Cell Growth & Differentiation, Vol 9, Issue 10 857-867, Copyright © 1998 by American Association of Cancer Research

ARTICLES

Transient accumulation of retinoblastoma/E2F-1 protein complexes correlates with the onset of neuronal differentiation in the developing quail neural retina

A Kastner, X Espanel and G Brun
Laboratoire de Biologie Moleculaire et Cellulaire, UMR49 CNRS, Ecole Normale Superieure de Lyon, France.

Retinoblastoma (Rb) protein has been implicated in the control of cell proliferation and malignant transformation in different cell types. To analyze its role as a promoter of cell growth arrest during development, we have studied the temporal pattern of Rb expression and its association with E2F-1 during embryogenesis of the quail neuroretina. During development of this neural organ, most cells stop dividing and begin to differentiate at embryonic days E6 and E7, as indicated by the decline of cyclin-dependent kinase cdk2 and by an increased level of cdk5. At this stage, we observed a shift of hyperphosphorylated Rb protein to its hypophosphorylated form as well as a decrease of the total level of Rb. The Rb-related protein, p107, is also progressively down-regulated from the E7 stage onwards. P130 levels, on the other hand, actually increase. Moreover, cell cycle exit at E6-E7 is characterized by a sudden and transient rise of the E2F-1/RB complex followed by the appearance of the E2F-4/p130 complex starting at E8. Conversely, expression of adenovirus E1A protein in E6 neuroretina cells leads to a dissociation of E2F-1/Rb complex and suppression of cell growth arrest and differentiation. This suggests that cell cycle exit and re-entry may depend on Rb/E2F-1 interaction. Although the rate of Rb synthesis declines in postmitotic cells, as suggested by in vivo metabolic labeling of the Rb protein, the level of the Rb transcript remains

This article has been cited by other articles:

				R. Parakati and J. X. DiMario Dynamic Transcriptional Regulatory Complexes, Including E2F4, p107, p130, and Sp1, Control Fibroblast Growth Factor Receptor 1 Gene Expression during Myogenesis J. Biol. Chem., June 3, 2005; 280(22): 21284 - 21294. [Abstract] [Full Text] [PDF]

				A. E. Loercher, E. M.H. Tank, R. B. Delston, and J. W. Harbour MITF links differentiation with cell cycle arrest in melanocytes by transcriptional activation of INK4A J. Cell Biol., January 3, 2005; 168(1): 35 - 40. [Abstract] [Full Text] [PDF]

				M.-E. Legrier, A. Ducray, A. Propper, M. Chao, and A. Kastner Cell Cycle Regulation during Mouse Olfactory Neurogenesis Cell Growth Differ., December 1, 2001; 12(12): 591 - 601. [Abstract] [Full Text] [PDF]