Genetic control of determination in the Drosophila embryo

Intracellular cleavage of Notch leads to a heterodimeric receptor on the plasma membrane

Previous models for signal transduction via the Notch pathway have depicted the full-length Notch receptor expressed at the cell surface. We present evidence demonstrating that the Notch receptor on the plasma membrane is cleaved. This cleavage is an evolutionarily conserved, general property of Notch and occurs in the trans-Golgi network as the receptor traffics toward the plasma membrane. Although full-length Notch is detectable in the cell, it does not reach the surface. Cleavage results in a C-terminal fragment, N(TM), that appears to be cleaved N-terminal to the transmembrane domain, and an N-terminal fragment, N(EC), that contains most of the extracellular region. We provide evidence that these fragments are tethered together on the plasma membrane by a link that is sensitive to reducing conditions, forming a heterodimeric receptor.

The Leeuwenhoek Lecture, 1977. Mouse teratocarcinoma and mouse embryo

Biochemical and immunological investigations of the early mammalian embryonic development are hampered by the scarcity and the heterogeneity of the material. It is possible to get round some of these difficulties by the use of mouse teratocarcinoma as a model system for studying certain aspects of cellular differentiation.

A dicephalic monster embryo ofDrosophila melanogaster

/Binsn female. The embryo probably represents a longitudinal mirror duplication of head and all 3 thoracic segments. The significance of this type of pattern anomaly for embryonic pattern specification inDrosophila is discussed.