Antisense Expression and Overexpression of Biotin Carboxylase in Tobacco Leaves

Shintani, David K.; Roesler, Keith R.; Shorrosh, Basil S.; Savage, Linda; Ohlrogge, John B.

doi:10.1104/pp.114.3.881

Cited by 36 publications

(25 citation statements)

References 25 publications

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“…This is not the case, however. Neither the antisense nor the sense expression of the BC or BCCP isoform 2 by nuclear transformation changed in the accumulation of other ACCase subunits, 58,59) indicating that a closely coordinated expression of nuclear-encoded ACCase subunits does not occur, and thus providing support for our proposal.…”

Section: Post-transcriptional Regulationsupporting

confidence: 62%

“…To elevate this ACCase, a few possible methods were examined for BC, BCCP, and -CT. Tobacco BC cDNA was expressed in the sense and antisense orientations using a constitutive promoter in transgenic tobacco plants. 58) In the transformants, the altered BC levels did not affect the expression of the BCCP subunit of ACCase. Arabidopsis BCCP2 cDNA was expressed in the sense and antisense orientations.…”

Section: Manipulation Of the Heteromeric Form Of Accasementioning

confidence: 92%

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Plant Acetyl-CoA Carboxylase: Structure, Biosynthesis, Regulation, and Gene Manipulation for Plant Breeding

Sasaki

Nagano

2004

Bioscience, Biotechnology, and Biochemistry

363

285

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Section: Post-transcriptional Regulationsupporting

confidence: 62%

Section: Manipulation Of the Heteromeric Form Of Accasementioning

confidence: 92%

Plant Acetyl-CoA Carboxylase: Structure, Biosynthesis, Regulation, and Gene Manipulation for Plant Breeding

Sasaki

Nagano

2004

Bioscience, Biotechnology, and Biochemistry

363

285

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“…In support of this, analysis of tobacco (Nicotiana tabacum) plants engineered to constitutively express an antisense transcript of the tobacco biotin carboxylase showed reductions of leaf fatty acid content together with a stunted phenotype (Shintani et al, 1997). Growth phenotypes together with reduction in leaf lipids were also obtained with antisense constructs directed against stearoyl-ACP desaturase and ACP4 and with induced mutations in the fab2 and enoyl-ACP reductase genes (Lightner et al, 1994;Mou et al, 2000;Branen et al, 2003).…”

mentioning

confidence: 85%

Metabolic Responses to the Reduction in Palmitate Caused by Disruption of the FATB Gene in Arabidopsis

et al. 2004

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Disruption of the FATB gene in Arabidopsis results in a two-thirds reduction in saturated fatty acids, largely palmitate, in the leaf extra-plastidic phospholipids and a reduction in the growth rate of the mutant compared to wild type (Bonaventure G, Salas JJ, Pollard MR, Ohlrogge JB [2003] Plant Cell 15: 1020-1033. In this study, we report that although fatb-ko seedlings grow more slowly than wild type, the rate of fatty acid synthesis in leaves of the mutant increases by 40%. This results in approximately the same amount of palmitate exported from the plastid as in wild type but an increase in oleate export of about 55%. To maintain constant amounts of fatty acids in leaves, thereby counterbalancing their higher rate of production, the mutant also increases its rate of fatty acid degradation. Although fatb-ko leaves have higher rates of fatty acid synthesis and turnover, the relative proportions of membrane lipids are similar to wild type. Thus, homeostatic mechanisms to preserve membrane compositions compensate for substantial changes in rates of fatty acid and glycerolipid metabolism in the mutant. Pulse-chase labeling studies show that in fatb-ko leaves there is a net increase in the synthesis of both prokaryotic and eukaryotic lipids and consequently of their turnover. The net loss of palmitate from phosphatidylcholine plus phosphatidylethanolamine is similar for wild type and mutant, suggesting that mechanisms are not present that can preferentially preserve the saturated fatty acids. In summary, the leaf cell responds to the loss of saturated fatty acid production in the fatb-ko mutant by increasing both fatty acid synthesis and degradation, but in doing so the mechanisms for increased fatty acid turnover contribute to the lowering of the percentage of saturated fatty acids found in eukaryotic lipids.In plants, the major site for de novo fatty acid synthesis (FAS) occurs in the plastid (Ohlrogge et al., 1979). Fatty acids are either utilized in this organelle or exported to supply diverse cytoplasmic biosynthetic pathways and cellular processes. Production of fatty acids for export depends on the activity of acyl-ACP thioesterases (FATs) that hydrolyze acyl-acyl carrier protein (acyl-ACP) to release free fatty acids and ACP (for review, see Voelker et al., 1997). After export, the free fatty acids are re-esterified to CoA to form the cytosolic acyl-CoA pool (Pollard and Ohlrogge, 1999). In mesophyll cells, acyl-CoAs are primarily used for the biosynthesis of membrane glycerolipids in the endoplasmic reticulum (Browse and Somerville, 1991). However, in other cell types exported fatty acids have different fates. For example, in embryo cells of oilseeds, the major fraction is incorporated into triacylglycerols, while in epidermal cells a large fraction is utilized for the synthesis of waxes and cutin (Post-Beittenmiller, 1996;Kolattukudy, 2003). Furthermore, all cells synthesize sphingolipids (Lynch, 1993), and we recently estimated that as much as 30% to 40% of exported palmitate is needed for sphingoid ba...

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“…The fractional nature of this ACCase mutant and its seed specificity are two beneficial characteristics of this mutant. Complete or nearly complete loss-of-function mutations for de novo fatty acid synthetic enzymes (or proteins involved in their regulation) produce lethal or retarded growth phenotypes (Shintani et al, 1997;Mou et al, 2000;Bonaventure et al, 2003;Millar et al, 2003). The lethality of knockout mutants for this pathway is likely due to the requirement of acyl chains for membrane lipid production (Thelen and Ohlrogge, 2002b).…”

mentioning

confidence: 99%

System Analysis of an Arabidopsis Mutant Altered in de Novo Fatty Acid Synthesis Reveals Diverse Changes in Seed Composition and Metabolism

et al. 2009

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Embryo-specific overexpression of biotin carboxyl carrier protein 2 (BCCP2) inhibited plastid acetyl-coenzyme A carboxylase (ACCase), resulting in altered oil, protein, and carbohydrate composition in mature Arabidopsis (Arabidopsis thaliana) seed. To characterize gene and protein regulatory consequences of this mutation, global microarray, two-dimensional difference gel electrophoresis, iTRAQ, and quantitative immunoblotting were performed in parallel. These analyses revealed that (1) transgenic overexpression of BCCP2 did not affect the expression of three other ACCase subunits; (2) four subunits to plastid pyruvate dehydrogenase complex were 25% to 70% down-regulated at protein but not transcript levels; (3) key glycolysis and de novo fatty acid/lipid synthesis enzymes were induced; (4) multiple storage proteins, but not cognate transcripts, were upregulated; and (5) the biotin synthesis pathway was up-regulated at both transcript and protein levels. Biotin production appears closely matched to endogenous BCCP levels, since overexpression of BCCP2 produced mostly apo-BCCP2 and the resulting ACCase-compromised, low-oil phenotype. Differential expression of glycolysis, plastid pyruvate dehydrogenase complex, fatty acid, and lipid synthesis activities indicate multiple, complex regulatory responses including feedback as well as futile "feed-forward" elicitation in the case of fatty acid and lipid biosynthetic enzymes. Induction of storage proteins reveals that oil and protein synthesis share carbon intermediate(s) and that reducing malonyl-coenzyme A flow into fatty acids diverts carbon into amino acid and protein synthesis.

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Antisense Expression and Overexpression of Biotin Carboxylase in Tobacco Leaves

Cited by 36 publications

References 25 publications

Plant Acetyl-CoA Carboxylase: Structure, Biosynthesis, Regulation, and Gene Manipulation for Plant Breeding

Plant Acetyl-CoA Carboxylase: Structure, Biosynthesis, Regulation, and Gene Manipulation for Plant Breeding

Metabolic Responses to the Reduction in Palmitate Caused by Disruption of the FATB Gene in Arabidopsis

System Analysis of an Arabidopsis Mutant Altered in de Novo Fatty Acid Synthesis Reveals Diverse Changes in Seed Composition and Metabolism

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