PDF(Pubmed)
Abstract：
Along with differences in life histories, metazoans have also evolved vast differences in cellularity, involving changes in the molecular pathways controlling the cell cycle. The extent to which the signalling network systemically determines cellular composition throughout the body and whether tissue cellularity is organized locally to match tissue-specific functions are unclear. We cultured genetic lines of Drosophila melanogaster on food with and without rapamycin to manipulate the activity of target of rapamycin (TOR)/insulin pathways and evaluate cell-size changes in five types of adult cells: wing and leg epidermal cells, ommatidial cells, indirect flight muscle cells and Malpighian tubule epithelial cells. Rapamycin blocks TOR multiprotein complex 1, reducing cell growth, but this effect has been studied in single cell types. As adults, rapamycin-treated flies had smaller bodies and consistently smaller cells in all tissues. Regardless, females eclosed with larger bodies and larger cells in all tissues than males. Thus, differences in TOR activity and sex were associated with the orchestration of cell size throughout the body, leading to differences in body size. We postulate that the activity of TOR/insulin pathways and their effects on cellularity should be considered when investigating the origin of ecological and evolutionary patterns in life histories.
摘要：
随着生活史的不同，后生动物也进化出了巨大的细胞差异，涉及控制细胞周期的分子途径的变化。尚不清楚信号网络在多大程度上系统地确定整个身体的细胞组成，以及组织细胞是否局部组织以匹配组织特异性功能。我们在有或没有雷帕霉素的食物上培养果蝇的遗传系，以操纵雷帕霉素靶（TOR）/胰岛素途径的活性，并评估五种成年细胞的细胞大小变化：翼和腿表皮细胞，网膜细胞，间接飞行肌肉细胞和马尔皮根小管上皮细胞。雷帕霉素阻断TOR多蛋白复合物1，减少细胞生长，但是这种效应已经在单细胞类型中进行了研究。作为成年人,雷帕霉素治疗的苍蝇在所有组织中都有较小的身体和一贯较小的细胞。无论如何,与雄性相比，雌性在所有组织中都有较大的身体和较大的细胞。因此，TOR活性和性别的差异与整个身体细胞大小的编排有关，导致身体大小的差异。我们推测，在研究生活史中生态和进化模式的起源时，应考虑TOR/胰岛素途径的活性及其对细胞数量的影响。
