Over the last 20 years, the essential mechanisms of development have become clearer,
mainly because modern molecular genetics has transformed traditional embryology. The …

In multicellular organisms, cells are polarized in the plane of the epithelial sheet, revealed in
some cell types by oriented hairs or cilia. Many of the underlying genes have been identified …

Abstract The Drosophila Notch (N) gene encodes a conserved single-pass transmembrane
receptor that transduces extracellular signals controlling cell fate. Here, we present evidence …

Presenilins are membrane proteins with multiple transmembrane domains that are thought
to contribute to the development of Alzheimer's disease by affecting the processing of β …

Secreted proteins of the Hedgehog (Hh) family have diverse organizing roles in animal
development. Recently, a serpentine protein Smoothened (Smo) has been proposed as a …

Wingless (Wg), a founding member of the Wingless/Int-1 (Wnt) family of secreted proteins,
acts as a short-range inducer and as a long-range organizer during Drosophila …

The adult appendages of Drosophila are formed from imaginal discs, sheets of epithelial
cells that proliferate during larval development and differentiate during metamorphosis …

The bicoid (bcd) protein is expressed in an anteroposterior gradient in early Drosophila
embryos and controls the zygotic activation of the segmentation gene hunchback (hb) in a …

The M-72 gene of C. elegans and the Notch gene of D. melanogaster encode structurally
related transmembrane proteins that mediate Intercellular signaling. We show that truncated …

Abstract Members of the Hedgehog (Hh) and Wnt/Wingless (Wg) families of secreted
proteins control many aspects of growth and patterning during animal development,. Hh …