... for transcriptional regulation of Notch and/or Delta during neuroblast segregation in embryos, by providing Notch and Delta ubiquitously at uniform levels. Neuroblast segregation occurs normally under conditions of uniform Notch expression. Under conditions of uniform Delta expression, a single neuroblast segregates...

... or antagonistic to those proposed for the putative NOTCH ligand DELTA. Our results demonstrate that Serrate can replace Delta gene function during embryonic neuroblast segregation and that expression of Serrate leads to a NOTCH-dependent suppression of achaete expression in proneural clusters. Our findings...

... neuroblast row through regulatory elements located 3′ to ac ; second, through a 5′ regulatory region, vnd functions to increase or maintain proneural gene expression in the cell within the proneural cluster that normally becomes the neuroblast. By following neuroblast segregation in vnd mutant embryos, we...

... of peripheral sensory organs in imaginai epithelia. The groups appear in different regions of the neuroectoderm, accompanying the three successive waves of neuroblast segregation. Most neuroblasts delaminate from these clusters and express position-specific levels of 1’sc protein. No significant differences...