The DEK gene encodes a protein with one SAP domain. This protein binds to cruciform and superhelical DNA which then induces positive supercoils into closed circular DNA, and is also involved during mRNA processing in splice site selection. Chromosomal aberrations involving this region, increased expression of this gene, and the presence of antibodies against this protein are all associated with various diseases. Two transcript variants encoding different isoforms have been found for this gene.