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. The amino terminal domain is dominated by its capacity for O-glycosylation and its resultant richness in serine and threonine residues. An amino terminal extension is presented, which comprises four genomic exons. The molecular structure is dominated by a repeat domain comprising 156 amino acid repeat units, which encompass the epitope binding sites. More than 60 repeat units have been identified, sequenced, and contiguously placed in the CA125 domain structure. More specifically, this invention is directed to a CA125 cDNA sequence which can be introduced into animal or human cells to achieve transcription or expression of the cDNA.
