Physical and meiotic mapping of the region of human chromosome 4q11-q13 encompassing the vitamin D binding protein DBP/Gc-globulin and albumin multigene cluster.

The vitamin D binding protein/Gc-globulin (DBP) gene is a member of a multigene cluster that includes albumin (ALB), alpha-fetoprotein (AFP), and alpha-albumin/afamin (AFM). All four genes have structural and functional similarities and map to the same chromosomal regions in humans (4q11-q13), mice, and rats. An accurate physical map of the region encompassing these genes is a prerequisite for study of their respective transcriptional regulation and identification of potential shared regulatory elements. By refining the physical and meiotic maps of the 4q11-q13 region and creating a local PAC contig, the order and transcriptional orientations of these four genes were determined to be centromere-3'-DBP-5'-5'-ALB-3'-5'-AFP-3'-5'-AFM3'-telomere. The ancestral DBP gene was separated from the ALB gene by >1.5 Mb. This organization and spacing establishes a foundation for ongoing functional studies in this region.