Promoters induced by environmental factors such as water or salt stress, anaerobiosis, temperature, illumination and wounding have potential for use in the development of plants resistant to various stress conditions. These promoters contain regulatory elements that respond to such environmental stimuli.
Temperature-induced promoters include cold- and heat-shock-induced promoters. In many cases, these promoters are able to operate under normal temperature conditions, which vary according to the organism, but when either cold or heat is applied, the promoters maintain activity. In addition, expression can be enhanced by the application of higher or lower temperature as compared to the normal temperature conditions. One of the best studied eukaryotic heat-shock systems is the one found in Drosophila (fruit fly).
In plants, light-regulated promoters are critical in regulating plant growth and development through the modulation of expression of light-responsive genes. Light-responsive elements from genes such as the small subunit of ribulose-1,5-bisphosphate carboxylase-oxygenase (rbcS) gene, the chlorophyl a/b binding protein, and the chalcone synthase have been widely studied. A molecular dissection of their sequences has shown multiple cis-acting elements for light-dependent gene expression. The light-regulated elements in these promoters exhibit some properties of enhancer-like elements. It is unlikely that a single cis element is sufficient to confer light responsiveness to a non-light regulated promoter. In addition, light-regulated gene expression is under the influence of multiple environmental factors.
The patents presented in this section relate to promoters responsive to temperature and light. The promoters are derived from genes from multiple organisms including bacteria and plants. Methods to use promoters responsive to heat, cold, light or darkness in general terms are part of the inventions discussed here. In some cases, such as in patents related to promoters responsive to cold and light stimuli, particular DNA sequences of promoters are claimed.
The selected analyzed patents are categorized as follows: