Butterworth F M, Burde V S, Mauchline D, Bownes M
Oakland University, Rochester, MI, USA.
Tissue Cell. 1999 Apr;31(2):212-22. doi: 10.1054/tice.1999.0022.
The three yolk proteins of Drosophila melanogaster are synthesized in the fat body and ovarian follicle cells. A mutation in yolk protein 3, YP3S1, has been described in which the leader sequence is not cleaved from the protein. We describe here ultrastructural and molecular studies on the YP3S1 mutant and show that the mutant protein enters the secretory pathway and forms precipitates, often as electron dense material in excessive elaborations of the plasma membrane. Females homozygous for YP3S1 lay fewer eggs than wild type flies and these embryos are less viable. The abnormal ultrastructure of the yolk spheres observed suggests that whilst YP3 is not completely essential for viability, it is required for normal yolk sphere morphogenesis.
黑腹果蝇的三种卵黄蛋白在脂肪体和卵巢滤泡细胞中合成。已描述了卵黄蛋白3（YP3S1）中的一种突变，其中前导序列未从该蛋白上切割下来。我们在此描述了对YP3S1突变体的超微结构和分子研究，并表明突变蛋白进入分泌途径并形成沉淀物，通常在质膜过度细化时呈电子致密物质。YP3S1纯合子雌性比野生型果蝇产卵少，并且这些胚胎的活力较低。观察到的卵黄球异常超微结构表明，虽然YP3对生存力并非完全必需，但它是正常卵黄球形态发生所必需的。
