PREMATURE MICROTUBULE-DEPENDENT CYTOPLASMIC STREAMING IN CAPPUCCINO AND SPIRE MUTANT OOCYTES

Embryonic axis specification in Drosophila melanogaster is achieved th rough the asymmetric subcellular localization of morphogenetic molecul es within the oocyte. The cappuccino and spire loci are required for b oth posterior and dorsoventral patterning. Time-lapse confocal microsc opic analyses of living egg chambers demonstrated that these mutations induce microtubule reorganization and the premature initiation of mic rotubule-dependent ooplasmic streaming. As a result, microtubule organ ization is altered and bulk ooplasm rapidly streams during the develop mental stages in which morphogens are normally localized. These change s in oocyte cytoarchitecture and dynamics appear to disrupt axial patt erning of the embryo.