CA125 gene and its use for diagnostic and therapeutic interventions

The CA125 gene has been cloned and multiple repeat sequences as well as the carboxy terminus have been identified. The CA125 molecule comprises three major domains: an extracellular amino terminal domain (Domain 1); a large multiple repeat domain (Domain 2); and a carboxy terminal domain (Domain 3) which includes a transmembrane anchor with a short cytoplasmic domain. An amino terminal extension is present. The molecular structure is dominated by a repeat domain comprising 156 amino acid repeat units. More than 60 repeat units have been identified, sequenced, and contiguously placed in the CA125 domain structure. The repeat units encompass an interactive disulfide bridged C-enclosure and the site of OC125 and M11 binding. The repeat sequences demonstrated 70-85% homology to each other. Expression of the repeats was demonstrated in E. coli . The CA125 molecule is anchored at its carboxy terminal through a transmembrane domain and a short cytoplasmic tail.