Changes of miR-451 expression during erythroid differentiation of K562 cells / 第二军医大学学报

ABSTRACT

Objective: To observe the expression of miR-451 during erythroid differentiation of K562 cells and investigate the role of miR-451 in erythroid differentiation. Methods: MiR-451 expression was analyzed in different tissues (the liver, bone marrow, erythrocytes, and white blood cells) of mice, human erythrocytes, and chicken red blood cells by Northern blotting. Erythroid differentiation of K562 cells was assessed by DAB staining and RT-PCR of heamoglobin mRNA before and 36 h after hemin induction (50 μmol/L). The expression of miR-451 in K562 cells was further explored by Northern blotting and stem-loop RT-PCR before and 24,48,72,and 96 h after hemin induction (50 μmol/L). Results: Expression of miR-451 was only identified in the erythrocytes, not in white blood cells, hepatic cells or bone marrow of mice. MiR-451 expression was also detected in human erythrocytes and chicken erythrocytes with nuclei. Two bands were detected in the human and mouse erythrocytes by Northern blotting, indicating that, in addition to the one reported by Sanger's miRBase, there was another miR-451 sequence which had additional uracil residue in 3′ terminal. Hemin induced differentiation of K562 cells and DAB staining showed more positive cells after induction (P<0.05); the expression of γ, δ and -̇globin mRNA was also increased after treatment with hemin (P<0.05). Although Northern blotting revealed no changes in miR-451 expression in K562 cells after hemin induction, more sensitive stem-loop RT-PCR showed that miR-451 expression, which maintained at lower level in un-induced K562 cells, was increased during erythroid differentiation 24 h after hemin induction. With the upregulation of δ-globin protein, the expression of miR-451 reached its peak 72 h later. Conclusion: miR-451 is specifically and highly expressed in erythroid terminal differentiation. Two different sequences of miR-415 (one with and additional uracil residue) are present in the human and mouse erythrocytes, and their expression is elevated during the erythroid differentiation of K562 cells.