Microtubules are essential structures that organize the cytoplasm and form the mitotic spindle. Their number and orientation depend on the rate of nucleation events and their dynamics. Microtubules are often, but not always, nucleated off a single cytoplasmic element, the centrosome. One microtubule-associated protein, XMAP215, is also a resident centrosomal protein. In this study, we have foun...

The effect of removing parts of unfertilized and fertilized eggs of Dentalium has been studied. Up to 70 % of the volume of a 1st polar lobe can be removed from the vegetal side of both unfertilized and fertilized eggs, without influencing apical tuft formation. The post-trochal region is reduced. These eggs form a reduced polar lobe at first cleavage. After removal of more than 70 % of the vol...

Formation of the first cleavage furrow in the telolecithal egg of Loligo was studied with the electron microscope. Before the actual furrow forms, a dense filamentous band develops below the plasma membrane from membrane-bounded dense bodies which appear to be Golgi-derived. The egg surface is thrown into a number of longitudinal folds which parallel the furrow and eventually become incorporate...

The EGF receptor pathway patterns the Drosophila egg and specifies the position of its dorsal appendages. A new mathematical analysis of this patterning network has highlighted its crucial features and provided novel insights into the spatial and temporal kinetics controlling patterning.

This paper describes computational and experimental work on pattern formation in Drosophila egg development (oogenesis), an established experimental model for studying cell fate diversification in developing tissues. Epidermal growth factor receptor (EGFR) is a key regulator of pattern formation and morphogenesis in Drosophila oogenesis. EGFR signalling in oogenesis can be genetically manipulat...

Embryogenesis in the egg of the silkworm. Bombyx mori, up to 24 h after oviposition was studied by light microscopy with special reference to nuclear migration and blastoderm formation. In Bombyx eggs blastoderm cells seem to form in a mechanism different from that usually seen in many other insect species; that is, in Bombyx eggs no typical cleavage furrows were seen. Cleavage nuclei which had...

IN a previous communication (Raven, Escher, Herrebout, & Leussink, 1958) the maturation of the egg was described in Agriolimax reticulatus, Limax flavus, and Limnaea stagnalis, with special regard to the formation of the second maturation spindle. In the three species the second maturation spindle arises by direct transformation from the deep centrosphere of the first maturation amphiaster. In ...