Nuclear Signalling Lab., Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
Australian Regenerative Medicine Institute, Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia.
Biochem Biophys Res Commun. 2021 Jan 1;534:141-148. doi: 10.1016/j.bbrc.2020.11.099. Epub 2020 Dec 15.
Nuclear transporter Importin (Imp, Ipo) 13 is known to transport various mammalian cargoes into/out of the nucleus, but its role in directing cell-fate is unclear. Here we examine the role of Imp13 in the maintenance of pluripotency and differentiation of embryonic stem cells (ESCs) for the first time, using an embryonic body (EB)-based model. When induced to differentiate, Ipo13 ESCs displayed slow proliferation, reduced EB size, and lower expression of the proliferation marker KI67, concomitant with an increase in the number of TUNEL nuclei compared to wildtype ESCs. At days 5 and 10 of differentiation, Ipo13 EBs also showed enhanced loss of the pluripotency transcript OCT3/4, and barely detectable clusters of OCT3/4 positive cells. Day 5 Ipo13 EBs further exhibited reduced levels of the mesodermal markers Brachyury and Mixl1, correlating with reduced numbers of haemoglobinised cells generated. Our findings suggest that Imp13 is critical to ESC survival as well as early post-gastrulation differentiation.
核转运蛋白 Importin (Imp, Ipo) 13 已知可将各种哺乳动物货物运进/出细胞核，但它在指导细胞命运方面的作用尚不清楚。在这里，我们首次使用胚胎体 (EB) 模型研究了 Imp13 在维持胚胎干细胞 (ESC) 多能性和分化中的作用。在诱导分化时，Ipo13 ESC 表现出增殖缓慢、EB 体积减小以及增殖标记物 KI67 的表达降低，与野生型 ESC 相比，TUNEL 核的数量增加。在分化的第 5 天和第 10 天，Ipo13 EB 还表现出多能性转录因子 OCT3/4 的表达丢失增加，几乎检测不到 OCT3/4 阳性细胞簇。第 5 天的 Ipo13 EB 进一步表现出中胚层标记物 Brachyury 和 Mixl1 的水平降低，与生成的血红蛋白化细胞数量减少相关。我们的研究结果表明，Imp13 对于 ESC 的存活以及原肠胚后早期分化至关重要。
