Localization and characterization of the mouse alpha-globin locus control region.

The control of the expression of the alpha- and beta-globin gene clusters is effected by sequences called locus control regions (LCRs). Detailed analysis of these elements is therefore essential to the understanding of the complex mechanisms of globin gene regulation. In this paper we describe the characterization of the mouse alpha-globin LCR. This element is localized 26 kb upstream of the mouse embryonic globin gene (Hba-x) and is highly conserved at the protein binding sites. However, three of four CACC boxes and one GATA-1 binding site, identified in the human alpha-LCR, are not conserved in the mouse. Interestingly, we identified a highly conserved putative transcription factor binding sequence (AAAGG) that may play an important role in LCR function. The identification of the mouse alpha-LCR makes it now possible to analyze this element in its natural environment and will certainly contribute to the understanding of the alpha-globin gene expression.