Second, the mNUS promoter was applied for generating a tissue-specific system for stable gene delivery.
Here, we depict two tissue-specific systems, which show differential effects during heat stress.
The abstraction involves a pair of tissue specific dynamical system models of the same biological process, both manipulated synchronously through a set of common input functions.
This established tissue specific RNAi system takes advantage of an RNAi insensitive strain lacking RDE-1, in which tissue-specific re-expression of RDE-1 reactivates RNAi sensitivity in the targeted tissue (Qadota et al., 2007).
In combination with appropriate delivery systems, the tissue specific pEPito vector system will allow higher tissue-specificity with less undesired side effects and is suitable for long term transgene expression in vivo within gene therapeutical approaches.
Many types of adult tissues, especially for high turnover tissues such as the blood and intestinal system, stand on a hierarchical tissue-specific stem cell system.
For example, the tissue specific spots A (nervous system tissues), B (muscle tissues) and F (immune system tissues) contain about 30% - 40% genes which are not assigned to any of the gene sets tested and about 50% genes which are members of gene sets not listed at the top of the list (details are given in Additional file 1).
However, unlike in other tissues, a tissue specific inducible Cre recombinase system that allows temporal and spatial deletion of a target DNA fragment is still not available for in vivo functional gene annotation in hepatocytes.
Differences in default gene-expression profile requirements between tissues, and subsequently variable susceptibility for loss or gain of different chromosome areas could account for the tissue specific pathology in multi-system diseases in general and in mosaic states as well.
Combining the properties of an episomally replicating, non-integrating vector system with tissue specific promoters should in principle give a high level of biosafety when compared for example to integrating viral vector systems.
The human AFP-promoter in combination with the hCMV enhancer element was demonstrated to be a valuable tissue-specific promoter for targeting hepatocellular carcinomas with non-viral gene delivery system, and tissue specific replication could be shown in vitro with the muscle specific SM22 promoter.
