School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China.
School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China.
Int J Biol Macromol. 2019 Apr 1;126:1050-1055. doi: 10.1016/j.ijbiomac.2019.01.014. Epub 2019 Jan 4.
Nucleocytoplasmic transport is essential for normal cellular function that mediates cargo transport from the cytoplasm to the nucleus. However, the mechanisms of nucleocytoplasmic transport that integrate stem cell development remain largely unknown. Since it has a large population of stem cells, the planarian flatworm is an ideal system for the study of adult stem cell lineage development in vivo. Here, we focus on exportin-1, which is the most conserved nuclear export receptor. Homologs of exportin-1 have no currently known role in stem cell biology. RNA interference targeting exportin-1 caused a failure in anterior and posterior regeneration, and resulted in curly and lysis phenotypes in both intact and regenerating flatworms. During the course of exportin-1 RNAi phenotype, cell division was significantly decreased, and the expression of the epidermal cell markers (vimentin and laminB) were lost from the intact body. Additionally, the expression levels of the neoblast marker piwiA decreased. By contrast, the expression levels of the epidermal progenitor markers NB21.11e and AGAT1 increased. These results suggest that exportin-1 is required for the maintenance of the epidermal lineage in planarians. Inhibition of exportin-1 could promote the premature differentiation of neoblasts to the epidermal lineages, disrupting the proper epidermal maturation.
核质转运对于正常的细胞功能至关重要，它介导了细胞质到细胞核的货物运输。然而，将核质转运机制整合到干细胞发育中仍然在很大程度上是未知的。由于其具有大量的干细胞，扁形动物涡虫是研究体内成体干细胞谱系发育的理想系统。在这里，我们专注于输出蛋白 1（exportin-1），它是最保守的核输出受体。exportin-1 的同源物在干细胞生物学中目前没有已知的作用。靶向 exportin-1 的 RNA 干扰导致了前后再生的失败，并导致完整和再生的扁形动物出现卷曲和裂解表型。在 exportin-1 RNAi 表型的过程中，细胞分裂显著减少，表皮细胞标记物（波形蛋白和 laminB）的表达从完整的身体中丢失。此外，neoblast 标记物 piwiA 的表达水平下降。相比之下，表皮祖细胞标记物 NB21.11e 和 AGAT1 的表达水平增加。这些结果表明，exportin-1 对于维持扁形动物的表皮谱系是必需的。抑制 exportin-1 可能会促进 neoblast 过早分化为表皮谱系，破坏适当的表皮成熟。
