Hime G, Saint R
Department of Biochemistry, University of Adelaide, South Australia.
Development. 1992 Jan;114(1):165-71. doi: 10.1242/dev.114.1.165.
Mutations at the pebble locus of Drosophila melanogaster result in embryonic lethality. Examination of homozygous mutant embryos at the end of embryogenesis revealed the presence of fewer and larger cells which contained enlarged nuclei. Characterization of the embryonic cell cycles using DAPI, propidium iodide, anti-tubulin and anti-spectrin staining showed that the first thirteen rapid syncytial nuclear divisions proceeded normally in pebble mutant embryos. Following cellularization, the postblastoderm nuclear divisions occurred (mitoses 14, 15 and 16), but cytokinesis was never observed. Multinucleate cells and duplicate mitotic figures were seen within single cells at the time of the cycle 15 mitoses. We conclude that zygotic expression of the pebble gene is required for cytokinesis following cellularization during Drosophila embryogenesis. We postulate that developmental regulation of zygotic transcription of the pebble gene is a consequence of the transition from syncytial to cellular mitoses during cycle 14 of embryogenesis.
果蝇黑腹果蝇卵石基因座的突变会导致胚胎致死。在胚胎发育末期对纯合突变胚胎进行检查，发现细胞数量减少且细胞体积增大，细胞核也增大。使用4',6-二脒基-2-苯基吲哚（DAPI）、碘化丙啶、抗微管蛋白和抗血影蛋白染色对胚胎细胞周期进行表征，结果表明，在卵石突变胚胎中，最初的13次快速合胞体核分裂正常进行。细胞化之后，胚盘后核分裂发生（有丝分裂14、15和16），但从未观察到胞质分裂。在第15次有丝分裂时，在单个细胞内可见多核细胞和重复的有丝分裂图像。我们得出结论，在果蝇胚胎发育过程中，细胞化后的胞质分裂需要卵石基因的合子表达。我们推测，卵石基因合子转录的发育调控是胚胎发育第14周期从合胞体有丝分裂向细胞有丝分裂转变的结果。
