Methods for magnetic resonance imaging

Abstract

In certain aspects the present invention provides methods and compositions related to contrast agents for magnetic resonance imaging. In certain variations, contrast agents provided herein are generated in situ via genetic instructions and become potent upon sequestering available metal atoms. Exemplary contrast agents include metal-binding proteins.

1 - 20 . (canceled) 
     
     
         21 . A fusion protein comprising a ferritin heavy chain subunit and a ferritin light chain subunit, wherein the ferritin heavy chain subunit is positioned C-terminal to the light chain subunit. 
     
     
         22 . The fusion protein of  claim 21 , wherein a linker connects the ferritin heavy chain subunit to the ferritin light chain subunit. 
     
     
         23 . A nucleic acid encoding the fusion protein of  claim 21 . 
     
     
         24 . A vector for transfection of a multicellular organism comprising a recombinant nucleic acid encoding a fusion protein of  claim 21 , wherein the vector is a viral vector. 
     
     
         25 . The vector of  claim 24 , wherein the viral vector is derived from one or more of the viruses selected from the group consisting of: an adenovirus, an adenovirus-associated virus, a herpes simplex virus, a retrovirus, an alphavirus, a poxvirus, an arena virus, a vaccinia virus, an influenza virus and a polio virus. 
     
     
         26 . A method of generating an image of a subject material comprising providing a subject material comprising a plurality of cells wherein a subset of the cells comprise a MRI-detectable amount of contrast fusion protein; and imaging the cells by magnetic resonance imaging, wherein the contrast fusion protein comprises a ferritin heavy chain subunit and a ferritin light chain subunit. 
     
     
         27 . A superparamagnetic complex comprising the fusion protein of  claim 21 . 
     
     
         28 . The fusion protein of  claim 21 , wherein the ferritin heavy chain subunit and ferritin light chain subunit are 90% identical to the amino acid sequences of SEQ ID NO: 2 and SEQ ID NO: 4, respectively.