Department of Applied Molecular Chemistry, College of Industrial Technology, Advanced Research Institute for the Sciences and Humanities, Nihon University, Chiba 275-8575.
Dev Growth Differ. 2010 Jan;52(1):43-55. doi: 10.1111/j.1440-169X.2009.01149.x. Epub 2009 Dec 20.
Enchytraeus japonensis is a small oligochaete species that proliferates asexually via fragmentation and regeneration. As sexual reproduction can also be induced, it is a good model system for the study of both regenerative and germline stem cells. It has been shown by histological study that putative mesodermal stem cells called neoblasts, and dedifferentiated epidermal and endodermal cells are involved in blastema formation. Recently, we isolated three region-specific marker genes expressed in the digestive tract and showed by in situ hybridization that morphallactic as well as epimorphic regulation of the body patterning occurs during regeneration. We also cloned two vasa-related genes and analyzed their expression during development and in mature worms that undergo sexual reproduction. The results arising form these studies suggest that the origin and development of germline stem cells and neoblasts may be independent. Furthermore, we carried out functional analysis using RNA interference (RNAi) and showed that a novel gene termed grimp is required for mesodermal cell proliferation at the initial stages of regeneration. These findings indicate that the stem cell system in E. japonensis is regulated by both internal and external environmental factors.
日本盘管虫是一种小型寡毛纲动物，通过分裂和再生进行无性繁殖。由于也可以诱导有性繁殖，因此它是研究再生和生殖干细胞的良好模型系统。组织学研究表明，称为成体干细胞的假定中胚层干细胞，以及去分化的表皮和内胚层细胞参与芽基的形成。最近，我们分离了三个在消化道中表达的区域特异性标记基因，并通过原位杂交显示，在再生过程中发生形态发生和胚后调节的身体模式形成。我们还克隆了两个与 vasa 相关的基因，并分析了它们在发育过程中和进行有性生殖的成熟蠕虫中的表达。这些研究的结果表明，生殖干细胞和成体干细胞的起源和发育可能是独立的。此外，我们使用 RNA 干扰 (RNAi) 进行了功能分析，并表明在再生的初始阶段，一种称为 grimp 的新基因对于中胚层细胞的增殖是必需的。这些发现表明，日本盘管虫的干细胞系统受内部和外部环境因素的调节。
