Constitutive promoters, transgene

Plant phytoene synthase (Psy) has been used in a variety of transgenics. As noted above, P yl over-expression under a strong constitutive promoter caused a decrease in carotenoid accumulation, probably due to transcription silencing. Similarly, over-expression of the gene sequence backward (antisense) also silenced activity. In another approach to over-expression of tomato 1 in fruits, a synthetic alternative in which the third position of each codon was changed in order to avoid transcriptional silencing was successful in conditioning an increase in carotenoid accumulation. 

The phenotypic effects observed under the constitutive expression of GES may also be avoided by the use of inducible promoters. Transgenic Arabidopsis expressing GES controlled by the alcohol-inducible Ale A promoter did not show the lesion phenotype observed under constitutive expression of GES [58]. Recent experiments with wound- and insect-inducible promoters such as that of the potato proteinase inhibitor 11 have been reported [78]. The use of strong inducible promoters that respond to herbivore-feeding may not only minimize toxic effects or costs associated with the constitutive formation of a volatile compound but can also provide the advantage that parasitoids associate volatiles only with the presence of feeding damage by the respective host. 

Transgene with constitutive promoter pm Tissue-specific overexpression, dependent on regulatory sequence of transgene (Section 3.1.1)... 

Gene delivery constitutes an interesting approach to treat diseased striated muscles. Administration of pDNA coding for the dystrophin protein has been extensively studied in animal models of Duchenne or Becker muscular dystrophy and even evaluated in Phase 1 clinical trials. Although most of the cationic vehicles appeared to be relatively inefficient in promoting transgenic expression in the muscle tissue, D-SPM polycations were reported to show a transient increase in reporter gene expression after direct intramuscular injection in skeletal muscles with maximum efficiency. 

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