bicoid and the terminal system activate tailless expression in the early Drosophila embryo.

摘要: In the early Drosophila embryo, maternal terminal genes are required for formation of acron at anterior and telson posterior. We show here that system, a signal transduction pathway active poles is to activate transcription key zygotic gene tailless (tll) in two symmetrical domains. Consistent with characterization tll protein as putative factor (a member steroid receptor superfamily) represses segmentation activates terminal-specific genes, we observe correlation between presence posterior cap expression differentiation telson. While patterning systems embryo function most part independently, which bicoid (bcd) functions graded morphogen, together system establish acron. This dual requirement evident molecular level control expression. find bcd anterior-dorsal stripe correlated absence bcd, established by persists an ectopic forms anterior, while activity only abnormal forms. first described example how, jointly controlling same gene, positional information set unique values.