Differential expression of the transfected liver-specific alpha 1-inhibitor III gene in normal hepatocytes and hepatoma cells in culture.
Normal and malignant hepatocytes were transfected during log phase culture with a nested series of DNA plasmids containing 5'-flanking regions of the rat liver-specific acute phase plasma proteinase alpha 1-inhibitor III (alpha 1 I3) gene. Under these conditions, luciferase reporter gene expression in primary adult rat and mouse hepatocytes was 10-fold higher than luciferase expression in hepatoma lines (human HepG2 and Hep3B; rat FAZA). Optimal expression in primary rat hepatocytes required regions stretching 2214 bp 5'-upstream of the transcription start site. Shorter 5'-flanking sequences were optimal for expression in hepatoma cells (-1025 and -186 bp for rat and human lines, respectively) and primary mouse hepatocytes (-225 bp). In contrast, regions from -186 to -225 bp drove luciferase expression in primary rat hepatocytes, but only 20-75% of optimal levels. Qualitative differences were unaccounted for by non-equivalent uptake of plasmid DNA, suggesting that tissue specific gene expression is regulated differently in normal and malignant cells, and with apparent species specificity.
Koch
K S
KS
Department of Pharmacology, University of California, San Diego, La Jolla 92093.
Lu
X P
XP
Brenner
D A
DA
Leffert
H L
HL
D000209:Acute-Phase Proteins; D000818:Animals; D001798:Blood Proteins / Q000235:genetics*; D002478:Cells, Cultured; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism; D008297:Male; D011480:Protease Inhibitors / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D014162:Transfection; D016211:Transforming Growth Factor alpha / Q000494:pharmacology
D000209:Acute-Phase Proteins; D001798:Blood Proteins; D011480:Protease Inhibitors; D011993:Recombinant Fusion Proteins; D016211:Transforming Growth Factor alpha; C017894:alpha 1-inhibitor 3