QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online March 1, 2007
doi: 10.1242/10.1242/dev.02800

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Assa-Kunik, E. Articles by Shilo, B.-Z. Search for Related Content PubMed PubMed Citation Articles by Assa-Kunik, E. Articles by Shilo, B.-Z.

Drosophila follicle cells are patterned by multiple levels of Notch signaling and antagonism between the Notch and JAK/STAT pathways

Efrat Assa-Kunik^1,*, Isabel L. Torres^2,*, Eyal D. Schejter^1,, Daniel St Johnston² and Ben-Zion Shilo^1,

¹ Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
² The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK.

Authors for correspondence (e-mail: Eyal.schejter{at}weizmann.ac.il; benny.shilo{at}weizmann.ac.il)

Accepted 4 January 2007

The specification of polar, main-body and stalk follicle cells in the germarium of the Drosophila ovary plays a key role in the formation of the egg chamber and polarisation of its anterior-posterior axis. High levels of Notch pathway activation, resulting from a germline Delta ligand signal, induce polar cells. Here we show that low Notch activation levels, originating from Delta expressed in the polar follicle cells, are required for stalk formation. The metalloprotease Kuzbanian-like, which cleaves and inactivates Delta, reduces the level of Delta signaling between follicle cells, thereby limiting the size of the stalk. We find that Notch activation is required in a continuous fashion to maintain the polar and stalk cell fates. We further demonstrate that mutual antagonism between the Notch and JAK/STAT signaling pathways provides a crucial facet of follicle cell patterning. Notch signaling in polar and main-body follicle cells inhibits JAK/STAT signaling by preventing STAT nuclear translocation, thereby restricting the influence of this pathway to stalk cells. Conversely, signaling by JAK/STAT reduces Notch signaling in the stalk. Thus, variations in the levels of Notch pathway activation, coupled with a continuous balance between the Notch and JAK/STAT pathways, specify the identity of the different follicle cell types and help establish the polarity of the egg chamber.

Key words: Notch, Delta, JAK/STAT, Unpaired, Follicle cells, Oogenesis, Kuzbanian-like (Kul)

This article has been cited by other articles:

				J. Sun, L. Smith, A. Armento, and W.-M. Deng Regulation of the endocycle/gene amplification switch by Notch and ecdysone signaling J. Cell Biol., September 8, 2008; 182(5): 885 - 896. [Abstract] [Full Text] [PDF]