Characterization of a mouse laminin receptor gene homologous to the human blood group Lutheran gene

The human Lutheran (Lu) blood group antigens are carried by two glycoprotei ns (gps) that belong to the immunoglobulin (Ig) superfamily. These gps repr esent adhesion molecules that function as the unique erythroid receptors fo r laminin. We report here the cloning and functional expression of the orth ologous mouse Ln mRNA as well as the genomic organization of the mouse Lu g ene. The deduced human and mouse Lu gps share 72.5% identity and similar or ganization of the Ig-like domains. As in the human, the mouse Lu gene is or ganized in 15 exons. The proximal promoter showed consensus CACC-binding si tes whereas the distal promoter exhibits a GATA-1-binding site and multiple E boxes. Like the human gene, the mouse Lu gene is also widely expressed a mong tissues but is transcribed as a unique 2.4-kb mRNA species. Expression of the mouse Lu mRNA is upregulated upon dimethyl sulfoxide-induced erythr oid differentiation of murine erythroleukemia cells (MEL). During mouse emb ryonic development, the Lu transcript is detected as early as day 7 of gest ation. Analysis of transfected human erythroleukemia K562 cells indicated t hat the adhesive properties of the Lu gps to laminin are conserved between human and mouse.