Expression profiling of prospero mutant VNC cells in Drosophila embryos

Paper abstract: Stem cells have the remarkable ability to give rise to both self-renewing and differentiating daughter cells. Drosophila neural stem cells segregate cell-fate determinants from the self-renewing cell to the differentiating daughter at each division. Here, we show that one such determinant, the homeodomain transcription factor Prospero, regulates the choice between stem cell self-renewal and differentiation. We have identified the in vivo targets of Prospero throughout the entire genome. We show that Prospero represses genes required for self-renewal, such as stem cell fate genes and cell-cycle genes. Surprisingly, Prospero is also required to activate genes for terminal differentiation. We further show that in the absence of Prospero, differentiating daughters revert to a stem cell-like fate: they express markers of self-renewal, exhibit increased proliferation, and fail to differentiate. These results define a blueprint for the transition from stem cell self-renewal to terminal differentiation. 6 wildtype samples and 6 prospero mutant samples were hybridised to arrays against a commom reference sample (generated from whole embryo cDNA). The prospero samples were indirectly compared to the wildtype samples via the common reference. Half the wildtype and half of the prospero arrays were dye-swapped.

论文摘要：干细胞具备卓越的双潜能，既可自我更新，又可产生具有分化潜能的子代细胞。果蝇神经干细胞在每次分裂时，都会将细胞命运决定因子从自我更新的母细胞分选至分化的子代细胞中。在此我们证实，其中一类细胞命运决定因子——同源域转录因子（homeodomain transcription factor）Prospero，可调控干细胞自我更新与分化间的命运抉择。我们已在全基因组范围内鉴定出Prospero的体内靶基因。研究发现，Prospero可抑制自我更新相关基因的表达，例如干细胞命运基因与细胞周期基因。令人意外的是，Prospero同时也是终末分化相关基因激活所必需的。我们进一步证实，当缺失Prospero时，分化的子代细胞会重编程为干细胞样命运：它们会表达自我更新相关标志物，增殖能力增强，且无法完成分化。上述研究结果为干细胞自我更新向终末分化的转变过程构建了清晰的调控蓝图。本研究将6份野生型样本与6份prospero突变体样本，与由全胚胎cDNA制备的通用参照样本进行基因芯片杂交。研究通过该通用参照样本，间接实现了prospero突变体样本与野生型样本间的比较分析。半数野生型芯片与半数prospero突变体芯片进行了荧光染料互换标记。