A 6-MB YAC CONTIG IN XP22.1 SPANNING THE DXS69E, XE59, GLRA2, PIGA, GRPR, CALB3, AND PHKA2 GENES

We report the generation of an similar to 6-Mb contig of 70 overlappin g yeast artificial chromosomes (YAC) covering the interval between DXS 16 and DXS1229 in Xp22.1-p22.2. Within this region lie the genes for c albindin (CALB3), gastrin-releasing peptide receptor (GRPR), phosphati dyl-inositol glycan-class A protein (PIGA), glycine receptor alpha-2 ( GLRA2), phosphorylase kinase alpha (PHKA2), XE59 (a gene escaping X ch romosome inactivation), and DXS69E (71-7A). YACs were isolated initial ly from four libraries either by hybridization or using sequence tagge d sites (STSs) for DXS16, DXS9, GLRA2, DXS207, DXS43, DXS1416, DXS1317 , DXS1195, and DXS418. Additional STSs were obtained from the end frag ments of the original YACs studied, thus allowing us to cover the cont ig with a series of 73 STSs, approximately 1 per 100 kb. YAC contig co nstruction allowed the following locus order to be established: Xpter- DXS16-DXS69E-DXS414-XE59-DXS9-(GLRA2, DXS987)-(PIGA, DXS207)-DXS1053-D XS197-(GRPR, ALB3-DXS1416-DXS1317-DXS1195-DXS418-DXS257-(PHKA2, DXS999 )-DXS443-DXS1229-Xcen. Restriction mapping of the DXS16-DXS43 interval predicted the existence of several CpG islands, suggesting the presen ce of other genes in the region. This work provides a starting point f or further mapping and positional cloning of several X-linked disease genes. (C) 1995 Academic Press, Inc.