Selection of Somatic Cell Hybrids Between HGPRT- and APRT- Cells

The chapter discusses the techniques of selection of somatic cell hybrids between hypoxanthine-guanine phosophoribosyltransferase (HGPRT) and adenine phosphoribosyltransferase (APRT) cells. The analysis of mammalian somatic cell hybrids has provided new and fruitful approaches to the study of gene mapping, genetic complementation and dominance tests, differentiated cell functions, and malignancy. The chapter describes a system utilizing a media called GAMA that can be used for the isolation of hybrids between HGPRT- and APRT mutant cell lines. One hybridization experiment is presented to illustrate the use and effectiveness of GAMA selections. As controls, the parental lines, V79-HG^– and CAK-AP^–, were fused to themselves, and a total of 10⁶ cells was seeded into GAMA. The chapter discusses several precautions concerning the use of GAMA. First the amount of hypoxanthine present in the medium is important. Second, the cell density used in the initial plating of cells into GAMA is somewhat critical. Third, cells should not be transferred directly from GAMA to DMEM however should go through a transitional cultivation in DMEM plus adenine and guanine. The GAMA medium for the selection of hybrids between HGPRT^– and APRT^– cells should permit additional flexibility in the production of mammalian somatic cell hybrids.