REGULATION OF CELL-GROWTH AND ALTERATION OF GENE-EXPRESSION IN HUMAN HEPATOMA-CELLS BY A CARP MATERNAL GENE

Regulation of cell growth and alteration of gene expression in human hepatoma cells by a carp maternal gene. Bull. Inst. Zool., Academia Sinica 32(3): 204-213. A carp maternal cDNA library was used to transfect tumor-like tilapia ovary cells in culture, and a plasmid was subsequently rescued from a single cell clone. Transfection of the rescued plasmid into human hepatoma cells caused them to lose their tumorous characteristics; they were unable to pile up and failed to grow in soft agar. Moreover, we found that a co-culture of transformed and parental cells, both tilapia ovary and human hepatoma cells, could effectively suppress the tumorous phenotypes of the parental cells. The screening of several cellular proteins by western blot immunostaining showed that ce-fetoprotein and oncogenic proteins, ras, and abl were reduced in transformed cells; in addition, phosphorylated proteins with molecular weights corresponding to pp60src and EGF receptor were decreased. However, the tumor suppressor gene p53 product and a matrix protein collagen type IV were enhanced. Our results suggest that this maternal gene may be directly involved in cell growth and differentiation control.