in structure and function in different plant species. However, significant differences in the composition of fatty acids and total oil contents in seeds have been observed in different plant species. Comparative genomics was performed on 261 genes involved in fatty acids biosynthesis, TAG synthesis, and oil bodies formation in Arabidopsis,Brassica rapa, castor bean and soybean.In silicoexpression analysis revealed that stearoyl desaturase, FatB, FAD2, oleosin and DGAT are highly abundant in seeds, thereby considered as ideal candidates for mining of favorable alleles in natural population. Gene structure analysis for major genes, ACCase, FatA, FatB, FAD2, FAD3 and DGAT, which are known to play crucial role in oil synthesis revealed that there are uncommon variations (SNPs and INDELs) which lead to varying content and composition of fatty acids in seed oil. The predicted variations can provide good targets for seed oil QTL identification, understanding the molecular mechanism of seed oil accumulation, and genetic modification to enhance seed oil yield in plants.

scholarly journals The AML-associated K313 mutation enhances C/EBPα activity by leading to C/EBPα overexpression

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ian Edward Gentle ◽  
Isabel Moelter ◽  
Mohamed Tarek Badr ◽  
Konstanze Döhner ◽  
Michael Lübbert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Wild Type ◽  
Elevated Expression ◽  
Factor C ◽  
Acute Myeloid

AbstractMutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

scholarly journals Cellular retinol-binding protein type III is a PPARγ target gene and plays a role in lipid metabolism

2008 ◽  
Vol 295 (6) ◽  
pp. E1358-E1368 ◽  
Author(s):  
Cynthia F. Zizola ◽  
Gary J. Schwartz ◽  
Silke Vogel
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Free Fatty Acid ◽  
Target Gene ◽  
Binding Protein ◽  
Retinol Binding Protein ◽  
Wild Type ◽  
Type Iii ◽  
Cellular Retinol Binding Protein

Cellular retinol-binding protein (CRBP) type III (CRBP-III) belongs to the family of intracellular lipid-binding proteins, which includes the adipocyte-binding protein aP2. In the cytosol, CRBP-III binds retinol, the precursor of retinyl ester and the active metabolite retinoic acid. The goal of the present work is to understand the regulation of CRBP-III expression and its role in lipid metabolism. Using EMSAs, luciferase reporter assays, and chromatin immunoprecipitation assays, we found that CRBP-III is a direct target of peroxisome proliferator-activated receptor-γ (PPARγ). Moreover, CRBP-III expression was induced in adipose tissue of mice after treatment with the PPARγ agonist rosiglitazone. To examine a potential role of CRBP-III in regulating lipid metabolism in vivo, CRBP-III-deficient (C-III-KO) mice were maintained on a high-fat diet (HFD). Hepatic steatosis was decreased in HFD-fed C-III-KO compared with HFD-fed wild-type mice. These differences were partly explained by decreased serum free fatty acid levels and decreased free fatty acid efflux from adipose tissue of C-III-KO mice. In addition, the lack of CRBP-III was associated with reduced food intake, increased respiratory energy ratio, and altered body composition, with decreased adiposity and increased lean body mass. Furthermore, expression of genes involved in mitochondrial fatty acid oxidation in brown adipose tissue was increased in C-III-KO mice, and C-III-KO mice were more cold tolerant than wild-type mice fed an HFD. In summary, we demonstrate that CRBP-III is a PPARγ target gene and plays a role in lipid and whole body energy metabolism.

scholarly journals Functional Promiscuity of Gene Regulation by Serpentine Receptors in Dictyostelium discoideum

1998 ◽  
Vol 18 (10) ◽  
pp. 5744-5749 ◽  
Author(s):  
Irene Verkerke-Van Wijk ◽  
Ji-Yun Kim ◽  
Raymond Brandt ◽  
Peter N. Devreotes ◽  
Pauline Schaap
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Dictyostelium Discoideum ◽  
Developmental Regulation ◽  
Mutant Cell ◽  
Gene Induction ◽  
Specific Gene ◽  
Wild Type ◽  
Animal Development ◽  
Camp Stimulation

ABSTRACT Serpentine receptors such as smoothened and frizzled play important roles in cell fate determination during animal development. InDictyostelium discoideum, four serpentine cyclic AMP (cAMP) receptors (cARs) regulate expression of multiple classes of developmental genes. To understand their function, it is essential to know whether each cAR is coupled to a specific gene regulatory pathway or whether specificity results from the different developmental regulation of individual cARs. To distinguish between these possibilities, we measured gene induction in car1 car3 double mutant cell lines that express equal levels of either cAR1, cAR2, or cAR3 under a constitutive promoter. We found that all cARs efficiently mediate both aggregative gene induction by cAMP pulses and induction of postaggregative and prespore genes by persistent cAMP stimulation. Two exceptions to this functional promiscuity were observed. (i) Only cAR1 can mediate adenosine inhibition of cAMP-induced prespore gene expression, a phenomenon that was found earlier in wild-type cells. cAR1’s mediation of adenosine inhibition suggests that cAR1 normally mediates prespore gene induction. (ii) Only cAR2 allows entry into the prestalk pathway. Prestalk gene expression is induced by differentiation-inducing factor (DIF) but only after cells have been prestimulated with cAMP. We found that DIF-induced prestalk gene expression is 10 times higher in constitutive cAR2 expressors than in constitutive cAR1 or cAR3 expressors (which still have endogenous cAR2), suggesting that cAR2 mediates induction of DIF competence. Since in wild-type slugs cAR2 is expressed only in anterior cells, this could explain the so far puzzling observations that prestalk cells differentiate at the anterior region but that DIF levels are actually higher at the posterior region. After the initial induction of DIF competence, cAMP becomes a repressor of prestalk gene expression. This function can again be mediated by cAR1, cAR2, and cAR3.

scholarly journals MiR-365-3p is Involved in IL17-Mediated Asthma in Mouse Model

2020 ◽  
Author(s):  
Weijia Wang ◽  
Ying Li ◽  
Xiaoyan Qu ◽  
Dong Shang ◽  
Qiaohong Qin ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Target Gene ◽  
Alveolar Epithelial Cells ◽  
Mouse Lung ◽  
Collagen Deposition ◽  
Wild Type ◽  
Sterile Saline ◽  
The Relationship

Abstract BACKGROUND The IL-17 superfamily, which mediates cross-talk between the adaptive and innate immune systems, has been associated with severity of asthma. The role of miRNAs in the disease has been paid much attention. To explore the roles of IL-17 in asthma and the relationship between IL-17 and miRNAs, we used a model of severe asthma driven by chronic respiratory exposure to house dust mite (HDM) exposure in wild type and IL-17KO mice, followed with miRNA profiling assays and analysis.METHODS Male and female C57BL/6 mice (6-8 weeks old) and IL-17KO mice (C57BL/6 background) were exposed to purified HDM extract intranasally for 5 days/week for 5 consecutive weeks. Sterile saline was used as the control. The parameters including airway responsiveness, inflammatory cells in bronchoalveolar lavage fluid (BALF), airway smooth muscle bundle, collagen deposition, and cytokine levels in BALF were examined. The miRNA profile of mouse lung tissue was analyzed by microarray assays. The dysregulation of miRNA related to IL-17 and asthma was validated by qRT-PCR. The in vitro cell culture experiment was performed to confirm the relationship between IL-17 and selected miRNA. The regulation of miRNA on predicted target gene was validated by administration of miRNA mimics. RESULTS The expression of IL-17A significantly increased in wild type (WT) mice with HDM exposure compared to the control mice. IL-17 deficiency did not reduce airway hyper responsiveness (AHR) induced by HDM exposure. In comparison to HDM-exposed WT mice, BALF neutrophils in IL-17KO mice were significantly decreased. In WT mice, HDM exposure led to increased expression of IL-4 and KC, which was significantly decreased in IL-17KO mice. Furthermore, under HDM exposure, significantly less airway smooth muscle mass and collagen deposition was found in IL-17KO mice compared to WT mice. In the dysregulated miRNAs, the decreased expression of miR-365-3p in HDM-exposed WT mice was validated, and its expression recovered in IL-17KO mice. Furthermore, miR-365-3p was decreased in mouse alveolar epithelial cells by IL-17 treatment. The transfection of miR-365-3p mimics decreased the expression of predicted target gene ARRB2.

scholarly journals Biochemical pathways in seed oil synthesis

2013 ◽  
Vol 16 (3) ◽  
pp. 358-364 ◽  
Author(s):  
Philip D Bates ◽  
Sten Stymne ◽  
John Ohlrogge
Keyword(s):  
Seed Oil ◽  
Biochemical Pathways ◽  
Oil Synthesis

Polypeptide synthesis in cell cycle mutants of fission yeast

1981 ◽  
Vol 51 (1) ◽  
pp. 203-217
Author(s):  
D.P. Dickinson
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Fission Yeast ◽  
Gel Electrophoresis ◽  
Mutant Cell ◽  
Wild Type ◽  
Unsuccessful Attempt ◽  
Dependent Sequence ◽  
Polypeptide Synthesis ◽  
Cellular Components

The cell cycle of a growing cel is characterized by 3 main periodic events: DNA synthesis mitosis and cell division. These events generally lie in a dependent sequence, in which one event cannot occur unless preceding events have occurred. The existence of dependent sequences of events raises the possibility that at least some of the gene products involved in the events are synthesized in a dependent sequence parallel to the observable events. To test this hypothesis, the patterns of polypeptide synthesis were investigated in 2 types of cell cycle mutant of the fission yeast Schizosaccharomyces pombe: temperature-sensitive cell cycle (ts cdc) mutants. which become blocked in cell cycle progress at the restrictive temperature; and wee I mutants, which are defective in size control over nuclear division, and which divide at a small size. Cells of mutants and wild-type cells were labelled with [35S[sulphate under conditions designed to maximize any differences between the labelling patterns of wild-type and mutant cell polypeptides. The polypeptides were then separated by O'Farrell 2-dimensional gel electrophoresis, and the patterns compared. Although both types of mutation affect cell cycle control, and cause a considerable alteration in the relative proportions of cellular components, an examination of over 700 polypeptides detected on gels revealed no qualitative differences between wild-type and mutant cell polypeptides. These results suggest that a large majority of the more abundant polypeptides in the growing cell are synthesized independently of cell cycle controls directly related to DNA synthesis and division, and that the synthesis of these polypeptides can occur in the absence of normal progress through the cell cycle. Dependent sequences of gene expression do not appear to make a significant contribution to total polypeptide synthesis during the cell cycle, or to the occurrence of periodic cell cycle events such as mitosis. It is suggested that such cell cycle events may result largely through the reorganization of existing cellular components, rather than by the synthesis of new ones. An unsuccessful attempt was made to detect the wee I gene product on gels by surveying a range of mutants for changes in an individual spot. The limitations of gel electrophoresis for this type of survey, and other cell cycle experiments, are discussed.

Mutants lacking myosin II cannot resist forces generated during multicellular morphogenesis

1995 ◽  
Vol 108 (3) ◽  
pp. 1105-1115 ◽  
Author(s):  
E. Shelden ◽  
D.A. Knecht
Keyword(s):  
Cell Morphology ◽  
Mutant Cell ◽  
Myosin Ii ◽  
Cell Phenotype ◽  
Computer Assisted ◽  
Wild Type ◽  
Isolated Cells ◽  
Multicellular Development ◽  
Periodic Movement ◽  
Mutant Cells

We have used fluorescent labeling, confocal microscopy and computer-assisted motion analysis to observe and quantify individual wild-type and myosin II mutant cell behavior during early multicellular development in Dictyostelium discoideum. When cultured with an excess of unlabeled wild-type cells, labeled control cells are randomly distributed within aggregation streams, while myosin II mutant cells are found primarily at the lateral edges of streams. Wild-type cells move at average rates of 8.5 +/- 4.9 microns/min within aggregation streams and can exhibit regular periodic movement at 3.5 minute intervals; half as long as the 7 minute period reported previously for isolated cells. Myosin II mutants under the same conditions move at 5.0 +/- 4.8 microns/min, twice as fast as reported previously for isolated myosin II mutant cells, and fail to display regular periodic movement. When removed from aggregation streams myosin II mutant cells move at only 2.5 +/- 2.0 microns/min, while wild-type cells under these conditions move at 5.9 +/- 4.5 microns/min. Analysis of cell morphology further reveals that myosin II mutant cells are grossly and dynamically deformed within wild-type aggregation streams but not when removed from streams and examined in isolation. These data reveal that the loss of myosin II has dramatic consequences for cells undergoing multicellular development. The segregation of mutant cells to aggregation stream edges demonstrates that myosin II mutants are unable to penetrate a multicellular mass of wild-type cells, while the observed distortion of myosin II mutant cells suggests that the cortex of such cells is too flacid to resist forces generated during movement. The increased rate of mutant cell movement and distortion of mutant cell morphology seen within wild-type aggregation streams further argues both that movement of wild-type cells within a multicellular mass can generate traction forces on neighboring cells and that mutant cell morphology and behavior can be altered by these forces. In addition, the distortion of myosin II mutant cells within wild-type aggregation streams indicates that myosin is not required for the formation of cell-cell contacts. Finally, the consequences of the loss of myosin II for cells during multicellular development are much more severe than has been previously revealed for isolated cells. The techniques used here to analyze the behavior of individual cells within multicellular aggregates provide a more sensitive assay of mutant cell phenotype than has been previously available and will be generally applicable to the study of motility and cytoskeletal mutants in Dictyostelium.

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