Antagonistic action of Bicoid and the repressor Capicua determines the spatial limits of Drosophila head gene expression domains.

ABSTRACT: Bicoid (Bcd) is the anterior determinant in Drosophila. Accordingly, loss of Bcd causes loss of head and thorax and their replacement with posterior structures. bcd mRNA is maternally deposited at the anterior pole and Bcd forms an anterior-to-posterior (AP) concentration gradient. The expression of a series of zygotic head genes is thought to be differentially regulated by distinct threshold concentrations of the Bcd gradient. Thereby Bcd functions as a morphogen, instructing fields of cells to take on specific fates. Here, we show that spatial limits of anterior genes are also set in the absence of a Bcd gradient and depend on factors of the maternal terminal system. The receptor tyrosine kinase Torso (Tor), a key component of this system, is active in the pole regions of the embryo. Its

SUBMITTER: Lohr U 

PROVIDER: S-EPMC2788481 | biostudies-literature | 2009 Dec

REPOSITORIES: biostudies-literature