Modulation of the Activity of an Avian Gene Transferred into a Mammalian Cell by Cell Fusion

AUTOR(ES)

Klinger, Harold P.

RESUMO

Mouse A9 cells, deficient in hypoxanthine phosphoribosyltransferase (EC 2.4.2.8), were fused with normal chick erythrocytes and selected in hypoxanthine-aminopterin-thymidine medium for cells with hypoxanthine phosphoribosyltransferase activity. Recovered hybrid cells produced the chick hypoxanthine phosphoribosyltransferase exclusively, as demonstrated by electrophoretic mobility and immunoprecipitation tests, even though no chick chromosomes or chick cell-surface antigens could be identified in the hybrids. Surprisingly, the expression of the chick hypoxanthine phosphoribosyl-transferase activity in the mouse/chick hybrids required the presence of aminopterin in the growth medium; in its absence, enzyme synthesis decreased markedly. Because of the rapid and reversible modulation of hypoxanthine phosphoribosyltransferase activity, the hybrid cells could proliferate equally well in media containing hypoxanthine-aminopterin-thymidine or 8-azaguanine. Cellular selection was definitely ruled out as a possible cause. These results confirm previous reports that specific genetic information can be selectively transferred from one cell to another of a distant species. Furthermore, they demonstrate that an avian gene, whose activity is normally expressed constitutively, can become facultative when integrated into a mammalian cell. This seems to be the first instance where heterologous gene activity has been shown to be reversibly modulated in hybrid cells.

Documentos Relacionados

• Cell-Cell Fusion Induced by the Avian Reovirus Membrane Fusion Protein Is Regulated by Protein Degradation
• Definition of the ovalbumin gene promoter by transfer of an ovalglobin fusion gene into cultured cells.
• Mammalian cell transformation by a murine retrovirus vector containing the avian erythroblastosis virus erbB gene.
• Gene expression and cell fusion analyzed by lacZ complementation in mammalian cells.
• Photoregulation of a phytochrome gene promoter from oat transferred into rice by particle bombardment.