@article{78ee03fbeee74d9195f4be46cf72bdb9,
title = "Down-regulation of the Drosophila morphogen bicoid by the torso receptor-mediated signal transduction cascade",
abstract = "Anterior body pattern in Drosophila is specified by the graded distribution of the bicoid protein (bcd), which activates subordinate genes in distinct anterior domains. Subsequently, transcription of these target genes is repressed at the anterior pole owing to the activity of the receptor tyrosine kinase torso (tor). We show that both activation by bcd and repression by tor can be reproduced by a minimal promoter containing only bcd-binding sites upstream of a naive transcriptional start site. Repression requires the D-raf kinase and is associated with phosphorylation of bcd protein. Repression does not require either tailless or huckebein, which were previously thought to constitute the sole zygotic output of the tor signaling system. Finally, addition of a heterologous transcriptional activation domain to bcd renders the protein insensitive to tormediated repression. We propose that phosphorylation resulting from the activity of the tor signal transduction cascade down-regulates transcriptional activation by the bcd morphogen.",
author = "E. Ronch and J. Treisman and N. Dostatni and G. Struhl and C. Desplan",
note = "Funding Information: The first three authors contributed equally to this work. Correspondence should be addressed to C. D. We are very grateful to B. and 8. Cohen for continuous support and for help with head cuticle analysis and with the manuscript; to T.-B. Chou and N. Perrimon for helpful discussions and for providing us with the FRTsystem; to R. Finkelstein, A. Brand, and N. Perrimon for their encouragement at the beginning of the work; and to W. Driever for constant support and for providing us with many of the tools used in this study. Y. Bellarche was very helpful for the immunoprecipitation and Western blot experiments and was involved in many fruitful discussions. We also want to thank H. Jackie forchallenging discussions: F. Pignoni and J. Lengyelfor stocks and results prior to publication; D. Dorsett for help with cell culture; and M. and K. Blake for help with the Western blot analysis. R. Burzyn-ski and the Rockefeller Media Center were very helpful for the computer processing of the figures. Finally, this work was only possible because of the stimulating environment of S. DiNardo and his lab along with the members of the Desplan lab, who all provided continuous support and helpful comments on the work and on the manuscript. J. T. was supported in part by the Lucy Markey Charitable Fund. N. D. is supported by a fellowship from the Human Frontier Program. This work was supported by the Howard Hughes Medical Institute.",
year = "1993",
month = jul,
day = "30",
doi = "10.1016/0092-8674(93)90425-P",
language = "English (US)",
volume = "74",
pages = "347--355",
journal = "Cell",
issn = "0092-8674",
publisher = "Elsevier B.V.",
number = "2",
}