Functional Elements of the Cytoskeleton in the Early Drosophila Embryo

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Synopsis of Early Embryonic Development and Major Features of the Embryonic Cytoskeleton . . . . ... . . .... . .. . .... . .. . . . ....... 68 IDENTIFICATION AND PERTURBATION OF CYTOSKELETAL ELEMENTS . . 72 Biochemical and Molecular Approaches . . . . ....... _ . . . . . . . . . . . . . . 72 Genetic Approaches . .. . . . ... . . . . . .... . .... . .. . . .. . .... . .. 73 Disruption and Modification of the Cytoskeleton by Epigenetic Means. . . . . . . 74 NUCLEAR MIGRATION AND OTHER FORMS OF LARGE SCALE MOTION WITHIN THE CYTOPLASM . . . . . . . . .. . . . . . . . . . . . . . . 75 Nuclear Migration ... . .. . . . . . . . .. . . . . .. . .... . .. . ........ . 76 Motion and Transport of Particles in the Periplasm .. . .. . . . ....... ... 79 DYNAMIC REARRANGEMENTS AT THE CORTEX OF THE SYNCYTIAL BLASTODERM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Correspondence of Surface and Cytoskeletal Dynamics ..... ..... . . ... . 81 Centrosomes as Cytoplasmic Organizers. . . . . . . . . . . . . . . . . . . . . . . . . . 83 CYTOKINESIS . . . . . . . . . . . . . . . : . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Pole Cell Formation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Blastoderm Cellularization . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 CONCLUSION . . ..... . . . . ... . . . . . . . .... . .... . . . .. . ... . . . . 94