Expression of alpha-fetoprotein and albumin genes in a rat hepatoma cell line SY/1/80: Evidence for the need of species specific serum factors

Abstract

The expression of alpha-fetoprotein and albumin genes has been studied in a rat hepatoma cell line (SY/1/80) developed from a liver cell tumor induced with di-ethylnitrosamine. This original tumor produces both proteins. However, in in vitro propagated hepatoma cells, after passages in growth medium containing new born calf serum, the mRNAs of both proteins were undetectable. Supplementation with rat serum, but not serum from calf, horse or human, in growth medium for this cell line led to resynthesis of albumin and AFPmRNAs. These findings suggest that species specific serum factor(s) play an important role in the regulation of gene expression. Although the nature of the factor(s) and of the mechanism of action remains to be elucidated, this phenomenon may explain the general feature of diminshing abilities of cells to produce specific proteins in continuous subculture using standard calf serum.