雖然人們研究活性氧（ROS）主要是由於它們在DNA損傷、蛋白/類脂氧化和細胞凋亡中的有害作用，但人們也不斷認識到ROS在一些組織中可能有有益作用。在哺乳動物造血系統中，造血幹細胞含有低濃度ROS，但出乎意料的是，「共同髓系祖細胞」（ CMP）產生濃度相當高的ROS。
Edward Owusu-Ansah和Utpal Banerjee在果蠅的兩個先祖細胞類型中，發現了ROS含量的這種差別在功能上的明顯重要性。他們發現，先祖細胞中由發育調控的、比較高的ROS含量使它們對分化比較敏感，並且確立了ROS在調控造血幹細胞命運中所起的信號作用。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 461, 537-541 (24 September 2009) | doi:10.1038/nature08313
Reactive oxygen species prime Drosophila haematopoietic progenitors for differentiation
Edward Owusu-Ansah1,5 & Utpal Banerjee1,2,3,4
1 Department of Molecular, Cell and Developmental Biology,
2 Molecular Biology Institute,
3 Department of Biological Chemistry,
4 Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, California 90095, USA
5 Present address: Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
6 Correspondence to: Utpal Banerjee1,2,3,4 Correspondence and requests for materials should be addressed to U.B.
Reactive oxygen species (ROS), produced during various electron transfer reactions in vivo, are generally considered to be deleterious to cells1. In the mammalian haematopoietic system, haematopoietic stem cells contain low levels of ROS. However, unexpectedly, the common myeloid progenitors (CMPs) produce significantly increased levels of ROS2. The functional significance of this difference in ROS level in the two progenitor types remains unresolved2, 3. Here we show that Drosophila multipotent haematopoietic progenitors, which are largely akin to the mammalian myeloid progenitors4, display increased levels of ROS under in vivo physiological conditions, which are downregulated on differentiation. Scavenging the ROS from these haematopoietic progenitors by using in vivo genetic tools retards their differentiation into mature blood cells. Conversely, increasing the haematopoietic progenitor ROS beyond their basal level triggers precocious differentiation into all three mature blood cell types found in Drosophila, through a signalling pathway that involves JNK and FoxO activation as well as Polycomb downregulation. We conclude that the developmentally regulated, moderately high ROS level in the progenitor population sensitizes them to differentiation, and establishes a signalling role for ROS in the regulation of haematopoietic cell fate. Our results lead to a model that could be extended to reveal a probable signalling role for ROS in the differentiation of CMPs in mammalian haematopoietic development and oxidative stress response.