In other cases, the 35S promoter may not be active in specific plant tissues thereby rendering it ineffective for directing high levels of spatial transgene expression.
Plasmid pGBKT7 contains an ADH1 promoter which directs high level expression of fusion protein in yeast; it also contains a T7 promoter and a c-Myc epitope tag.
In vitro and in vivo studies have shown that C1 + R1 or P1 can direct high level of expression from promoters containing the C1/R1 or P1 binding sites identified previously in the a1 and c2 gene promoter [ 12, 19- 21].
RNA virus vectors are attractive vaccine delivery agents capable of directing high-level gene expression without integration into host cell DNA.
A rCDV strain also was engineered that contained the luciferase gene inserted between the P and M genes; this virus directed high levels of luciferase expression in infected cells.
Heparanase cDNA cloned in pcDNA3 vector was used to direct high levels of expression in mammalian cells, driven by a strong viral (CMV) promoter.
The GUBQ1 promoter directs high levels of GUS expression in young leaves of both Gladiolus and Arabidopsis.
In other instances, viral-derived promoter sequences are known to direct high levels of gene expression in a wide array of dicot and monocot species.
These enhancer elements could be used to design synthetic promoters that could direct high levels of expression while maintaining cell specificity and responsiveness to Pi- or N-deprivation.
We chose the αMHC promoter because others have demonstrated, using traditional transgenic procedures, that it directs high levels of reporter gene expression specifically in cardiac tissue of early mouse embryos [ 16- 18].
The ability of constitutive promoters to direct high levels of transgene expression can be a limiting factor when temporal and spatial gene expression patterns are required to achieve manipulation of specific plant organs or developmental stages.
