Multiple Ras signals pattern the Drosophila ovarian follicle cells

Dev Biol. 1997 May 1;185(1):25-33. doi: 10.1006/dbio.1997.8537.


During Drosophila oogenesis, spatially restricted activity of the TORPEDO receptor tyrosine kinase first recruits follicle cells adjacent to the oocyte to a posterior cell fate and then specifies dorsal follicle cells. Another receptor tyrosine kinase, BREATHLESS, stimulates migration of the anterior follicle cells known as border cells. Since Ras is known to mediate many receptor tyrosine kinase effects, we have investigated the role of Ras in follicle cell fate determination, differentiation, and migration throughout oogenesis. Early ectopic Ras activity induced transient expression of posterior follicle cell markers in anterior follicle cells, but did not inhibit anterior differentiation. Later ectopic Ras activity inhibited anterior follicle cell differentiation but did not induce posterior marker expression. Complete transformation of anterior follicle cells to posterior follicle cells required early ectopic Ras activity in egg chambers where terminal differentiation of anterior cells was inhibited. These results suggest that, in vivo as in vitro, Ras can have diverse effects on different cells, but, in addition, Ras activity can have different effects on the same cells at different stages in their development.

Publication types

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

MeSH terms

  • Animals
  • CCAAT-Enhancer-Binding Proteins
  • Cell Lineage*
  • DNA-Binding Proteins / physiology
  • Drosophila / embryology*
  • Embryonic Induction
  • Female
  • Nuclear Proteins / physiology
  • Ovarian Follicle / cytology
  • Ovarian Follicle / embryology*
  • Signal Transduction
  • ras Proteins / metabolism
  • ras Proteins / physiology*


  • CCAAT-Enhancer-Binding Proteins
  • DNA-Binding Proteins
  • Nuclear Proteins
  • ras Proteins