Transcriptional regulation synthases

Clearly, the control of gene expression at the transcriptional level is a key regulatory mechanism controlling carotenogenesis in vivo. However, post-transcriptional regulation of carotenoid biosynthesis enzymes has been found in chromoplasts of the daffodil. The enzymes phytoene synthase (PSY) and phytoene desaturase (PDS) are inactive in the soluble fraction of the plastid, but are active when membrane-bound (Al-Babili et al, 1996 Schledz et al, 1996). The presence of inactive proteins indicates that a post-translational regulation mechanism is present and is linked to the redox state of the membrane-bound electron acceptors. In addition, substrate specificity of the P- and e-lycopene cyclases may control the proportions of the p, P and P, e carotenoids in plants (Cunningham et al, 1996). 

FEINBAUM, R.L., AUSUBEL, F.M., Transcriptional regulation of the Arabidopsis thaliana chalcone synthase gene, Mol. Cell. Biol., 1988, 8, 1985-1992. 

In addition we have shown that IL-1 also induces the expression of c-jun in both islets and RINm5F cells, and have obtained preliminary evidence for nuclear factor RB (NF-kB) activation (J. A. Corbett and M. L. McDaniel, unpublished observation). TTiese three transcriptional regulators alone or in combination are believed to participate in IL-1-induced expression of nitric oxide synthase by the islet j8 cell. Importantly, Nathan and co-workers have shown the presence of NF-kB response elements upstream of the mouse macrophage iNOS gene (Xie et cd., 1993). 

Siow RC, Li FY, Rowlands DJ, de Winter P, Mann GE. 2007. Cardiovascular targets for estrogens and phytoestrogens Transcriptional regulation of nitric oxide synthase and antioxidant defense genes. Free Radio Biol Med 42 909-925. 

Figure 7.7 The relative location of c/s-elements and putative transcriptional regulators on the tryptophan decarboxylase (TDC), strictosidine synthase (STR), and cytochrome P450 reductase (CPR) gene promotors from Catharanthus roseus. The black box represents elements responsive to elicitor, jasmonate, or UV light. The white box represents a G-box motif, whereas the striped box represents a GCC-box element.

For the aromatic pathway (Figure 30.20), the critical control points are the condensation of phosphoenolpyruvate and erythrose-4-phosphate to 3-deoxy-D-arabinoheptulosonate 7-phosphate, DAHP, by DAHP synthase. For tryptophan, the formation of anthranilic acid from chorismic acid by anthranilate synthase is the second critical control point. The transcriptional regulation was overcome through the use of alternative promoters and allosteric regulation was circumvented by the classical technique of selection for feedback-resistant mutants using toxic analogues of the repressing compounds. 

Transcriptional regulation of ACC synthase Posttranslational regulation of ACC synthase Perception and Signaling Ethylene receptors RTE1/GR CTR1 EIN2 EIN3... 

Fatty acid synthase is transcriptionally regulated by upstream stimulatory factor and sterol regulatory element binding protein Ic (SREBP-lc), in response to feeding/insulin. 

K. Cieslik, C.-M. Lee, J. Tang, K.K. Wu, Transcriptional regulation of endothelial nitric-oxide synthase by an interaction between casein kinase 2 and protein phosphatase 2A, J Biol Chem 274, 34669-34675 (1999). 

In the cytosol, three molecules of acetyl-CoA are condensed to HMG-CoA through successive action of thio-lase and HMG-CoA synthase, respectively (Figure 19-9). HMG-CoA synthase is under transcriptional regulation by the sterol end products. 

Following the discovery of the role of calcineurin in transcription regulation in T-lymphocytes, a large number of calcineurin substrates other than NF-AT have been discovered. These include NO synthase, ion channels, and adenylyl cylase among many others (review Rusnack and Mertz, 2000). 

A Class-IV PHA synthase has been detected in Bacillus megaterium. PhaC and PhaR (the transcriptional regulator of phasin expression), the latter exhibiting only little sequence homology to PhaE but being essential for enzyme activity, constitute this PhaC. Rehm [19] concluded that PhaR, eventually like PhaE, may functionally replace the N-terminus of class-I PhaCs. 

Fukuda, FI., Iritani, N., Sugimoto, T. and Ikeda, H., Transcriptional regulation of fatty acid synthase gene by insuhn/glucose, polyunsaturated fatty acid and leptin in hepatocytes and adipocytes in normal and genetically obese rats, Eur J Biochem 260 (1999) 505-511. 

Rangan, V. S., Oskouian, B. and Smith, S., Identification of an inverted CCAAT box motif in the fatty-acid synthase gene as an essential element for modification of transcriptional regulation by cAMP, J Biol Chem 271 (1996) 2307-2312. 

The glutamine synthase regulatory system has another important function. Protein Pll stimulates the dephosphorylation of the enhancer-binding transcriptional regulator NRI-P (NtrC-P). This slows transcription of the glutamine S5mthase gene (see Fig. 

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