Gene-Regulated Responses

The capability to monitor gene-regulated responses is essential to identify the various steps that lead from the perception of elicitors to their activation of the oxidative burst machinery for defense induction. Powerful genomic approaches have now become available for the main algal models mentioned in this chapter and have allowed investigators to mine putative defense genes. 

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Gene regulation by tocopherols has mainly been associated with PKC because of its deactivation by a-tocopherol and its contribution in the regulation of a number of transcription factors (NF-kappaB, API). A direct participation of the pregnane X receptor (PXR)/ retinoid X receptor (RXR) has been also shown. The antioxidant-responsive element (ARE) and the TGF-beta-responsive element appear in some cases to be implicated as well. The obser ved immunmodulatory function of a-tocopherol may also be attributed to the fact that the release of the proinflammatory cytokine interlukin-l 3 can be inhibited by a-tocopherol via... 

ERGs and Differential Gene Regulation Signals Pathways Early Gene Response... 

The identification of the few genes regulated by hormones, among the multitude of the genes that are expressed in each cell, is a first-order problem. What makes the identification possible is the existence of some short specific sequences of DNA, situated in the promoter region of each gene, that are recognized by the dimer of the hormone receptor. These sequences are called hormone response elements (HRE) (Seiler-Tuyns et al. 1986 Tzukerman et al. 1994). 

Fig. 1.7. Interaction of receptor with hormone response element. The hormone response elements are located in the promoter region of genes regulated by hormones with nuclear receptors. They are constituted of sequences from 13 to 15 nucleotides. The elements of estrogen response are formed by two semi-elements, which are sequences of 5 nucleotides, and a spacer of 3 unspecific nucleotides (n). The interaction is produced so that the section of the zinc fingers of the receptor lodges in the main furrow of the DNA double helix...

NEFF, M.M., NGUYEN, S.M., MALANCHARUVIL, E.J., FUJIOKA, S., NOGUCHI, T., SETO, H., TSUBUKI, M., HONDA, T TAKATSUTO, S., YOSHIDA, S., CHORY, J., BAS1 A gene regulating brassinosteroid levels and light responsiveness in Arabidopsis, Proc. Natl. Acad. Sci. USA, 1999, 96,15316-15323. 

NEFF, M. M., NGUYEN, M.S., BAS1 A gene regulating brassinosteroid levels and light responsiveness in Arabidopsis, Proc. Natl. Acad. Sci. USA, 1999, 96, 15316-15323. 

At the level of a single cell, bound carriers/receptors are known to trigger both short-term responses, such as the activation of various intracellular enzymes and long-term responses involving gene regulation, including the synthesis of... 

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