Abstract: Disclosed are isolated DNA constructs including (a) a first DNA sequence including either an inducible promoter sequence responsive to the presence or absence of an exogenous inducer or a developmental gene promoter capable of initiating gene expression in a selected tissue or at a selected stage of development of an organism; (b) a second DNA sequence including a DNA sequence coding for a protease enzyme operably linked and under the control of the promoter sequence specified at (a); whereby the presence or absence of the exogenous inducer or the activation of the developmental gene promoter specified at (a) results in expression of the protease enzyme. These constructs are preferably rendered reversible by the presence of further elements. These constructs can be used in plant or mammalian cells for disruption of cell function, controlling senescence and modifying the metabolism of stored proteins.

Abstract: A promoter comprising the DNA sequence of an oil seed rape cysteine protease gene promoter of class 1, 2 or 6 is described. The promoter may be used in an expression system for at least the tissue or tissues of a germinating seedling or developing grain or plant (e.g. in the root, cotyledons, leaves and stem). In a preferred embodiment, the expression system comprises a disrupter gene fused to a promoter according to the present invention.