Precise identification of gene products in hearts after in vivo gene transfection, using sendai virus-coated proteoliposomes

Both efficient gene transfer and the exact identification of gene product a re required for gene therapy. Gene transfection of green fluorescence prote in (GFP) might be useful for the reporter. After in vivo cotransfection of GFP and beta-galactosidase (beta-Gal) genes in Sendai virus-coated proteoli posomes to rat hearts, we compared the sensitivity and specificity of three methods: GFP detection, histochemical staining (HC) of beta-Gal activity, and immunostaining (LS) of the beta-Gal protein. Fluorescence microscopy an d double staining of HC and IS revealed that both GFP and IS were equally s ensitive and fourfold superior to HC at the peak of gene expression. Howeve r, different from skeletal muscle, the GFP of transfected cardiomyocytes sh owed two demerits: the fluorescence quenching due to the intense staining o f beta-Gal activity, and nonspecific autofluorescence from myocardium. Thus , specific IS would be so far the most reliable to identify the gene produc t in heart. (C) 1999 Academic Press.