Lin28调节小鼠胚胎干细胞向原始生殖细胞分化

The role of Lin28 regulation for mouse embryonic stem cells differentiating into primordial germ cells

目的探讨小鼠胚胎干细胞（mouse embryonic stem cells，mESCs）向原始生殖细胞（primordial germcells，PGCs）分化过程中特异基因表达变化及可能机制。方法mESCs分化形成拟胚体（embryoid bodies，EBS），不同浓度atRA（1uM，2uM，5uM）持续诱导EBS16h、2d和5d，RT—PCR、和免疫荧光分别检测Lin28和Blimpl以及相应蛋白的表达变化。结果atRA诱导16h的EBs其Lin28mRNA表达量较高，随着诱导时间延长而逐渐降低，Blimpl则无明显变化。WB结果显示EBs的Lin28蛋白表达随诱导时间延长逐渐减弱，而Blimpl蛋白表达逐渐增强。免疫荧光显示Lin28和Blimpl阳性信号均定位于细胞胞浆，其变化特点与WB结果相一致。结论EBs经atRA诱导后可影响Lin28的表达，Lin28和Blimpl的变化并不协调，其蛋白表达随着诱导会随之发生变化。atRA诱导可能使PGCs分化的Lin28低水平表达时期提前出现。

Objective To investigate the expression characteristics and mechanism of Lin28 and Blimpl when the mouse embryonic stem cells（mESCs） differentiate into primordial germ cells（PGCs） induced with atRA in vitro. Methods mESCs-derived EBs were maintained in culture medium containing 1 uM, 2 uM and 5 uM atRA for 16h, 2d and 5d, respectively. Real-time PCR, Western blot （WB） and immunofluorescence were performed to detect the expression changes of Lin28 and Blimpl in mESCs-EBs. Results The expression features of genes were showed that Lin28 mRNA rapidly reached peak value in 16h, and gradually decreased with atRA induction, but Blimpl indicated relatively unchanged. WB results were indicated that Lin28 protein expression gradually decreased when the EBs induced with atRA from 16h to 5d. In contrast, Blimpl expression increased when the EBs induced with atRA from 16h to 5d. Immunofluorescence analysis were showed that positive signals of Lin28 and Blimp1 were located in the cytoplasm, and the expression changes were consistent with the WB results. Conclusion The Lin28 expression can be affected when the EBs induced With atRA. The changes of Lin28 and Blimpl are not coordinated. The stage of Lin28 low-expression on PGCs differentiation may occur earlier when the EBs induced.with atRA.