Abstract: A class of mutant forms of p53 protein, such as His273 and Lys285, which are defective in conversion from the latent to the activated state by casein kinase II, but with the ability to be activated for specific DNA binding by the action of ligands such as monoclonal antibody PAb421 and heat shock protein DnaK. Activation of these mutants, which are found at high levels in certain types of tumour, can potentially lead to selective growth arrest and induction of apoptosis in the tumor cells. p53 can be constitutively activated also by deletion of the C-terminal 30 amino acids. p53 activated in this way, or by ligand binding, can be administered for the purposes of tumour or cell growth suppression.

Abstract: Green fluorescent protein (GFP) is widely used as a reporter in determining gene expression and protein localization. The present invention provides fusion proteins with a half life of ten hours or less. Such proteins may be constructed by fusing C-terminal amino acids of the degradation domain of mouse ornithine decarboxylase (MODC), which contains a PEST sequence, to the C-terminal end of an enhanced variant of GFP (EGFP). Fluorescence intensity of the fusion protein in transfected cells is similar to that of EGFP, but the fusion protein, unlike EGFP, is unstable in the presence of cycloheximide. Specific mutations in the MODC region have resulted in mutants with varying half lives, useful for a variety of purposes.