This genomic region represents the regulatory region that exists upstream of the mouse alpha-globin gene cluster. It is orthologous to the human alpha-globin locus control region (LCR), which regulates developmental stage- and erythroid lineage-specific expression of the embryonic and adult alpha-globin genes. This region overlaps the Nprl3 (nitrogen permease regulator-like 3) gene, which is transcribed in the opposite orientation compared to the downstream alpha-globin genes, and it also overlaps the 3' end of the Mpg (N-methylpurine-DNA glycosylase) gene. Like the human ortholog, this mouse region is characterized by several DNase I hypersensitive sites (HSs), including the conserved erythroid-specific sites HS-8, HS-21, HS-26 and HS-31. Mouse HS-26 is orthologous to human HS-40, which is the major regulatory element in human. However, unlike human HS-40, mouse HS-26 has relatively weak enhancer activity and does not have LCR activity, suggesting that additional cis-acting elements are necessary for complete developmental regulation of the alpha-globin genes in mice. Five enhancer-like elements, R1, R2, R3, Rm and R4, which correlate with the HSs and/or ATAC-seq accessible sites, are located in this region. Together they constitute a super-enhancer, where each constituent enhancer acts in an additive manner to regulate developmental expression of the alpha-globin genes. Similar to the human counterpart, this mouse upstream regulatory region forms an active chromatin hub based on observed looping interactions with the active alpha-globin genes. [provided by RefSeq, May 2017]