1. Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
2. CNRS, Laboratoire de Spectrometrie Physique, BP87, 38402, St-Martin D'Heres Cedex, France
3. Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
4. Present address: Laboratory of Living Matter, Rockefeller University, 1230 York Avenue, Box 34, New York, New York 10021, USA

Correspondence to: Eric Wieschaus¹ Correspondence and requests for materials should be addressed to E.W. (e-mail: Email: ewieschaus@molbio.princeton.edu).

Abstract

During embryonic development, orderly patterns of gene expression eventually assign each cell in the embryo its particular fate. For the anteroposterior axis of the Drosophila embryo, the first step in this process depends on a spatial gradient of the maternal morphogen Bicoid (Bcd). Positional information of this gradient is transmitted to downstream gap genes, each occupying a well defined spatial domain^{1, 2, 3, 4}. We determined the precision of the initial process by comparing expression domains in different embryos. Here we show that the Bcd gradient displays a high embryo-to-embryo variability, but that this noise in the positional information is strongly decreased ('filtered') at the level of hunchback (hb) gene expression. In contrast to the Bcd gradient, the hb expression pattern already includes the information about the scale of the embryo. We show that genes known to interact directly with Hb are not responsible for its spatial precision, but that the maternal gene staufen may be crucial.

1. Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
2. CNRS, Laboratoire de Spectrometrie Physique, BP87, 38402, St-Martin D'Heres Cedex, France
3. Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
4. Present address: Laboratory of Living Matter, Rockefeller University, 1230 York Avenue, Box 34, New York, New York 10021, USA

Correspondence to: Eric Wieschaus¹ Correspondence and requests for materials should be addressed to E.W. (e-mail: Email: ewieschaus@molbio.princeton.edu).