CHROMOSOMAL MAPPING OF THE HUMAN GENES CKS1 TO 8Q21 AND CKS2 TO 9Q22

The human cdk2/cyclin A kinase complex is a key regulator of the event s of S phase. This complex contains several proteins involved in regul ating its catalytic activity, including one or more of the CKS protein s, which have recently been shown to inhibit the activation of the cdk 2 kinase, To investigate whether the CKS genes may be altered in human neoplasia, we mapped the chromosome locations of CKS1 and CKS2 by flu orescence in situ hybridization (FISH). CKS1 was localized to 8q21, a locus that is seldom grossly altered in cancer. The localization of CK S2 to 9q22 places it very near to a putative tumour suppressor Locus s uggested to be responsible for susceptibility to the Basal Cell Nevus Syndrome (BCNS or Gorlin's syndrome) familial cancer disorder. Six fib roblast cell lines isolated from patients with BCNS were demonstrated by FISH to have both copies of CKS2 present. Partial sequencing of a g enomic clone of CKS2 revealed that the open reading frame lies over th ree exons. Examination of the six cell lines by SSCP and PCR-based seq uencing of the parts of the three exons coding for the full length pro tein demonstrated no consistent divergence from the reported cDNA sequ ence in any exon. It is unlikely that CKS2 is the BCNS tumour suppress or gene.