- CK2(beta)tes gene encodes a testis-specific isoform of the regulatory subunit of casein kinase 2 in Drosophila melanogaster. Kalmykova, A.I., Shevelyov, Y.Y., Polesskaya, O.O., Dobritsa, A.A., Evstafieva, A.G., Boldyreff, B., Issinger, O.G., Gvozdev, V.A. Eur. J. Biochem. (2002)