Expression of zinc finger and homeobox 2 in erythroleukaemic cells and gamma-globin expression

During the last few decades, foetal haemoglobin reactivation has been considered as a promising intervention to treat beta-thalassaemia and sickle-cell anaemia. Variable foetal haemoglobin (Hb F, alpha(2)gamma(2)) production among individuals is under control of distinct chromosome regions, namely, the quantitative trait loci (QTL). One of the QTL affecting Hb F levels on chromosome 8q has never been explored. The zinc fingers and homeodomains 2 (ZHX2) transcription factor located at 8q position is remarkably down-regulated in hereditary persistence of foetal haemoglobin, indicating an inverse correlation between the gamma-globin and ZHX2 expression. Here we studied the effect of ZHX2 over the gamma-globin expression in K562 erythroleukaemic cell line by transient transfection with a ZHX2 expression plasmid. At 24 h after transfection, the relative expression of endogenous gamma-globin mRNA had been reduced to 0.401 +/- 0.08 as assessed by real-time PCR. Our finding suggests that the repressive effect on gamma-globin probably results from the presence of ZHX2 and supports its possible involvement in the regulation of gamma-globin expression.