Howard Hughes Medical Institute, MIT Biology, Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA.
Development. 2013 Mar;140(5):951-7. doi: 10.1242/dev.080499.
Planarians are flatworms capable of regenerating all body parts. Planarian regeneration requires neoblasts, a population of dividing cells that has been studied for over a century. Neoblast progeny generate new cells of blastemas, which are the regenerative outgrowths at wounds. If the neoblasts comprise a uniform population of cells during regeneration (e.g. they are all uncommitted and pluripotent), then specialization of new cell types should occur in multipotent, non-dividing neoblast progeny cells. By contrast, recent data indicate that some neoblasts express lineage-specific transcription factors during regeneration and in uninjured animals. These observations raise the possibility that an important early step in planarian regeneration is the specialization of neoblasts to produce specified rather than naïve blastema cells.
涡虫是一种能够再生所有身体部位的扁形动物。涡虫的再生需要成体干细胞，这是一个已经研究了一个多世纪的分裂细胞群体。成体干细胞的后代产生新的芽基细胞，这些细胞是伤口处的再生突起。如果成体干细胞在再生过程中构成一个均匀的细胞群体（例如，它们都是未分化的多能性细胞），那么新细胞类型的特化应该发生在多能性、不分裂的成体干细胞后代细胞中。相比之下，最近的数据表明，在再生过程中和未受伤的动物中，一些成体干细胞表达谱系特异性转录因子。这些观察结果提出了一种可能性，即在涡虫再生的早期阶段，一个重要的步骤是成体干细胞的特化，以产生特定的而不是幼稚的芽基细胞。
