Abstract
E2F is a complex family of transcription factors which appears to regulate the transcription of genes required for the S phase of the mammalian cell cycle. In the present work, we have examined the mechanisms regulating E2F-3 accumulation in mouse fibroblasts. We have determined that E2F-3 DNA binding activity is restricted to the G1/S transition and S phase in both normal BALB/c-3T3 fibroblasts and in an SV40 virus-transformed BALB/c-3T3 derivative. Immunoblot analysis indicates that G0 and G1 cells have little or no E2F-3 polypeptide and that the increase in the DNA binding activity of E2F-3 at the G1/S boundary is reflected by an increase in total E2F-3 protein. In contrast to the E2F-3 polypeptide, RNAse protection assays demonstrate that the E2F-3 mRNA is clearly present in G0 and G1 cells. Finally, pulse/chase experiments indicate that the half-life of E2F-3 is approximately 40-fold greater in cells blocked in S phase relative to asynchronously growing cells. Together, these results indicate that the accumulation E2F-3 at S phase may be regulated, at least in part, at the level of protein stability.
Citations
Oct 12, 2000·Biochemical and Biophysical Research Communications·X HuK S Zuckerman
Oct 16, 1999·Gene·A R Black, J Azizkhan-Clifford
Nov 30, 2013·Cell Death & Disease·B E EngelW D Cress
Dec 19, 2006·Oncogene·Y Ma, W D Cress
Oct 13, 2012·The Journal of Biological Chemistry·Lu ChenW Douglas Cress
Jun 15, 2006·The Journal of Biological Chemistry·Jose M RodriguezW Douglas Cress
Mar 13, 2002·Archives of Biochemistry and Biophysics·Yihong MaW Douglas Cress
Jun 10, 2000·Molecular Biology of the Cell·X ZhangW J Pledger
May 15, 2012·Cell Cycle·Zhen PingDaniele Guardavaccaro
Feb 22, 2002·Oncogene·Rhonda CroxtonW Douglas Cress
Aug 5, 2000·Oncogene·Y HeW D Cress
May 24, 2000·Oncogene·T A Lee, P J Farnham
Mar 16, 2002·Oncogene·Rhonda CroxtonW Douglas Cress
May 1, 2002·The Journal of Biological Chemistry·Yiwen He, W Douglas Cress
Mar 4, 2003·The Journal of Biological Chemistry·Yihong MaW Douglas Cress
Aug 18, 2000·The Journal of Biological Chemistry·W WhartonW J Pledger
Jun 14, 2002·American Journal of Physiology. Heart and Circulatory Physiology·Nobuya FujitaShun Ishibashi