DIRECT MAPPING OF 7 GENES ENCODING HUMAN TYPE-2 CYSTATINS TO A SINGLE-SITE LOCATED AT 20P11.2

The human type 2 cystatins are encoded by a multigene family of eight to nine members. Five functional genes (CST1-CST5) and two pseudogenes (CSTP1 and CSTP2) have previously been cloned. me have developed a pa nel of short genomic fragments that serve as gene-specific probes for these seven genes under hybridization conditions used for Southern blo ts or fluorescence in situ hybridization (FISH). Analysis of BssHII-di gested genomic DNA using these probes was consistent with association of all seven genes with a 905-kb fragment, suggesting physical cluster ing at a single site. The cluster was assigned to chromosome 20 by scr eening a somatic cell hybrid panel with an STS for CST2. This assignme nt was confirmed for each gene by FISH using repeat-free genespecific genomic probes ranging in size from 2.3 to 0.8 kb. All the loci mapped to 20p11.2. (C) 1994 Academic Press, Inc