Mosaic Analysis in the Drosophila Ovary Reveals a Common Hedgehog-Inducible Precursor Stage for Stalk and Polar Cells

Corresponding author: Hannele Ruohola-Baker, Department of Biochemistry, Box 357350, University of Washington, HSB J-581, 1959 Pacific St., Seattle, WA 98195., hannele{at}u.washington.edu (E-mail)

Communicating editor: T. SCHÜPBACH

The fates of two small subgroups of the ovarian follicle cells appear to be linked: mutations in Notch, Delta, fs(1)Yb, or hedgehog cause simultaneous defects in the specification of stalk cells and polar cells. Both of these subgroups are determined in the germarium, and both cease division early in oogenesis. To test the possibility that these subgroups are related by lineage, we generated dominantly marked mitotic clones in ovaries. Small, restricted clones in stalk cells and polar cells were found adjacent to each other at a frequency much too high to be explained by independent induction. We therefore propose a model in which stalk cells and polar cells are derived from a precursor population that is distinct from the precursors for other follicle cells. We support and extend this model by characterization of mutants that affect stalk and polar cell formation. We find that ectopic expression of Hedgehog can induce both polar and stalk cell fate, presumably by acting on the precursor stage. In contrast, we find that stall affects neither the induction of the precursors nor the decision between the stalk cell and polar cell fate but, rather, some later differentiation step of stalk cells. In addition, we show that ectopic polar and stalk cells disturb the anterior-posterior polarity of the underlying oocyte.

This article has been cited by other articles:

				E. Assa-Kunik, I. L. Torres, E. D. Schejter, D. S. Johnston, and B.-Z. Shilo Drosophila follicle cells are patterned by multiple levels of Notch signaling and antagonism between the Notch and JAK/STAT pathways Development, March 15, 2007; 134(6): 1161 - 1169. [Abstract] [Full Text] [PDF]

				M. Muzzopappa and P. Wappner Multiple roles of the F-box protein Slimb in Drosophila egg chamber development Development, June 1, 2005; 132(11): 2561 - 2571. [Abstract] [Full Text] [PDF]

				J. C. Adam and D. J. Montell A role for extra macrochaetae downstream of Notch in follicle cell differentiation Development, December 1, 2004; 131(23): 5971 - 5980. [Abstract] [Full Text] [PDF]

				S. S. Willard, E. F. Ozdowski, N. A. Jones, and C. Cronmiller stall-Mediated Extrinsic Control of Ovarian Follicle Formation in Drosophila Genetics, September 1, 2004; 168(1): 191 - 198. [Abstract] [Full Text] [PDF]

				H. R. Shcherbata, C. Althauser, S. D. Findley, and H. Ruohola-Baker The mitotic-to-endocycle switch in Drosophila follicle cells is executed by Notch-dependent regulation of G1/S, G2/M and M/G1 cell-cycle transitions Development, July 1, 2004; 131(13): 3169 - 3181. [Abstract] [Full Text] [PDF]

				K. Narbonne, F. Besse, J. Brissard-Zahraoui, A.-M. Pret, and D. Busson polyhomeotic is required for somatic cell proliferation and differentiation during ovarian follicle formation in Drosophila Development, March 15, 2004; 131(6): 1389 - 1400. [Abstract] [Full Text] [PDF]

				M. Grammont and K. D. Irvine Organizer activity of the polar cells during Drosophila oogenesis Development, March 13, 2003; 129(22): 5131 - 5140. [Abstract] [Full Text] [PDF]

				F. Besse and A.-M. Pret Apoptosis-mediated cell death within the ovarian polar cell lineage of Drosophila melanogaster Development, March 1, 2003; 130(5): 1017 - 1027. [Abstract] [Full Text] [PDF]

				F. Besse, D. Busson, and A.-M. Pret Fused-dependent Hedgehog signal transduction is required for somatic cell differentiation during Drosophila egg chamber formation Development, September 1, 2002; 129(17): 4111 - 4124. [Abstract] [Full Text] [PDF]

				J. Bai and D. Montell Eyes Absent, a key repressor of polar cell fate during Drosophila oogenesis Development, January 12, 2002; 129(23): 5377 - 5388. [Abstract] [Full Text] [PDF]

				J. R. McGregor, R. Xi, and D. A. Harrison JAK signaling is somatically required for follicle cell differentiation in Drosophila Development, January 2, 2002; 129(3): 705 - 717. [Abstract] [Full Text] [PDF]

				W.-M. Deng, C. Althauser, and H. Ruohola-Baker Notch-Delta signaling induces a transition from mitotic cell cycle to endocycle in Drosophila follicle cells Development, December 1, 2001; 128(23): 4737 - 4746. [Abstract] [Full Text] [PDF]

				M. Grammont and K. D. Irvine fringe and Notch specify polar cell fate during Drosophila oogenesis Development, June 15, 2001; 128(12): 2243 - 2253. [Abstract] [Full Text] [PDF]

				H. L.-S. a. D. St. Johnston Delta signaling from the germ line controls the proliferation and differentiation of the somatic follicle cells during Drosophila oogenesis Genes & Dev., June 1, 2001; 15(11): 1393 - 1405. [Abstract] [Full Text] [PDF]

				Y. Zhang and D. Kalderon Regulation of cell proliferation and patterning in Drosophila oogenesis by Hedgehog signaling Development, May 15, 2000; 127(10): 2165 - 2176. [Abstract] [PDF]