TGIF1在红细胞分化中的功能和机制研究

Function and mechanism of TGIF1 in erythroid differentiation

目的筛选潜在的促红系分化因子,并验证其对红系分化的促进作用,探讨促分化机制。方法首先通过对高通量组学测序数据的分析,找到潜在红系调控转录因子;之后在红系分化的细胞模型TF-1细胞系中干扰该因子的表达,观察该因子的异常表达对红系分化的影响;进一步对目的基因敲低的细胞系进行转录组测序,同时利用生物信息学的手段分析受影响的红系相关因子以及通路。结果高通量组学测序分析得到潜在促红系分化调控因子TGIF1。TGIF1敲低细胞中,ε-珠蛋白、γ-珠蛋白、红系特异转录因子(GATA1、KLF1)、以及红系细胞表面特异糖蛋白标志分子CD235a的m RNA表达量及血红蛋白浓度均低于对照组。TGIF1过表达细胞的γ-珠蛋白m RNA高于对照组;促红细胞生成素诱导3天后,TGIF1过表达细胞表面CD235a的表达高于空白细胞组。进一步对稳定敲低TGIF1的TF-1细胞系进行高通量转录组测序分析,发现Smad复合物和相关靶基因表达上调,而GATA1和ALAS2的表达量则降低。结论 TGIF1是一个促红系分化的转录调控因子,可能通过影响转化生长因子β(transforming growth factor-β,TGFβ)通路中Smad复合物和相关靶基因的表达,或通过影响GATA1和ALAS2的表达来调控红系分化过程。

Objective To identify the potential regulator which can promote erythroid differentiation and to validate its function, and to discuss the mechanism of erythroid differentiation. Methods High- throughout RNA-seq data of erythroid cells at different differentiation stages was analyzed to screen potential erythroid transcriptional regulatory factor. Expression of candidate factor was interfered in TF-1 cells to investigate its role in erythroid differentiation. Transcriptome analyses of candidate knockdown TF-1 cells and bioinformatics techniques were performed to correlated erythroid genes and signaling pathways. Results TG1F1 was determined as a potential erythroid transcription factor as its consistent expression along with erythroid differentiation. In the TGIFl-knockdown TF-1 cells, the mRNA expression of e -globin, 3, -globin, erythroid-specific transcription factors such as GATA1 and KLF1, and erythroid-specific cell surface marker such as CD235a were all lower than that in control cells; and so was the hemoglobin concentration. In TGIFl-overexpressed TF-1 cells, the mRNA expression of 3＇ -globin is higher than that in control cells. After three days of induction by erythropoietin, CD235a expression on the surface of TGIFl-overexpressed cellswas higher than that of control cells. The transcriptome analyses of TGIFl-knockdown TF-I cells revealed that the expression of Smad family genes was up-regulated and GATA1 and ALAS2 were two most significant down-regulated genes. Conclusion TGIF1 is an erythroid transcription factor which can promote erythroid differentiation probably by its interference with the expression of Smad family genes or two erythroid genes GATA1 and ALAS2.