Consequences of Notch-mediated induction of Jagged1.

Notch signaling is initiated upon contact of cells expressing Notch receptors with those expressing ligands. While examining the dynamic response of NIH 3T3 cells to cells expressing the Notch ligand Jagged1, we found that Notch signaling resulted in increased levels of the ligand Jagged1. Induction of Jagged1 was delayed relative to the generation of active Notch and dependent on the transcription factor p63. The induced Jagged1 had no apparent autocrine effects on Notch signaling but could promote signaling in naïve cells. These results describe a mechanism through which Notch signaling can be relayed from cell to cell.