Abstract: Objective To study the expression profile of transcription factor Sp1 during erythroid differentiation and meanwhile to explore the function of Sp1 on the globin gene expression and erythroid differentaiton. Methods Q-PCR and Western blot were used to detect the expression of Sp1 during erythroid differentiation. Sp1 was knocked down through RNAi in K562 cells which were further checked by Benzidine staining. Q-PCR was performed to measure the hemoglobin expression. FACS was also used to identify the CD71 and CD235a positive cells. Results Both the mRNA and protein level of Sp1 are down-regulated during hemin-induced K562 cell and EPO-induced HPCs (hematopoietic progenitor cells) erythroid differentiation suggesting its negative roles in erythropoiesis. Knock down of Sp1 in K562 cells can improve the expression of ε-, γ-globin, CD71, CD235a and also the hemoglobin-containing cell percentage. Meanwhile, CD71 or CD235a positive cells are also increased in Sp1 down-regulating K562 cells. Conclusions Sp1 is a negative regulator of erythroid differentiation. Knock down of Sp1 in K562 cells can improve the expression of hemoglobin meanwhile accelerate the erythroid differentiation process.

Key words: Sp1, K562 cells, erythroid differentiation