HUMAN TYPE-I CYTOKERATIN GENES ARE A COMPACT CLUSTER

A YAC clone (211F11) containing approximately 0.5 Mb of human DNA was isolated from a human genomic library by PCR-based screening with cyto keratin (KRT) 13-specific primers. The YAC clone was mapped by FISH to the long arm of chromosome 17 (17q12-->q21), a region to which severa l other type I KRT genes had been mapped previously. We now show by So uthern blot hybridization and PFGE analyses that KRT13, 14, 15, and 16 are all contained within YAC clone 211F11. Long-range restriction map ping analysis of clone 211F11 and of two smaller YAC clones that were also isolated with KRT13-specific primers, suggests that KRT13, 14, 15 , 16 and their linked type I genes KRT17 and 19, are contained in less than 150 kb of genomic DNA. According to our reconstruction it then a ppears that at least six type I KRT genes are arranged in a highly com pact cluster. The three YACs reported in this study represent a new to ol to dissect the molecular structure of the locus of the human type I KRT genes.