Cell division is required for expression of v-myc transforming properties in chicken embryonic neuroretina cells.
We previously reported that avian retroviruses carrying the v-myc oncogene alone fail to induce sustained proliferation and transformation of non-dividing chicken neuroretina (CNR) cells from 7-day-old embryos. However, v-myc is capable of transforming CNR cells which have been induced to multiply by the v-mil oncogene. These results suggest that entry into the cell cycle is required for the transformation of CNR cells by v-myc. To further assess the role of cell division, we investigated the transforming properties of v-myc in CNR cells conditionally induced to divide by the v-src gene or by modified culture conditions. We show that v-myc transforms CNR cells infected with Rous sarcoma virus mutants which induce cell proliferation in the absence of transformation. Expression of these transforming properties in CNR cells infected with temperature-sensitive v-src mutants depends on the continuous mitogenic activity of p60v-src. We also report that v-myc is able to transform CNR cells and to increase their growth potential under culture conditions which allow transient multiplication of uninfected cells. However, these v-myc-transformed cells rapidly cease to divide when returned to culture conditions that restrict the growth of normal cells. Taken together, these results indicate that transformation of CNR cells by the v-myc oncogene continuously depends on their ability to enter the cell cycle.
Bechade
C
C
Institut Curie-Biologie, Centre Universitaire, Orsay, France.
Calothy
G
G
D000818:Animals; D001358:Avian Sarcoma Viruses / Q000235:genetics; D002448:Cell Adhesion; D002455:Cell Division; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D002642:Chick Embryo; D016259:Genes, myc; D007700:Kinetics; D015688:Oncogene Protein pp60(v-src) / Q000235:genetics; D027384:Oncogene Proteins v-raf; D009857:Oncogenes; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D012165:Retinal Ganglion Cells / Q000166:cytology*; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics
D015682:Retroviridae Proteins, Oncogenic; D011505:Protein-Tyrosine Kinases; D015688:Oncogene Protein pp60(v-src); D027384:Oncogene Proteins v-raf