Abstract: Objective To study the roles of microRNA-144~451 gene cluster during erythroid differentiation of K562 cells. Methods The expression of microRNA-144 and microRNA-451 during K562 erythroid differentiation was detected by quantitative RT-PCR. The occupancy and regulation of transcription factors GATA-1 and EKLF on microRNA-144~451 gene was investigated by chromatin immunoprecipitation (ChIP) and quantitative PCR. K562 cells were transfected with the microRNA-144 or microRNA-451 mimics, respectively. The effects of over-expression of microRNA-144 or microRNA-451 on erythroid differentiation were examined by benzidine staining and quantitative RT-PCR. Western blot was performed to detect the level of erythroid antagonist GATA-2 upon miRNA over-expression. Results microRNA-144 and microRNA-451 were up-regulated during K562 erythroid differentiation. Erythroid transcription factors GATA-1 and EKLF reside and activate microRNA-144~451 gene expression. Over-expression of microRNA-144 or microRNA-451 in K562 cells accelerates its erythroid differentiation. GATA-2 was inhibited by microRNA-144 and microRNA-451 in erythroid cells. Conclusion the microRNA-144~451 gene cluster was activated by GATA-1 and EKLF, and regulated erythroid differentiation of K562 cells via repressing GATA-2.

Key words: microRNA-144, microRNA-451, GATA-1, EKLF, GATA-2