title: MR imaging and scintigraphy of gene expression through melanin induction.
abstract: OBJECTIVE
  To determine whether an expression vector that encodes for human tyrosinase, the key enzyme in the melanin production pathway, can be used to image gene expression with magnetic resonance (MR) imaging and scintigraphy.
  
  
  METHODS
  Mouse fibroblasts and human embryonal kidney cells were transfected with an expression vector that contained a complete complementary DNA sequence that encodes the human tyrosinase gene (pcDNA3tyr). Transfected cells were assayed for messenger RNA presence, melanin staining, and indium-111 binding; scintigraphy and MR imaging were performed.
  
  
  RESULTS
  Transfected cells contained tyrosinase messenger RNA and stained positively for melanin. Transfected cells had a higher In-111 binding capacity than nontransfected cells, a difference readily detectable with scintigraphy. MR imaging showed transfected cells to have markedly higher signal intensity after gene transfer than nontransfected cells.
  
  
  CONCLUSIONS
  Gene transfer and expression in cell culture can be detected with MR imaging and scintigraphy. The proposed strategy of using an imaging marker gene may have a substantial effect on the noninvasive imaging of gene therapy.
authors.affiliation: Department of Radiology, Center for Molecular Imaging Research, Massachusetts General Hospital, Charlestown 02129, USA.
authors.forename: R
authors.initials: R
authors.lastname: Weissleder
authors.forename: M
authors.initials: M
authors.lastname: Simonova
authors.forename: A
authors.initials: A
authors.lastname: Bogdanova
authors.forename: S
authors.initials: S
authors.lastname: Bredow
authors.forename: W S
authors.initials: WS
authors.lastname: Enochs
authors.forename: A
authors.initials: A
authors.lastname: Bogdanov
mesh_terms: D000818:Animals; D015972:Gene Expression Regulation, Neoplastic; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D006801:Humans; D007205:Indium Radioisotopes; D008279:Magnetic Resonance Imaging; D008543:Melanins / Q000096:biosynthesis*; D008545:Melanoma / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism / Q000628:therapy; D051379:Mice; D014442:Monophenol Monooxygenase / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism / Q000628:therapy; D014162:Transfection
chemical_list: D007205:Indium Radioisotopes; D008543:Melanins; D014442:Monophenol Monooxygenase