A study of the effect of locus control region elements HS2 and HS3 on beta-globin gene expression

HS2 and HS3 are important elements of human beta-globin locus control region (LCR). To study the effect of HS2, HS3, and HS2-HS3 on human beta-globin gene expression, a series of expression cassettes were constructed, in which the reporter gene encoding the enhanced green fluorescent protein (EGFP) was driven by the beta-globin promotor and under the control of HS2, HS3, and HS2-HS3. These constructs were transfected transiently into MEL and K562 cell lines mediated with liposome and their expression was measured with FACS as well as semi-quantitative RT-PCR method. The results showed that 3.2-kb HS2 could significantly enhance the activity of beta-globin promotor in MEL and K562 cells, while 3-kb HS3 could do only in MEL cells. There was no synergistic function in transient expression in the cassettes with the combination of HS2 and HS3 in MEL and K562 cells.