caa a22 4500 475768027 CHVBK 20180406123611.0 cr unu---uuuuu 170329e20000801xx s 000 0 eng 10.1007/s004270000081 doi (NATIONALLICENCE)springer-10.1007/s004270000081 The Mirror transcription factor links signalling pathways in Drosophila oogenesis [Elektronische Daten] [Debiao Zhao, Sarah Woolner, M. Bownes] Abstract : Many genetic cascades are conserved in evolution, yet they trigger different responses and hence determine different cell fates at specific times and positions in development. At stage 10 of oogenesis, mirror is expressed in anterior-dorsal follicle cells, and we show that this is dependent upon the Gurken signal from the oocyte. The fringe gene is expressed in a complementary pattern in posterior-ventral follicle cells at the same stage. Ectopic expression of mirror represses fringe expression, thus linking the epidermal growth factor receptor (EGFR) signalling pathway to the Fringe signalling pathway via Mirror. The EGFR pathway also triggers the cascade that leads to dorsal-ventral axis determination in the embryo. We used twist as an embryonic marker for ventral cells. Ectopic expression of mirror in the follicle cells during oogenesis ultimately represses twist expression in the embryo, and leads to similar phenotypes to the ectopic expression of the activated form of EGFR. Thus, mirror also controls the Toll signalling pathway, leading to Dorsal nuclear transport. In summary, we show that the Mirror homeodomain protein provides a link that coordinates the Gurken/EGFR signalling pathway (initiated in the oocyte) with the Fringe/Notch/Delta pathway (in follicle cells). This coordination is required for epithelial morphogenesis, and for producing the signal in ventral follicle cells that determines the dorsal/ventral axis of the embryo. Springer-Verlag Berlin Heidelberg, 2000 Key words Cell-signalling nationallicence Oogenesis nationallicence Genetic cascades nationallicence Zhao Debiao Roslin Institute, Roslin, Midlothian EH10 4AN, UK, GB aut Woolner Sarah Institute of Cell and Molecular Biology, University of Edinburgh, Darwin Building, King's Buildings, Edinburgh EH9 3JR, UK e-mail: Mary.Bownes@ed.ac.uk Tel: +44-131-6505369, Fax: +44-131-6508650, GB aut Bownes M. Institute of Cell and Molecular Biology, University of Edinburgh, Darwin Building, King's Buildings, Edinburgh EH9 3JR, UK e-mail: Mary.Bownes@ed.ac.uk Tel: +44-131-6505369, Fax: +44-131-6508650, GB aut https://doi.org/10.1007/s004270000081 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s004270000081 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhao Debiao Roslin Institute, Roslin, Midlothian EH10 4AN, UK, GB aut NATIONALLICENCE 700 1- Woolner Sarah Institute of Cell and Molecular Biology, University of Edinburgh, Darwin Building, King's Buildings, Edinburgh EH9 3JR, UK e-mail: Mary.Bownes@ed.ac.uk Tel: +44-131-6505369, Fax: +44-131-6508650, GB aut NATIONALLICENCE 700 1- Bownes M. Institute of Cell and Molecular Biology, University of Edinburgh, Darwin Building, King's Buildings, Edinburgh EH9 3JR, UK e-mail: Mary.Bownes@ed.ac.uk Tel: +44-131-6505369, Fax: +44-131-6508650, GB aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer