Beta minor gene expression is preferentially reduced in EKLF Knock-out mice

The CACCC box is duplicated in the beta-globin gene promoter of humans and other mammals. While the function of the proximal element as a binding site for EKLF has already been well established, the role of the distal element remains unclear. Mice present two adult beta-globin genes, beta-major and beta-minor, bearing a single CACCC box, the consensus sequence of which is identical to that of the proximal or distal human element, respectively. In the present study we analyzed the mRNA expression of beta-minor and beta-major in EKLF Knock-Out (KO) mice in comparison to wild-type (wt) littermates. The murine early fetal liver up to day 13/14 post coitum (pc) expresses mainly beta-minor globin chains. Nevertheless, expression of the beta-minor globin gene in EKLF KO mice has not been assessed to date. We provide evidence that expression of the beta-minor globin gene is dependent upon EKLF and is more affected by EKLF deprivation than the beta-major gene. The results obtained support a general role of EKLF in beta-globin gene activation and are in agreement with models involving an advantage of the LCR proximal respect to distal gene.