Methods for obtaining revertants of transformed cells.

TLDR: This chapter describes the three systems based upon the ability of the transformed cells to grow in conditions where the normal cells cannot, and three different selective assays for reversion are described.

Abstract: Publisher Summary This chapter describes the three systems for the isolation of transformed cells based upon the ability of the transformed cells to grow in conditions where the normal cells cannot. These three assays measure (1) the maximum cell density attained by a line in excess serum, (2) the ability of a cell to establish an isolated colony suspended in agar or Methocel, and (3) the ability of a cell line to grow in limiting or depleted sera. In the case of assay (1), most normal cell lines grow in an oriented fashion and exhibit a density-dependent cessation of cell division. In the case of assay (2), a revertant cell line lacks at least one of the properties of a transformed cell line from which it is descended. A revertant may be selected by a modification of the protocol used to isolate the transformed parent. Three different assays for selecting transformants are in current use; therefore, three different selective assays for reversion are described.