Ectopic E2F expression induces S phase and apoptosis in Drosophila imaginal discs.


Journal Article

Previous experiments suggest that a key event in the commitment of cultured mammalian cells to entering S phase is a rise in activity of the transcription factor E2F. In this report, we study the role of Drosophila E2F in imaginal disc cells in vivo, by examining the distribution of the endogenous protein and studying the consequences of ectopic E2F expression. First, we find that endogenous E217 falls from high to very low levels as cells initiate DNA synthesis during a developmentally regulated G1-S-transition in the eye disc. Second, we find that ectopic E2F expression drives many otherwise quiescent cells to enter S phase. Subsequently, cells throughout the discs express reaper (a regulator of apoptosis) and then die. Third, we find that ectopic E2F expression during S phase in normally cycling cells blocks their re-entry into S phase in the following cell cycle. Although we do not know the fate of these cells, we suspect that ultimately they are killed by ectopic E2F. Taken together, our results show that an elevation in the level of E2F is sufficient to induce imaginal disc cells to enter S phase. Furthermore, they suggest that the downregulation of E2F upon entry into S phase may be essential to prevent the induction of apoptosis.

Full Text

Cited Authors

  • Asano, M; Nevins, JR; Wharton, RP

Published Date

  • June 1996

Published In

Volume / Issue

  • 10 / 11

Start / End Page

  • 1422 - 1432

PubMed ID

  • 8647438

Pubmed Central ID

  • 8647438

Electronic International Standard Serial Number (EISSN)

  • 1549-5477

International Standard Serial Number (ISSN)

  • 0890-9369

Digital Object Identifier (DOI)

  • 10.1101/gad.10.11.1422


  • eng