Overexpression of p21waf1/cip1 arrests the growth of chicken embryo fibroblasts that overexpress E2F1

Oncogene. 1998 Jun 18;16(24):3115-22. doi: 10.1038/sj.onc.1201849.


P21waf1/cip1 is a potent inhibitor of cell cycle progression and can inhibit the growth of both normal cells and cells transformed by a number of oncogenes. However, the ability of p21waf1/cip1 to inhibit the growth of cells that overexpress the transcriptional transactivator E2F1 is controversial: it has been reported both that E2F1 can and cannot overcome the block in the cell cycle induced by p21waf1/cip1. To avoid the complications that arise when such experiments are done with permanent cell lines, we tested the effects of overexpressing p21waf/cip1 and E2F1 in primary chicken embryo fibroblasts. In this system very high levels of E2F1 overexpression cause considerable apoptosis; however, the surviving cells still overexpress E2F1. These cells are transformed and their growth is blocked by overexpression of p21waf1/cip1.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Carrier Proteins*
  • Cell Cycle Proteins*
  • Cell Division / genetics*
  • Cell Line, Transformed
  • Chick Embryo
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins / genetics*
  • DNA-Binding Proteins*
  • E2F Transcription Factors
  • E2F1 Transcription Factor
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • G1 Phase / genetics
  • Genetic Vectors
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Retinoblastoma-Binding Protein 1
  • Retroviridae / genetics
  • Transcription Factors / genetics*


  • Carrier Proteins
  • Cell Cycle Proteins
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • DNA-Binding Proteins
  • E2F Transcription Factors
  • E2F1 Transcription Factor
  • Proto-Oncogene Proteins c-bcl-2
  • Retinoblastoma-Binding Protein 1
  • Transcription Factors