[Animal ontogenetic cell signaling pathways by the example of Notch cascade of Drosophila melanogaster].

Intercellular communications are coordinated in developing vertebrates and invertebrates embryos by a few signaling pathways. Structural and functional components of the pathways are encoded by cascade of genes. The signal transduction from cell surface to the nucleus is the common feature of these pathways. It is initiated by interaction of secreted ligand (signal) with the outer segment of transmembrane receptor. Then, activation of the intracellular segment of receptor provides modification of signal transducers in cytoplasm including transcription factors that regulates expression of target genes. Cell signal transduction development is conserved between species. In individual organism signal pathways provide various responses due to a time or spatial disjunction of gene expression. Morphogenetic features, genetic structure and signal transduction sequence of events are considered by the example of Notch cascade of Drosophila melanogaster.