title: [Magnetic resonance imaging (MRI) in evaluation of tyrosinase gene expression in HepG2 cell].
abstract: OBJECTIVE
  Gene therapy is the frontier of life science. There is no perfect method to evaluate gene expression without invasion at present. Medical imaging connecting with molecular biology might be helpful; however, the technology is just on the horizon. The authors conducted this study in vitro by transferring reporter tyrosinase gene into HepG2 cell to apply magnetic resonance imaging (MR) for evaluating gene expression.
  
  
  METHODS
  The plasmid of pcDNA3tyr carried the full-length cDNA of tyrosinase gene was transfected into HepG2 cell by lipofectin, its property of synthesizing melanin was used to produce high signal in T1WI MR image and then to evaluate gene expression. Further identification were performed with searching melanin granules by Fontana staining and searching cDNA of tyrosinase gene using reverse transcription-polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  (1)The melanin granules were found in HepG2 cell using Fontana staining. (2)The cDNA fragment of tyrosinase gene was detectable in transferred HepG2 cell by RT-PCR. (3)Plasmid of pcDNA3tyr was transfected into HepG2 cell and synthesized a large amount of melanin in HepG2 cell; the synthetic melanin appeared high signal in T1WI MR imaging as same as natural melanin and was enough to be detected by MR. And further, the signal intensity was positively related to the amount of transferred plasmid.
  
  
  CONCLUSIONS
  The fact that synthetic melanin of HepG2 cell can be detected by MR demonstrates that medical imaging connecting with molecular biology can be used to evaluate the result of gene expression in vitro.
authors.affiliation: Department of Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510120, PR China. yjpgz@163.net
authors.forename: Jian-Peng
authors.initials: JP
authors.lastname: Yuan
authors.forename: Bi-Ling
authors.initials: BL
authors.lastname: Liang
authors.forename: Bang-Kun
authors.initials: BK
authors.lastname: Xie
authors.forename: Jing-Lian
authors.initials: JL
authors.lastname: Zhong
mesh_terms: D053938:DNA Fragmentation; D015870:Gene Expression; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008543:Melanins / Q000032:analysis*; D014442:Monophenol Monooxygenase / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014407:Tumor Cells, Cultured
chemical_list: D008543:Melanins; D014442:Monophenol Monooxygenase