# US 11,077,215 B2 · Co-expression of magnetotactic bacterial genes and genes encoding iron handling proteins in cells > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,077,215 B2 - Document ID: US11077215B2 - Status: Granted - Kind: B2 - Application number: 15/121,653 - Filed: 2014-07-08 - Published: 2016-12-22 - Granted: 2021-08-03 - Earliest claimed: 2014-02-25 - Assignees: Multi-Magnetics Incorporated - Applicants: Multi-Magnetics Incorporated - Inventors: Donna E. Goldhawk; D. James Koropatnick; Rene Figueredo; Frank S. Prato; R. Terry Thompson; Neil Gelman - Web page: https://patentgrep.com/patent/US11077215B2 ## CPC - A61K 49/1896: {not provided for elsewhere, e.g. cells, viruses, ghosts, red blood cells, virus capsides} - C07K 14/195: from bacteria - C12N 15/85: for animal cells - C12Q 1/6883: for diseases caused by alterations of genetic material - C12Q 1/689: for bacteria - C12N 2510/00: Genetically modified cells - A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D) - 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 ## Abstract The invention provides an improved modified magnetosome that contains more iron therein with the combination of the expressed genes. This is achieved by co-expression of (a) one or more bacterial magnetotactic genes to amplify iron uptake, compartmentalization and biomineralization in cells, with (b) one or more mammalian iron handling proteins that together augment(s) and/or regulate the cells iron pool. As a result, mammalian cells or bacterial cells that are transfected or transformed, respectively, can be more effectively tracked using various imaging technologies. ## Claims ### Claim 1 An expression system for augmenting and/or regulating iron levels in cells, said expression system comprising (a) a complete or partial bacterial MamAB operon comprising magnetotactic genes to amplify iron uptake, compartmentalization and biomineralization in cells, and (b) one or more genes each encoding one or more eukaryotic ferritin subunits, the one or more genes lacking an iron responsive element (IRE), wherein (a) and (b) are under control of one or more promoters and, optionally, one or more selection markers. ### Claim 2 (depends on 1) The expression system of claim 1 wherein said one or more eukaryotic ferritin subunits are mammalian. ### Claim 3 (depends on 1) The expression system of claim 1, wherein the one or more eukaryotic ferritin subunits comprise both a ferritin heavy subunit and a ferritin light subunit. ### Claim 4 (depends on 1) The expression system of claim 1, wherein said cells are eukaryotic. ### Claim 5 (depends on 1) A cell transformed with the expression system of claim 1. ### Claim 6 (depends on 5) The cell of claim 5, wherein said cell is detected using an imaging system selected from the group consisting of positron emission tomography (PET), magnetic resonance imaging (MRI), gamma-ray imaging camera (GREI-II), computed tomography (CT), Single photon emission computed tomography (SPECT), bioluminescence tomography (BLT), magnetic particle imaging (MPI) and combinations thereof. ### Claim 7 (depends on 1) A method of augmenting and/or regulating iron levels in cells and subsequent detection of the cells, the method comprising utilizing the expression system of claim 1 to co-express said magnetotactic bacterial genes from said MamAB operon and said one or more eukaryotic ferritin subunits to form a magnetosome-like structure containing augmented amounts of iron therein; and detecting the cells using an imaging system selected from the group consisting of positron emission tomography (PET), magnetic resonance imaging (MRI), gamma-ray imaging camera (GREI-II), computed tomography (CT), Single photon emission computed tomography (SPECT), bioluminescence tomography (BLT), magnetic particle imaging (MPI) and combinations thereof. ### Claim 8 (depends on 7) The method of claim 7 for use in one or more of the following: detecting changes in cellular iron; tracking cancer growth and metastasis; image, quantify and/or monitor progression of transplanted stem cells; tracking neurodegenerative disorders; and cell tracking in vivo.