# US 7,410,765 B2 · System for protease mediated protein expression > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,410,765 B2 - Document ID: US7410765B2 - Status: Granted - Kind: B2 - Application number: 11/281,644 - Filed: 2005-11-17 - Published: 2006-05-18 - Granted: 2008-08-12 - Earliest claimed: 2004-11-17 - Assignees: The Regents of the University of California - Inventors: Arnaud Lacoste; Christopher J. Evans - Web page: https://patentgrep.com/patent/US7410765B2 ## CPC - C07K 7/08: having 12 to 20 amino acids (gastrins C07K14/595; somatostatins C07K14/655; melanotropins C07K14/68) - C12N 15/85: for animal cells - C12Q 1/37: involving peptidase or proteinase - C07K 2319/50: containing protease site - G01N 2500/02: Screening involving studying the effect of compounds C on the interaction between interacting molecules A and B (e.g. A = enzyme and B = substrate for A, or A = receptor and B = ligand for the receptor) - C07K: PEPTIDES (peptides in foodstuffs A23; obtaining protein compositions for foodstuffs, working-up proteins for foodstuffs A23J; preparations for medicinal purposes A61K; peptides containing beta-lactam rings C07D; cyclic dipeptides not having in their molecule any other peptide link than those which form their ring, e.g. piperazine-2,5-diones, C07D; ergot alkaloids of the cyclic peptide type C07D519/02; macromolecular compounds having statistically distributed amino acid units in their molecules, i.e. when the preparation does not provide for a specific; but for a random sequence of the amino acid units, homopolyamides and block copolyamides derived from amino acids C08G69/00; macromolecular products derived from proteins C08H1/00; preparation of glue or gelatine C09H; single cell proteins, enzymes C12N; genetic engineering processes for obtaining peptides C12N15/00; compositions for measuring or testing processes involving enzymes C12Q; investigation or analysis of biological material G01N33/00) - C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00) - C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract The present invention provides methods and materials that can be used to detect, examine and exploit protease mediated protein expression. An illustrative embodiment of the invention is a polynucleotide encoding a polypeptide having a plurality of operatively linked elements comprising a polypeptide degradation signal that functions as a proteosome substrate; a polypeptide of interest having an observable activity; and a linker disposed between the polypeptide degradation signal and the polypeptide of interest. The linker comprises a protease recognition motif that is capable of being specifically recognized and cleaved by a protease. The activity of the polypeptide of interest is observed when the motif is specifically recognized and cleaved by the protease; and the activity of the polypeptide of interest is decreased or not observed when the motif is not specifically recognized and cleaved by the protease. ## Claims ### Claim 1 A polynucleotide encoding a protease-regulated polypeptide comprising the following operatively linked elements: (a) a nucleic acid sequence encoding a protein degradation signal; (b) a nucleic acid sequence encoding a polypeptide of interest; and (c) a nucleic acid sequence encoding a linker set forth as SEQ ID NO:1 disposed between (a) and (b), wherein the linker comprises a protease recognition motif that is cleaved by a protease; wherein, in the presence of the protease, cleavage of the linker protects the polypeptide of interest from proteasomal degradation; and, in the absence of the protease, activity of the polypeptide of interest is decreased. ### Claim 2 (depends on 1) A first vector comprising the polynucleotide of claim 1. ### Claim 3 (depends on 2) A cell comprising the first vector of claim 2. ### Claim 4 (depends on 1) The polynucleotide of claim 1, wherein the protein degradation signal is a ubiquitin degradation signal. ### Claim 5 (depends on 1) The polynucleotide of claim 1, wherein the polypeptide of interest is a reporter protein whose expression can be detected. ### Claim 6 (depends on 1) The polynucleotide of claim 1, wherein the polypeptide of interest is a therapeutically active polypeptide. ### Claim 7 (depends on 2) The first vector of claim 2, further comprising a promoter and/or an enhancer that modulates the expression of the protease-regulated polypeptide. ### Claim 8 (depends on 3) The cell of claim 3, wherein the polypeptide of interest is a first reporter protein, and the cell further comprises a second vector that encodes a second reporter protein whose expression is modulated by a tissue specific promoter or a tissue specific enhancer. ### Claim 9 (depends on 1) A kit comprising the polynucleotide of claim 1 and a suitable container.