Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America.
PLoS One. 2011;6(10):e26410. doi: 10.1371/journal.pone.0026410. Epub 2011 Oct 19.
Lifelong, many somatic tissues are replenished by specialized adult stem cells. These stem cells are generally rare, infrequently dividing, occupy a unique niche, and can rapidly respond to injury to maintain a steady tissue size. Despite these commonalities, few shared regulatory mechanisms have been identified. Here, we scrutinized data comparing genes expressed in murine long-term hematopoietic stem cells with their differentiated counterparts and observed that a disproportionate number were members of the developmentally-important, monoallelically expressed imprinted genes. Studying a subset, which are members of a purported imprinted gene network (IGN), we found their expression in HSCs rapidly altered upon hematopoietic perturbations. These imprinted genes were also predominantly expressed in stem/progenitor cells of the adult epidermis and skeletal muscle in mice, relative to their differentiated counterparts. The parallel down-regulation of these genes postnatally in response to proliferation and differentiation suggests that the IGN could play a mechanistic role in both cell growth and tissue homeostasis.
在整个生命周期中，许多体组织都由专门的成人干细胞来补充。这些干细胞通常数量稀少，分裂频率低，占据独特的生态位，可以快速响应损伤以维持稳定的组织大小。尽管存在这些共性，但很少有共同的调节机制被发现。在这里，我们仔细研究了比较小鼠长期造血干细胞与其分化对应物表达的基因的数据，观察到不成比例数量的基因是发育重要的、单等位基因表达的印迹基因。研究了一组被认为是印迹基因网络 (IGN) 的成员，我们发现它们在造血扰动后迅速改变 HSCs 的表达。与分化对应物相比，这些印迹基因在成年表皮和骨骼肌的干细胞/祖细胞中也主要表达。这些基因在出生后响应增殖和分化而平行地下调，表明 IGN 可能在细胞生长和组织稳态中发挥机制作用。
