Faculty of Industrial Science and Technology, Department of Biological Science and Technology, Tokyo University of Science, Tokyo 125-8585; Genome and Drug Research Center, Tokyo University of Science, Chiba 270-0101.
Faculty of Industrial Science and Technology, Department of Biological Science and Technology, Tokyo University of Science, Tokyo 125-8585.
J Biol Chem. 2013 Jun 7;288(23):16839-16847. doi: 10.1074/jbc.M113.459594. Epub 2013 Apr 22.
Erythropoiesis results from a complex combination of the expression of several transcription factor genes and cytokine signaling. However, the overall view of erythroid differentiation remains unclear. First, we screened for erythroid differentiation-related genes by comparing the expression profiles of high differentiation-inducible and low differentiation-inducible murine erythroleukemia cells. We identified that overexpression of α-1,6-fucosyltransferase (Fut8) inhibits hemoglobin production. FUT8 catalyzes the transfer of a fucose residue to N-linked oligosaccharides on glycoproteins via an α-1,6 linkage, leading to core fucosylation in mammals. Expression of Fut8 was down-regulated during chemically induced differentiation of murine erythroleukemia cells. Additionally, expression of Fut8 was positively regulated by c-Myc and c-Myb, which are known as suppressors of erythroid differentiation. Second, we found that FUT8 is the only fucosyltransferase family member that inhibits hemoglobin production. Functional analysis of FUT8 revealed that the donor substrate-binding domain and a flexible loop play essential roles in inhibition of hemoglobin production. This result clearly demonstrates that core fucosylation inhibits hemoglobin production. Third, FUT8 also inhibited hemoglobin production of human erythroleukemia K562 cells. Finally, a short hairpin RNA study showed that FUT8 down-regulation induced hemoglobin production and increase of transferrin receptor/glycophorin A-positive cells in human erythroleukemia K562 cells. Our findings define FUT8 as a novel factor for hemoglobin production and demonstrate that core fucosylation plays an important role in erythroid differentiation.
红细胞生成是由几个转录因子基因的表达和细胞因子信号的复杂组合产生的。然而，红细胞分化的总体情况仍不清楚。首先，我们通过比较高分化诱导和低分化诱导的小鼠红白血病细胞的表达谱，筛选出与红细胞分化相关的基因。我们发现，α-1,6-岩藻糖基转移酶（Fut8）的过表达抑制血红蛋白的产生。FUT8 通过α-1,6 键将岩藻糖残基转移到糖蛋白的 N-连接寡糖上，导致哺乳动物中的核心岩藻糖基化。在小鼠红白血病细胞的化学诱导分化过程中，Fut8 的表达下调。此外，Fut8 的表达受 c-Myc 和 c-Myb 的正向调节，c-Myc 和 c-Myb 是红细胞分化的抑制因子。其次，我们发现 FUT8 是唯一抑制血红蛋白产生的岩藻糖基转移酶家族成员。FUT8 的功能分析表明，供体底物结合域和柔性环在抑制血红蛋白产生中起重要作用。这一结果清楚地表明核心岩藻糖基化抑制血红蛋白的产生。第三，FUT8 还抑制人红白血病 K562 细胞的血红蛋白产生。最后，短发夹 RNA 研究表明，FUT8 的下调诱导了人红白血病 K562 细胞的血红蛋白产生和转铁蛋白受体/血型糖蛋白 A 阳性细胞的增加。我们的研究结果将 FUT8 定义为血红蛋白产生的一个新的调节因子，并证明核心岩藻糖基化在红细胞分化中起着重要作用。
