Proliferation of chicken neuroretina cells induced by v-src, in vitro, depends on activation of the E2F transcription factor.
Quiescent chicken or quail retina neuroblasts (NR) can be induced to proliferate actively, in culture, by the v-src oncoprotein. The chE2F-1 transcription factor, a physiological partner of the retinoblastoma gene product, is highly expressed in vivo, in dividing chicken neuroretina cells (CNR). It is sharply down-regulated as cells enter the post-mitotic differentiation stage, thus suggesting that E2F activity is a prerequisite for NR cell proliferation. In the present paper, transient expression assays of different forms of chE2F-1 were used to investigate the function of E2F for switching CNR cells from a quiescent to a proliferative state in vitro. Attempts to substitute the effects of v-src by an ectopic expression of E2F-1 were unsuccessful. However, in the same conditions, E2F-1 supports full growth of CEF in serum-depleted medium. Deletion mutants of E2F-1, with potential dominant-negative properties, were transfected in RSV infected CNR cells. One of these truncated mutants induces a G1 phase block in RSV-transformed CNR cells indicating that, although E2F-1 overexpression cannot overcome the cell proliferation block of post-mitotic CNR cells E2F-1, activity is an important component of the growth signal pathway delivered by v-src in these nervous cells.
Pasteau
S
S
Laboratoire de Biologie Moléculaire et Cellulaire de l'Ecole Normale Supérieure de Lyon, UMR49 CNRS/ENS, France.
Loiseau
L
L
Brun
G
G
D000818:Animals; D001358:Avian Sarcoma Viruses / Q000235:genetics; D002352:Carrier Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002454:Cell Differentiation; D002455:Cell Division; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D002645:Chickens; D016895:Culture Media, Serum-Free; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D009154:Mutation; D015688:Oncogene Protein pp60(v-src) / Q000494:pharmacology*; D012160:Retina / Q000166:cytology*; D056465:Retinoblastoma-Binding Protein 1; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D016895:Culture Media, Serum-Free; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D056465:Retinoblastoma-Binding Protein 1; D014157:Transcription Factors; D015688:Oncogene Protein pp60(v-src)