Gu Guoqiang, Brown Juliana R, Melton Douglas A
Department of Molecular and Cell Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA.
Mech Dev. 2003 Jan;120(1):35-43. doi: 10.1016/s0925-4773(02)00330-1.
Lineage tracing follows the progeny of labeled cells through development. This technique identifies precursors of mature cell types in vivo and describes the cell fate restriction steps they undergo in temporal order. In the mouse pancreas, direct cell lineage tracing reveals that Pdx1- expressing progenitors in the early embryo give rise to all pancreatic cells. The progenitors for the mature pancreatic ducts separate from the endocrine/exocrine tissues before E12.5. Expression of Ngn3 and pancreatic polypeptide marks endocrine cell lineages during early embryogenesis, and these cells behave as transient progenitors rather than stem cells. In adults, Ngn3 is expressed within the endocrine islets, and the NGN3+ cells seem to contribute to pancreatic islet renewal. These results indicate the stage at which each progenitor population is restricted to a particular fate and provide markers for isolating progenitors to study their growth, differentiation, and the genes necessary for their development.
谱系追踪通过发育过程追踪标记细胞的后代。这项技术可在体内识别成熟细胞类型的前体细胞，并按时间顺序描述它们所经历的细胞命运限制步骤。在小鼠胰腺中，直接细胞谱系追踪显示，早期胚胎中表达Pdx1的祖细胞可产生所有胰腺细胞。成熟胰管的祖细胞在E12.5之前与内分泌/外分泌组织分离。Ngn3和胰多肽的表达在胚胎早期发育过程中标记内分泌细胞谱系，这些细胞表现为短暂的祖细胞而非干细胞。在成体中，Ngn3在胰岛内表达，NGN3+细胞似乎有助于胰岛更新。这些结果表明了每个祖细胞群体被限制为特定命运的阶段，并提供了用于分离祖细胞以研究其生长、分化及其发育所需基因的标志物。
